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Microwave Transmission Through One-Dimensional Hybrid Quasi-Regular （Fibonacci and Thue-Morse）/ Periodic Structures

Photonic Sensors 2013年第3期3卷 246-255页

作者： Youssef TRABELSI Naim BENALI Yassine BOUAZZI mounir KANZARI LPMS Laboratory of Photovoltaic and Semi-conductor Materials ENIT EL Manar University ENIT-BP 37 Belvedere 1002 Tunis Tunisia

The transmission properties of hybrid quasi-periodic photonic systems （HQPS） made by the combination of one-dimensional periodic photonic crystals （PPCs） and quasi-periodic photonic crystals （QPCs） were theoretically studied. The hybrid quasi-periodic photonic lattice based on the hetero-structures was built from the Fibonacci and Thue-Morse sequences. We addressed the microwave properties of waves through the one-dimensional symmetric Fibonacci, and Thue-Morse system i.e., a quasi-periodic structure was made up of two different dielectric materials （Rogers and air）, in the quarter wavelength condition. It shows that controlling the Fibonacci parameters permits to obtain selective optical filters with the narrow passband and polychromatic stop band filters with varied properties which can be controlled as desired. From the results, we presented the self-similar features of the spectra, and we also presented the fractal process through a return map of the transmission coefficients. We extracted powerfully the band gaps of hybrid quasi-periodic multilayered structures, called ＂pseudo band gaps＂, often containing resonant states, which could be considered as a manifestation of numerous defects distributed along the structure. The results of transmittance spectra showed that the cutoff frequency could be manipulated through the thicknesses of the defects and the type of dielectric layers of the system. Taken together, the above two properties provide favorable conditions for the design of an all-microwave intermediate reflector.

关键词： Photonic crystals aperiodic sequence quasi-periodic photonic band gap Thue-Morse class quasi-periodic Fibonacci class quasi-periodic microwave reflector

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Morphological, Structural, Thermal and Tensile Properties of High Density Polyethylene Composites Reinforced with Treated Argan Nut Shell Particles

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Journal of Bionic Engineering 2015年第1期12卷 129-141页

作者： Hamid Essabir mounir EI Achaby EI Moukhtar Hilali Rachid Bouhfid AbouEIkacem Qaiss Moroccan Foundation for Advanced Science Innovation and Research (MAScIR) Institute of Nanomaterials and Nanotechnology (NANOTECH) Laboratory of Polymer Processing Rabat Morocco National School of Applied Sciences Ibn Zohr University Laboratory Mechanics Processes Energy and Environment Agadir Morocco

High Density Polyethylene （HDPE） composites reinforced with treated bio-filler from Argan-Nut Shell （ANS） at various filler contents are prepared by extrusion and injection molding processes. The microstructures of the composites are charac- terized by Fourier Transform Infrared Spectroscopy （FTIS） and Scanning Electron Microscopy （SEM）; the thermal stability is analyzed by Thermogravimetric Analysis （TGA）, and their mechanical properties are investigated by dynamical mechanical analysis and rheological testing. The morphological and structural results indicate an improvement in adhesion between the ANS fillers and HDPE matrix upon alkali treatment. The mechanical properties of the composites show a significant increase in young＇s modulus with the addition of filler, a gain of 58% is marked compared to neat polymer, Thermal analysis reveals that the incorporation of bio-filler in polymer results in a decrease in decomposition temperatures. This research offers an ecological alternative to upgrade the valorization of abundant and unexploited Moroccan resources. In addition, the possibility of finding uses for ANS in composite manufacturing will help open new markets for what is normally considered waste or for use in low value products.

