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Interspecific density-dependent model of predator-prey relationship in the chemostat

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International Journal of Biomathematics 2021年第1期14卷 51-72页

作者： Tahani Mtar radhouane Fekih-Salem Tewfik Sari University of Tunis El Manar National Engineering School of TunisLAMSIN 1002TunisTunisia University of Monastir Higher Institute of Computer Science of Mahdia5111 MahdiaTunisia ITAP Univ MontpellierINRAEInstitut AgroMontpellierFrance

The objective of this study is to analyze a model of competition for one resource in the chemostat with general interspecific density-dependent growth rates,taking into account the predator–prey *** relationship is characterized by the fact that the prey species promotes the growth of the predator species which in turn inhibits the growth of the first *** model is a three-dimensional system of ordinary differential *** the same dilution rates,the model can be reduced to a planar system where the two models have the same local and even global *** existence and stability conditions of all steady states of the reduced model in the plane are determined according to the operating *** the nullcline method,we present a geometric characterization of the existence and stability of all equilibria showing the multiplicity of coexistence steady *** bifurcation diagrams illustrate that the steady states can appear or disappear only through saddle-node or transcritical ***,the operating diagrams describe the asymptotic behavior of this system by varying the control parameters and show the effect of the inhibition of predation on the emergence of the bistability region and the reduction until the disappearance of the coexistence region by increasing this inhibition parameter.

关键词： Bifurcation chemostat coexistence predator-prey relationship operating diagram

Effects of Cadmium on Polar Lipid Composition and Unsaturation in Maize(Zea mays) in Hydroponic Culture

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Journal of Integrative Plant Biology 2007年第12期49卷 1693-1702页

作者： radhouane Chaffai Tinni Nouhou Seybou Brahim Marzouk Ezzedine EI Ferjani Laboratoire de Bio-Physiologie Cellulaires Vegetales Faculte des Sciences de Bizerte 7021 Zarzouna-BizerteTunisie Laboratoire ERTAC Physiologie et Genetique Vegetales 63177 AubiereClermont FerrandFrance Laboratoire d'Adaptation et d'Amelioration des Plantes Institut National de la Recherche Scientifique et Technique(INRST)BP 95-2050 Hammam-LifTunisie

This study aimed to evaluate the effect of Cd exposure （100 μmol/L） on polar lipid composition, and to examine the level of fatty acid unsaturation in maize （Zea mays L.）. In roots, the level of 16：0 and monounsaturated fatty acids （16：1 ＋ 18：1） decreased in phosphatidylcholine （PC） and phosphatidylethanolamine （PE）. In contrast, the proportion of unsaturated 18-C fatty acid species showed an opposite response to Cd. The content, on the other hand, of PC, PE, digalactosyldiacylglycerol （DGDG）, and steryl lipids increased in roots （2.9-, 1.6-, 5.3-, and 1.7-fold increase, respectively）. These results suggest that a more unsaturated fatty acid composition than found in control plants with a concomitant increase in polar lipids may favor seedling growth during Cd exposure. However, the observed increase in the steryl lipid （SL）： phospholipid （PL） ratio （twofold）, the decrease in monogalactosyldiacylglycerol （MGDG）： DGDG ratio, as well as the induction of lipid peroxidation in roots may represent symptoms of membrane injury. In shoots, the unsaturation level was markedly decreased in PC and phosphatidylglycerol （PG） after Cd exposure, but showed a significant increase in sulfoquinovosyldiacylglycerol （SQDG）, MGDG and DGDG. The content of PG and MGDG was decreased by about 65%, while PC accumulated to higher levels （4.4-fold increase）. Taken together, these changes in the polar lipid unsaturation and composition are likely to be due to alterations in the glycerolipid pathway. These results also support the idea that the increase in overall unsaturation plays some role in enabling the plant to withstand the metal exposure.

关键词： cadmium fatty acids heavy metal stress lipid peroxidation polar lipids unsaturation level Zea mays.

High Thermoelectric Figure of Merit of Ag8SnS6 Component Prepared by Electrodeposition Technique

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Chinese Physics Letters 2015年第12期32卷 126-130页

作者： TAHER Ghrib AMAL Lafy Al-Otaibi MUNIRAH Abdullah Almessiere IBTISSEM Ben Assaker radhouane Chtourou Laboratory of Physical Alloys Science Faculty of Dammam University of Dammam Saudi Arabia Laboratoire Photovoltaique Centre de Recherches et des Technologies de l'Energie Technopole bozj cedria Bp 95 hammam lif 2050 Tunisie

A new thermoelectric material Ag8SnS6, with ultra-low thermal conductivity in thin film shape, is prepared on indium tin oxide coated g/ass （ITO） substrates using a chemical process via the electrodeposition technique. The structural, thermal and electrical properties are studied and presented in detail, which demonstrate that the material is of semiconductor type, orthorhombic structure, with a band gap in the order of 1.56eV and a free carrier concentration of 1.46 × 10^17 cm-3. The thermal conductivity, thermal diffusivity, thermal conduction mode, Seebeck coefficient and electrical conductivity are determined using the photo-thermal deflection technique combined with the Boltzmann transport theory and Cahill＇s model, showing that the AgsSnS6 material has a low thermal conductivity of 3.8 Wm - 1K- 1, high electrical conductivity of 2.4 × 10^5 Sm- 1, Seebeck coefficient of -180μVK-1 and a power factor of 6.9mWK-2m-1, implying that it is more efficient than those obtained in recently experimental investigations for thermoelectric devices.

