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Morphology, Thermal Behavior and Dynamic Rheological Properties of Wood Polypropylene Composites

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Materials Sciences and Applications 2013年第11期4卷 730-738页

作者： diène ndiaye Vincent Verney Haroutioun Askanian Sophie Commereuc Adams Tidjani Département de Physique Université Cheikh Anta Diop Dakar Sénégal Institut de Chimie de Clermont-Ferrand Université Blaise Pascal Clermont-Ferrand France CNRS UMR 6296 ICCF Université Blaise Pascal Aubière France Institut de Chimie de Clermont-Ferrand Université Blaise Pascal Clermont-Ferrand France Ecole Nationale Supérieure de Chimie de Clermont-Ferrand Université Blaise Pascal Clermont-Ferrand France Section Physique Appliquée Université Gaston Berger Saint-Louis Sénégal Institut de Chimie de Clermont-Ferrand Université Blaise Pascal Clermont-Ferrand France Ecole Nationale Supérieure de Chimie de Clermont-Ferrand Université Blaise Pascal Clermont-Ferrand France

Wood polymer composites (WPCs) were made with pine and polypropylene matrix (PP). The composites were produced by melt blending in a Brabender at 180°C. Characterization of the samples, with the aid of scanning electron microscopy supplemented by microscope photography, showed an improved dispersion of wood in the polymeric material in presence of polypropylene grafted with maleic anhydride (MAPP) or nanoclay. The use of the MAPP instead of clay seems to have enhanced the level of crystallinity in the composites for the same levels of wood loading and also accelerates the crystallization. Melt rheological measurements of neat PP and PP-wood composites were carried out at 180°C with an ARES Rheometer scientific mechanical spectrometer in oscillatory frequency. All the composites materials exhibit viscoelastic values greater than those for neat PP. The samples containing MAPP as comptabilizer show the higher newtonian viscosity, however, the addition of a small concentration of nanoparticles like nanoclays does not improve the resulting melt viscoelastic behavior of the composite.

关键词： Morphology Thermal Behavior Dynamic Rheological Properties Wood Polypropylene Composites

Study of the Limit of the Technological Transition in the Field of Methanisation in Senegal (from Laboratory Scale to <i>in-Situ</i>Biodigester)

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Journal of Sustainable Bioenergy Systems 2021年第4期11卷 215-226页

作者： Jean Baptiste Mansaly Djicknoum diouf Bruno Piriou diène ndiaye Amadou Seydou Maïga Laboratory of Electronics Computer science Telecommunications and Renewable Energy Gaston Berger University Saint Louis Senegal Centre de coopération Internationale en Recherche Agronomique pour le Développement Montpellier France

The Anaerobic digestion in Senegal is of particular interest to the scientific community given the availability of substrates and their distribution throughout the country. However, from a technological point of view, the existing installations seem to be obsolete, which does not allow to reproduce the results of the laboratory tests. Thus, the present study aims to take stock of the situation in relation to the studies carried out in laboratories and those concerning the actual monitoring of the bio-digesters in situ. In fact, most experimental bio-digesters operate under optimal implementation conditions with strict control of input and output parameters. However, this is not the case for reactors installed in the field, as these so-called bio-digesters are exposed to real environmental conditions with a periodic variation of the physic-chemical parameters in the reactors throughout the day. This leads to a differential behavior of the micro-organisms, thus affecting their performance. This results in lower yields for those digesters operating under real environmental conditions.

关键词： digestion Anaerobic Substrate Temperature pH Inhibitory Factors

Effects of Prandtl and Jacob Numbers and dimensionless Thermal Conductivity on Velocity Profiles in Media (Porous and Liquid)

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Journal of Modern Physics 2024年第10期15卷 1603-1614页

作者： Momath ndiaye Madialène Sene Goumbo ndiaye Department of Hydraulics Rural Engineering Machinery and Renewable Energy UFR Fundamental and Engineering Sciences University of Sine Saloum El Hadj Ibrahima NIASS Kaolack Senegal

In this present study, we analyzed the effects of Prandtl and Jacob numbers and dimensionless thermal conductivity on the velocity profiles in media (porous and liquid). The transfers in the porous medium and the liquid film are described respectively by the improved Wooding model and the classical boundary layer equations. The mesh of the digital domain is considered uniform in the transverse and longitudinal directions. The advection and diffusion terms are discretized with a back-centered and centered scheme respectively. The coupled systems of algebraic equations thus obtained are solved numerically using an iterative line-by-line relaxation method of the Gauss-Seidel type. The results show that the parameters relating to the thermal problem (the dimensionless thermal conductivity, the Prandtl (Pr) and Jacob (Ja) numbers) have no influence on the dimensionless speed, although the thermal and hydrodynamic problems are coupled. Via the heat balance equation. The results obtained show that the parameters relating to the thermal problem have no influence on the dimensionless speed, although the thermal and hydrodynamic problems are coupled via the heat balance equation. So, at first approximation with the chosen constants, we can solve the hydrodynamic problem independently of the thermal problem.