关键词： argan tree argan nut shell particles polymer composite melt extrusion mechanical properties

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Rangelands of Central Asia:challenges and opportunities

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Journal of Arid Land 2016年第1期8卷 93-108页

作者： Alisher MIRZABAEV Mohamed AHMED Jutta WERNER John PENDER mounir LOUHAICHI Center for Development Research University of Bonn Monitoring African Food and Agricultural Policies Agricultural Development Economics Division Food and Agriculture Organization of the United Nations Diversification and Sustainable Intensification of Production Systems Program International Center for Agricultural Research in the Dry Areas Farm and Rural Household Well-being Branch Economic Research Service United States Department of Agriculture

Rangelands of Central Asia (referring to Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan in this study), the largest contiguous area of grazed land in the world, serve as an important source of livelihood for pastoral and agro-pastoral communities in this region. They also play an important role in absorbing CO2 as a global carbon sink. However, unsustainable management of rangelands has led to their degradation hugely by downgrading their potential agro-ecological, environmental and socio-economical roles. This paper reviewed the rangeland degradation in Central Asia, a topic which so far has received only scant coverage in the international scientific literature. It also provided examples of successful experiences and outlined possible options that land managers can adopt to enhance the sustainable management of these vast degraded rangelands. The experiences and lessons described in this paper may also be relevant for other degraded rangeland areas, especially in the developing countries. The causes of rangeland degradation within the Central Asian region are numerous, complex and inter-related. Therefore, while addressing the factors associated with improper rangeland management may shed some light on the causes of rangeland degradation, the scope of this paper would not be all-encompassing for the major causes of degradation. There is a need to develop and widely apply the viable and locally accepted and adapted packages of technical, institutional and policy options for sustainable rangeland management. Incentivizing the collective action of small-scale pastoralists who group together to facilitate access to remote pastures can reduce the degree of overgrazing within community pastures, such as those near the settlements. We also found that migratory grazing through pooling of resources among small-scale pastoralists can increase household income. After their independence, most Central Asian countries adopted various rangeland tenure

关键词： rangeland degradation flock mobility overgrazing sustainable rangeland management drylands land tenure

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Rethinking Data Center Networks:Machine Learning Enables Network Intelligence

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Journal of Communications and Information Networks 2022年第2期7卷 157-169页

作者： Bo Li Ting Wang Peng Yang Mingsong Chen mounir Hamdi Shanghai Key Laboratory of Trustworthy Computing the Engineering Research Center of Soft-ware/Hardware Co-design Technology and Applicationthe Ministry of EducationEast China Normal UniversityShanghai 200062China College of Science and Engineering Hamad Bin Khalifa UniversityDoha 999043Qatar

To support the needs of ever-growing cloudbased services,the number of servers and network devices in data centers is increasing exponentially,which in turn results in high complexities and difficulties in network *** learning(ML)provides an effective way to deal with these challenges by enabling network *** this end,numerous creative ML-based approaches have been put forward in recent ***,the intelligent optimization of data center networks(DCN)still faces enormous *** the best of our knowledge,there is a lack of systematic and original investigations with in-depth analysis on intelligent *** this end,in this paper,we investigate the application of ML to DCN optimization and provide a general overview and in-depth analysis of the recent works,covering flow prediction,flow classification,and resource ***,we also give unique insights into the technology evolution of the fusion of DCN and ML,together with some challenges and future research opportunities.

关键词： data center network intelligent optimiza-tion machine learning network intelligence

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Thermomechanical Characterization of a Bio-Sourced Material Based on Clay and Alfa Fibers

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Fluid Dynamics & Materials Processing 2022年第6期18卷 1853-1863页

作者： Sara Ibn-Elhaj Yassine Elhamdouni Soumia mounir Abdelhamid Khabbazi EMDD_CERNE2D Mohammed V University in RabatHigher School of Technology SaléSalé11060Morocco National School of Architecture Agadir New Complex Ibn ZohrAgadir80000Morocco

Bio-based materials are of great interest owing to their abundance and the immense potential they display as an ideal alternative to widely used industrial construction materials(that directly and indirectly harm the environment).In this scope,an in-depth experimental study is presented here on clay-based materials aimed to enhance their properties through the addition of other bio-based components such as fibers,in the present case alfa *** thermal conductivity and mechanical properties(compressive and flexural tensile strengths)of the composite clay-alfa material are analyzed with the percentage of alfa fiber in the matrix ranging from 0%to 4%.It is concluded that a percentage of alfa fibers between 1%and 2%is the most effective to get the required optimization of thermal and mechanical behavior of this bio-based material.