关键词： Figure High Thermoelectric Figure of Merit of Ag8SnS6 Component Prepared by Electrodeposition Technique Ag SnS

Effect of Substrate Nature on the Structural, Optical and Electrical Properties of In2S3 Thin Films

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Journal of Materials Science and Chemical Engineering 2022年第5期10卷 1-15页

作者： Fethi Aousgi Youssef Trabelsi Aoussaj Sbai Billel Khalfallah radhouane Chtourou Laboratory of Nanomaterials and Renewable Energy Systems LaNSER Research and Technology Center of Energy Borj-Cedria Science and Technology Park Hammam-Lif Tunisia Physics Department College of Arts and Sciences in Muhail Asir King Khalid University Abha Saudi Arabia Laboratory of Photovoltaic and Semiconductor Materials University of Tunis El Manar ENIT Tunis Tunisia

In this study, In2S3 thin films have been deposited on ITO and fluorine-tinoxide FTO coated glass substrates by single source vacuum thermal evaporation annealed in vacuum a 300°C - 400°C for 1 h. The samples structure was characterized by X-ray diffraction, revealing the quadratic structure of In2S3 and the crystallinity depends on the temperature of annealing and nature of substrate. The various structural parameters, such as, crystalline size, dislocation density, strain and texture coefficient were calculated. The optical properties show that the refractive index dispersion data obeyed the single oscillator of the Wemple-DiDomenico model. By using this model, the dispersion parameters and the high-frequency dielectric constant were determined. The Hall Effect has been studied at room temperature. The Hall voltages, the Hall coefficient (RH) and mobility (μH) have been measured at different magnetic and electric fields. The films show n-type behavior irrespective of temperature and composition.

关键词： In2S3 Vacuum Evaporation Thin Films X-Ray Diffraction UV-Vis Spectrophotometer Photovoltaic

Thermal Effects on Bond Properties of GFRP Rebars Embedded in Concrete

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Journal of Civil Engineering and Architecture 2010年第3期4卷 1-5页

作者： radhouane Masmoudi Abdelmonem Masmoudi Atef Daoud Mongi Ben Ouezdou Department of Civil Engineering Faculty of Engineering University of Sherbrooke Qc JI K 2R1 Canada Civil Engineering Laboratory National Engineering School of Tunis Tunisia Department of Civil and Environmental Engineering Engineering and Architecture College University of Nizwa 616 Birkat AI Mouz Nizwa Sultanate of Oman

This paper presents the results of an experimental study on the thermal effects on glass fibre reinforced polymer （GFRP） bars embedded in concrete. The pullout test specimens were subjected to temperatures of 40℃, 60℃ and 80℃ during a continuous four months-period of time. The results were compared to the reference specimens （room temperature）. It was found that up to 60℃, the loss in bond strength due to the temperature is not significant, whereas for the 80℃-temperature a reduction of 14% in the bond strength is observed. Also, the bond-slip relationship was modelled using the CMR-model and new coefficients are proposed for the bond-slip behaviour of GFRP bars.

关键词： Ageing bond behaviour concrete glass fibre reinforced polymer (GFRP) pullout tests.

钢和玻璃纤维加固的混凝土纤维复合钢管梁的抗弯强度和性能

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钢结构(中英文) 2010年第12期 89-89页

作者： Hamdy M.Mohamed radhouane Masmoudi

从理论和试验的角度,分析玻璃纤维加固的纤维复合(FRP)钢管混凝土梁(RCFFT)的抗弯强度和性能。共进行10根梁的四等分点加载试验。细丝状环绕的玻璃FRP钢管被用于试验梁的结构模板。其中,6根梁采用玻璃FRP筋加固,而另4根采用一般钢筋加... 详细信息

从理论和试验的角度,分析玻璃纤维加固的纤维复合(FRP)钢管混凝土梁(RCFFT)的抗弯强度和性能。共进行10根梁的四等分点加载试验。细丝状环绕的玻璃FRP钢管被用于试验梁的结构模板。其中,6根梁采用玻璃FRP筋加固,而另4根采用一般钢筋加固。试验参数为FRP钢管管壁厚度、混凝土抗压强度、钢管内部加固材料(钢或FRP筋)的类别和横向加固材料(螺旋钢或FRP钢管)的类别。基于实际测量的荷载、变形和应力值,讨论了梁的屈服强度、极限强度、失效模式和延性。结果显示,FRP钢管梁的延性和强度有所提高。提出一种从线弹性分析理论派生的简化方法,可用于预测RCFFT梁在破坏模式下的屈服弯矩和抵抗弯矩。另外,提出开裂弯矩求解的改进方程,用于说明FRP钢管作为约束结构产生的效应。

关键词：混凝土梁挠度延性纤维复合材料约束结构纤维复合钢管