关键词： Condensation Implicit Finite difference Thin Film Porous Material Model Wooding Vertical Wall

Anaerobic Co-digestion of Fish Processing Waste with Cow Manure and Waste of Market (Rests of Fruits and Vegetables): A Lab Scale Batch Test

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Journal of Sustainable Bioenergy Systems 2021年第1期11卷 45-59页

作者： Ndèye Ndickou Kébé Christiane Rieker Papa Abdoulaye Fall Djicknoum diouf diène ndiaye Thomas Mockenhaupt Patrick Beuel Jamile Bursche Laboratory of Electronics Computer Science Telecommunications and Renewable Energy Gaston Berger University Saint-Louis Senegal CIRE (Cologne Institute for Renewable Energy) Bioenergy University of Apllied Sciences of Cologne TH K&#246 ln Cologne Germany Dakar Senegal

The aim of this work was to use fish processing waste (FW) as main substrate for anaerobic digestion. To enhance the biogas production of FW, co-digestion was done with two other substrates: cow dung (CD) and waste o... 详细信息

div style="text-align:justify;"> The aim of this work was to use fish processing waste (FW) as main substrate for anaerobic digestion. To enhance the biogas production of FW, co-digestion was done with two other substrates: cow dung (CD) and waste of market (MW). Batch test was carried out in an 1 L glass digester in a temperature controlled chamber at 38°C. The following mixtures were carried out: FW with CD respectively at different ratios 100:0% (A), 80:20% (B) and 60:40% (C);FW with MW at the following ratio 80:20% (D);FW with CD and MW respectively at these ratios 80:10:10% (F) and 60:20:20% (G). The biogas produced was measured using a milligas counter® and the volume of gas was recorded. The gas composition was determined using gas chromatography. With a pH stable for raw substrates and mixtures, TS and VS (%TS) contents for FW were respectively 31.01% and 91.55%. Between 3 to 13 days of experimentation, the highest flow rate was observed. The percentage of methane was more important for mixtures B and D, 61% and 59% respectively. pH and VOA/TIC were stable at the end of the batch test for all mixtures, meaning that the organic matter was already well digested. The highest values of Volatile Solid Removal (VSR) were found for mixtures C, D, F and G. Therefore, the promising mixtures for next experimentations in large scale are B and D. div>

关键词： Fish Waste Batch Test Co-digestion Flow Rate Organic Matter

Study of the Activation Process of a 2 m3 Pilot Biodigester on a Microfarm Site

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Journal of Agricultural Chemistry and Environment 2023年第4期12卷 397-413页

作者： Jean-Baptiste Mansaly Djicknoum diouf Bruno Pirou Elhadji Mba Bamdo diakhaby Seynabou Lo Amadou Seidou Maïga diène ndiaye Laboratoire Environnement Ingénierie Télécommunications et Energies Renouvelables Université Gaston Berger de Saint-Louis Saint-Louis Sénégal Centre de coopération Internationale en Recherche Agronomique pour le Développement Montpellier France Laboratoire Régional de Saint Louis et UFR-2S Université Gaston Berger Saint Louis Sénégal

A domestic balloon-type digester with 1200 liters of substrate and a 700-litre gas reserve was installed at the Université Gaston Berger pilot farm, which has 4 cows. After an initial load of 1000 L of water, 90 L of bovine rumen and 145 L of cow dung, the functional parameters of the reaction medium, i.e., temperature, pH, salinity and conductimetry, were regularly monitored at a rate of 3 tests per day until the thirtieth day, corresponding to the flame test and the start of analysis and daily loading of the biodigester. The analysis of the biogas obtained after the flame test showed us the considerable contribution of bovine hindquarters to the CH4 fraction, which reached 72.2% from the start of the production phase. As anaerobic digestion is both a complex and multiparametric process, microbiological analysis revealed the presence of several strains of bacteria in the substrate used. Among the most abundant were Escherichia coli, Klebsiella spp, non-fermentative Gram-negative bacilli and Enterococcus sp. However, the bacterial strain that interests us most in anaerobic digestion is the non-fermentative Gram-negative family. We see the identification and temporal monitoring of these families of bacteria as a major step forward in the control of anaerobic fermentation processes in the Sahelian context and in Senegal in particular.