关键词： Hot plate method in a steady-state regime clay composite mechanical alfa fiber

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Enhanced photocatalytic activities of silicon nanowires/graphene oxide nanocomposite:Effect of etching parameters

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Journal of Environmental Sciences 2021年第3期33卷 123-134页

作者： mounir Gaidi Kais Daoudi Soumya Columbus Anouar Hajjaji My Ali El Khakani Brahim Bessais Department of Applied Physics and Astronomy University of SharjahSharjah 27272United Arab Emirates Sharjah Centre for Advanced Materials Research Research Institute of Sciences and EngineeringUniversity of SharjahSharjah 27272United Arab Emirates Sharjah Sharjah Research Academy University CitySharjah 60999United Arab Emirates Sharjah Laboratoire de Photovoltaïque Centre de Recherches et des Technologies de l’EnergieTechnopole de Borj-CédriaHammam-Lif 2050Tunisia Institut National de la Recherche Scientifique(INRS) INRS-ÉnergieMatériaux et Télécommunications1650Blvd.Lionel-BouletVarennesQC J3X-1S2Canada

Homogeneous and vertically aligned silicon nanowires(SiNWs)were successfully fabricated using silver assisted chemical etching *** prepared samples were characterized using scanning electron microscopy,transmission electron microscopy and atomic force *** degradation properties of graphene oxide(GO)modified SiNWs have been *** found that the SiNWs morphology depends on etching time and etchant *** SiNWs length could be tuned from 1 to 42μm,respectively when varying the etching time from 5 to 30 *** etchant concentration was found to accelerate the etching process;doubling the concentrations increases the length of the SiNWs by a factor of two for fixed etching *** in bundle morphology were also studied as function of etching *** SiNWs diameter was found to be independent of etching time or etchant composition while the size of the SiNWs bundle increases with increasing etching time and etchant *** addition of GO was found to improve significantly the photocatalytic activity of SiNWs.A strong correlation between etching parameters and photocatalysis efficiency has been observed,mainly for SiNWs prepared at optimum etching time and etchant concentrations of 10 min and 4:1:8.A degradation of92%was obtained which further improved to 96%by addition of hydrogen *** degradation efficiency of 16%and 31%has been observed for bare Si and GO/bare Si samples *** obtained results demonstrate that the developed SiNWs/GO composite exhibits excellent photocatalytic performance and could be used as potential platform for the degradation of organic pollutants.

关键词： Photocatalysis Nanomaterials Methylene Blue Silicon nanowire Graphene oxide Water treatment

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Fluid Flow and Convective Heat Transfer in a Water Chemical Condenser

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Fluid Dynamics & Materials Processing 2020年第2期16卷 199-209页

作者： mounir Kriraa Khalid Souhar Driss Achemlal Youssef Ait Yassine Abdelmajid Farchi IMII Ingénierie Management et Innovation IndustriellFSTHassan 1er UniversitySettatMorocco LMPEQ National School of Applied SciencesSafiCadi Ayyad UniversityMarrakechMorocco LGEMS Laboratory National School of Applied SciencesIbn Zohr UniversityAgadir80000Morocco Engineering Sciences Laboratory Department of MathematicsPhysics and InformaticsPolydisciplinary Faculty of TazaSidi Mohamed Ben Abdellah UniversityFezMorocco Ibn Zohr University Higher School of TechnologyLaâyouneMorocco Ibn Zohr University Faculty of ScienceLaboratory of Thermodynamics and EnergyAgadirMorocco

In this paper,a detailed investigation of water(Pr=7.0)convection in a chemical condenser is carried *** openings are located along one side of the *** Navier-Stokes equations are solved in the frame of a control volume method using the SIMPLEC algorithm to implement adequate coupling of pressure and *** emphasis is given to the influence of the Reynolds number,the tilt of the channel and the Rayleigh number on the convective heat *** are presented and discussed allowing the control parameters to span relatively wide intervals:Rayleigh number(10^(4)≤Ra≤5×10^(5)),channel inclination(0°≤90°)and Reynolds number(10≤Re≤1000).On the basis of these results,a new correlation of the Nusselt number is elaborated.

关键词： Chemical condenser tilted channel convection numerical study heat transfer

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Evaluation of rainwater harvesting and shrub establishment methods for sustainable watershed management in northern Afghanistan

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Journal of Mountain Science 2022年第8期19卷 2346-2359页

作者： LOUHAICHI mounir HASSAN Sawsan GAMOUN Mouldi SAFI Navin ABDALLAH Mohamed A.B. ATES Serkan International Center for Agricultural Research in the Dry Areas(ICARDA) Tunis 1004Tunisia Department of Animal and Rangeland Sciences Oregon State UniversityCorvallisOR 97331USA International Center for Agricultural Research in the Dry Areas(ICARDA) Amman 11185Jordan Consultant-Field Assistant Mazar Sharif 1703Afghanistan

Watershed rangelands in Northern Afghanistan provide various ecosystem services that support the local people's livelihoods,but they are now highly degraded essentially due to the continuous high grazing pressure and recurrent *** of shrub establishment method enhanced by water harvesting techniques to rehabilitate degraded rangelands have not been well *** main goal of this study was to evaluate the impact of direct seeding and transplanting of seedlings in combination with semi-circular bunds on growth,yield,and survival rate of four shrub species(Atriplex halimus,Atriplex nummularia,Atriplex lentiformis,andMaireana brevifolia)under semi-arid conditions of Sayyad village,Khulm *** rate(%),plant height,width,and plant length(cm)and plant cover(%)were measured for each plant over five occasions.A non-destructive reference unit was used to estimate biomass *** results showed that growth attributes and biomass production of shrubs were consistently greater in the transplanting compared to direct *** average,the plant length,width,height,volume,cover,and biomass production of transplanted shrubs were greater than direct-seeded shrubs by 24.3%,8.6%,8.7%,121.5%,13.8% and 34.1%,*** production of transplanted seedlings was the highest for ***(1313.5 g DM/plant)and ***(800 g DM/plant).There was a strong correlation between plant biomass production and plant volume(R^(2)_(Plant volume)=0.88)for the shrub ***,indicating that plant volume is a key variable for assessing biomass production for this ***,the survival rate of *** was 100% in both planting methods,suggesting that based on better survival this halophytic plant has great potential when restoring degraded ***,on the basis of better growth rates,yield,and survival,transplanting *** *** may enhance shrub establishment and contribute to the rehabilitation of slop

关键词： Biomass production Land degradation Rangeland rehabilitation Seed germination Shrub survival Vegetation cover Water harvesting

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Assessment of water body change and sedimentation rate in Moulay Bousselham wetland, Morocco, using geospatial technologies

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International Journal of Sediment Research 2019年第1期34卷 65-72页

作者： mounir Karim Mehdi Maanan Mohamed Maanan Hassan Rhinane Henri Rueff Lahssen Baidder Hassan Ⅱ University of Casablanca Faculty of Sciences An ChockCeosciences Laboratory Universite de Nantes Institut de Geographie University of Basel Department of Environmental Sciences