关键词： Pilot digester Activation Bovine Belly Conductimetry Salinity Microbiology Analysis

Study of the Thermal, Rheological, Morphological and Mechanical Properties of Biocomposites Based on Rod-Of Typha/HDPE Made up of Typha Stem and HDPE

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Advances in Materials Physics and Chemistry 2018年第9期8卷 340-357页

作者： Babacar Niang El Hadj Babacar Ly Abdou Karim diallo Nicola Schiavone Haroutioun Askanian Vincent Verney Ansou Malang Badji Mahmoud Kalid diakite diéne ndiaye Section Physique Appliquée Unité de Formation et de Recherche de Sciences Appliquées et de Technologies Université Gaston Berger Saint Louis Sénégal Institut de Chimie de Clermont-Ferrand Université Blaise Pascal Clermont-Ferrand France CNRS UMR 6296 ICCF Université Blaise Pascal Aubière France

The thermal, rheological and morphological properties of composite biomaterials made with mixture of high density polyethylene and typha rod powder (RD) were evaluated. The dynamic mechanical behavior of the samples was studied with 25%, 35% and 45% typha stem powder concentrations. The viscoelastic properties are mainly related to the nature of the polymer and the typha stem powder. Storage (G') and loss (G') moduli increased significantly, depending on the amount of powder in the molten mixture. After a viscosity increase was noticed in low frequency, it decreased in high frequencies, which demonstrates the pseudo-plasticity effect. Morphological and thermal characterization results have shown the dispersion state of the powder and its ability to modify the kinetics crystallization of biocomposites.

关键词： Biocomposite Thermal Rheological Morphological Mechanical Properties

Matrix Riccati Equations in Optimal Control

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Applied Mathematics 2024年第3期15卷 199-213页

作者： Malick ndiaye School of Computer Sciences and Mathematics Marist College Poughkeepsie USA

In this paper, the matrix Riccati equation is considered. There is no general way for solving the matrix Riccati equation despite the many fields to which it applies. While scalar Riccati equation has been studied thoroughly, matrix Riccati equation of which scalar Riccati equations is a particular case, is much less investigated. This article proposes a change of variable that allows to find explicit solution of the Matrix Riccati equation. We then apply this solution to Optimal Control.

关键词： Optimal Control Matrix Riccati Equation Change of Variable

Origin of Sexy Prime Numbers, Origin of Cousin Prime Numbers, Equations from Supposedly Prime Numbers, Origin of the Mersenne Number, Origin of the Fermat Number

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Advances in Pure Mathematics 2024年第5期14卷 321-332页

作者： Mady ndiaye Middle School Badara Mbaye Kaba Dakar Academy Inspection Ministry of National Education of Senegal Dakar Senegal

We have found through calculations that the differences between the closest supposed prime numbers other than 2 and 3 defined in the articles are: 2;4: and 6. For those whose difference is equal to 6, we showed their origin then we classified them into two categories according to their classes, we showed in which context two prime numbers which differ from 6 are called sexy and in what context they are said real sexy prime. For those whose difference is equal to 4, we showed their origin then we showed that two prime numbers which differ from 4, that is to say two cousin prime numbers, are successive. We made an observation on the supposed prime numbers then we established two pairs of equations from this observation and deduced the origin of the Mersenne number and that of the Fermat number.

关键词： Cousin Prime Numbers Sexy Prime Numbers Real Sexy Prime Numbers Equations from Supposed Prime Numbers Mersenne Number Fermat Number Supposed Prime Numbers Prime Numbers

Preliminary Identification of a Prime Number Other Than 2 and 3, the Origin of Twin Prime Numbers, the Structure of the Chain of Prime Numbers and the Set of Prime Numbers Less Than a Given Integer

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Advances in Pure Mathematics 2024年第1期14卷 30-48页

作者： Mady ndiaye Middle School Badara Mbaye Kaba Dakar Academy Inspection Ministry of National Education of Senegal Dakar Senegal

The application of the Euclidean division theorem for the positive integers allowed us to establish a set which contains all the prime numbers and this set we called it set of supposedly prime numbers and we noted it Esp. We subsequently established from the previous set the set of non-prime numbers (the set of numbers belonging to this set and which are not prime) denoted Enp. We then extracted from the set of supposedly prime numbers the numbers which are not prime and the set of remaining number constitutes the set of prime numbers denoted Ep. We have deduced from the previous set, the set of prime numbers between two natural numbers. We have explained during our demonstrations the origin of the twin prime numbers and the structure of the chain of prime numbers.

关键词： Supposedly Prime Numbers Non-Prime Numbers Prime Numbers Prime Numbers Less Than a Given Integer Prime Numbers between Two Given Integers