Coastal lagoons have significant biodiversity and ecologic and socio-economic interest. Several resident and migratory birds live in coastal lagoons as well as fish and other aquatic biota. Over the years, lagoons worldwide have been subject to considerable sediment deposition coming especially from soil erosion due of agricultural activities, and the lagoon’s inflows have resulted in an accelerated sedimentation which can drastically affect the aquatic ecosystem balance. A new, fast, and cost-effective approach was developed, using water surface change as a proxy, to evaluate the sediment deposition rate. In the current research, this methodology was applied in the Moulay Bousselham Lagoon in Morocco, and a combination of Landsat 8 and Landsat 5 imagery acquired at four points in time over 30 years(1985-2015) was used. Following geometric correction and enhancement, the interpretation of the acquired images provided important insight on the current conditions of the water surface change using the Normalized Difference Water Index(NDWI). Several iterations were done to determine a suitable threshold for effective water surface detection. In order to validate the automatically extracted water surface features, many band combinations of Landsat and Sentinel 2 were used as references to run the accuracy assessment. The results show that the Moulay Bousselham Lagoon lost 17.60%(106 ha) of its water surface area, and 530,000 m~3 to 1,060,000 m~3 of its water volume during the last three *** water surface loss into sedimentation returned a rate of 0.58 cm/yr. These results have been confirmed by previous field work using sedimentological approaches. Proper management should be applied to sustain the vitality of this lagoon environment.

关键词： Environmental monitoring Remote sensing GIS Spatial analyst Human/nature interaction Sustainability planning

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Impact of rangeland enclosure and seasonal grazing on protected and unprotected rangelands in Chakwal region, Pakistan

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Journal of Mountain Science 2022年第4期19卷 46-57页

作者： ISLAM Muhammad RAZZAQ Abdul ZUBAIR Muhammad HASSAN Sawsan AHMAD Sarfraz GUL Shamim RISCHKOWSKY Barbara LOUHAICHI mounir International Center for Agricultural Research in Dry Areas(ICARDA) South AsiaIslamabad 44050Pakistan Animal Science Division Pakistan Agricultural Research CouncilIslamabad 44050Pakistan Department of Forestry and Range Management Bahauddin Zakariya UniversityMultan 66000Pakistan International Center for Agricultural Research in Dry Areas(ICARDA) Amman 11185Jordan Natural Resource Division Pakistan Agricultural Research CouncilIslamabad 44050Pakistan Botany Department University of Balochistan Quetta 87300Pakistan Department of Natural Resource Sciences McGill UniversityQuebec H9X3V9Canada International Center for Agricultural Research in Dry Areas(ICARDA) SSAILRI campusAddis Ababa 5689Ethiopia International Center for Agricultural Research in Dry Areas(ICARDA) Tunis 1004Tunisia

Scrub rangelands support livestock grazing and provide ecosystem services to their inhabitants. The present study was conducted in Chakwal, an important tract of the Pothwar Plateau,which sustains herds of small domestic and nomadic ruminants. Urbanization and uncontrolled grazing practices have reduced rangeland productivity and increased soil erosion and resulted in poor land conditions. This study assessed the influence of two years of rangeland protection on aboveground vegetation biomass and the chemical composition of plants and aimed to determine the influence of seasonal grazing on the live-weight gain of small *** the line intercept method, vegetation data from protected and unprotected plots in 2015 and 2016 were collected at two sites, Dhulli and *** cover was assessed from images using VegMeasure. Results showed that protected study sites displayed higher vegetation biomass(834 and 690 kg ha^(-1)) compared to the unprotected study site(477 and 326 kg ha^(-1)) during April and August of both years. In the seasonal grazing trial, the experimental ewes that grazed on protected rangelands showed higher live-weight gain(33–63 g day^(-1)) compared to live weight of ewes(17–21 g day^(-1)) that grazed on unprotected rangelands during the experimental period of 127 days at both sites. The results suggest that the Chakwal rangeland has tremendous potential to improve vegetation productivity but modern livestock management and seasonal grazing practices are needed to improve carrying capacity and livestock productivity.

关键词： Seasonal grazing Climate change Productivity Rangeland Protected area

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