Performance of Unidirectional Biocomposite Developed with Piptadeniastrum Africanum Tannin Resin and Urena Lobata Fibers as Reinforcement

The Piptadeniastrum Africanum bark tannin extract was characterized using MALDI TOF,ATR-FT MIR.It was used in the development of a resin with Vachellia nilotica extract as a biohardener.This tannin is consisting of Catechin,Quercetin,Chalcone,Gallocatechin,Epigallocatechin gallate,Epicatechin gallate.The gel time of the resin at natural pH(pH=5.4)is 660 s and its MOE obtained by thermomechanical analysis is 3909 MPa.The tenacity of Urena lobata fibers were tested,woven into unidirectional mats(UD),and used as reinforcement in the development of biocomposite.The fibers tenacity at 20,30 and 50 mm lengths are respectively 65.41,41.04 and 33.86 cN·Tex^(−1).The UD biocomposite obtained had very interesting mechanical properties.Its density,tensile MOE,ultimate strength,bending MOE and MOR are respectively 926 kg·m^(−3),6 GPa,55 MPa,9.3 GPa and 68.3 MPa.This biocomposite can be used in a building exterior structure.

Physico-Chemical and Mineralogical Characterization of Two Clay Materials of the Far North Region of Cameroon(Makabaye,Maroua)

To contribute to the valorization of local materials, the physico-chemical and mineralogical characterization of two clay materials MJ and MN collected in the Mayo Tsanaga river which crosses the Makabaye district of Maroua (Cameroon) was carried out. For this purpose, various methods of characterization have been used, namely granulometric analysis, Atterberg limits, X-ray fluorescence spectrometry and X-ray diffraction. It is apparent from the granulometry that the clay materials studied titrate 33.77% of clays for MJ against 44.13% for MN. The plasticity indices Ip with values IpMJ = 19.27% and IpMN = 23.4% place the materials in the plastic domain and offer them the possibility to being shaped into objects. The chemical composition of the MJ and MN materials reveals that the silicon oxide SiO2, the aluminumoxide Al2O3 and iron oxide Fe2O3 are their main constituents. The X-ray diffraction of the MJ and MN materials shows that they consist mainly of quartz with associated kaolinite, illite, montmorillonite, perlialite, dickite, nacrite, amesite, albite, brookite and anorthite. In addition to these, 2/1 minerals such as muscovite, nontronite, glauconite, and phlogopite are also identified in the MJ material. The peaks of sanidine, microcline and gismondine are also found in the MN material. The materials being rich in clay minerals 2/1 can be valorized in the adsorption and the absorption of the oils and greases and in the waterproofing of the grounds. The presence of quartz, kaolinite and illite is undoubtedly favorable for the manufacture of ceramic products in terracotta. These products will be obtained at a relatively lower temperature due to illite, feldspars and iron minerals that provide vitrification during firing by forming eutectics. The aluminosilicate amorphous phases contained in the studied materials can be exploited to produce geopolymer cements and concretes.

Desorption Behavior and Thermogravimetric Analysis of Bio-Hardeners

In this work,the thermal degradation and drying of bio-hardeners are investigated.Four bio-hardeners based on exudates of Senegalia senegal,Vachellia nilotica,Vachellia seyal,and Acacia siebteriana were analyzed by FTIR and thermogravimetric analysis,and a desorption study was also conducted.The analysis by infrared spectroscopy indicates the existence of oligomers of different types all giving 5-hydroxy-2-hydroxymethylfuran and 2,5-dihydroxymethylfuran which are then the real hardening molecules.The pyrolysis of these extracts reveals three main regions of mass loss,a first region is located between 25℃and 110℃reflecting the loss of water from the adhesive and the formation of some traces of volatile organic compounds such as CO_(2)and CO,a second zone characterized by the release of CO,CO_(2)and CH4 gases with peaks between 110°and 798.8℃.At the end of the analysis,about 22%of the initial mass remains undecomposed,this mass corresponds to the rigid segments of the bio-hardener which are not completely decomposed.

Simulation of a DI Diesel Engine Performance Fuelled on Biodiesel Using a Semi-Empirical 0D Model

Diesel engines have proven over the years important in terms of efficiency and fuel consumption to power generation ratio. Many research works show the potential of biodiesel as a substitute for conventional gasoil. Mainly, previous and recent researches have focused on experimental investigation of diesel engine performance fuelled by biodiesel. Researches on the mathematical description of diesel engine process running on biodiesel are scarce, and mostly about chemical and thermodynamic description of the combustion process of biodiesel rather than performance studies. This work describes a numerical investigation on the performance analysis of a diesel engine fuelled by palm oil biodiesel. The numerical investigation was made using a semi empirical 0D model based on Wiebe’s and Watson’s model which was implemented via the open access numerical calculation software Scilab. The model was validated first by comparing with experimental pressure and performance data of a one cylinder engine at rated speed and secondly by comparing with a six cylinders engine performance data at various crankshaft rotational speeds. Simulations were then made to analyze the engine performance when running on biodiesel. The calculations were made at constant combustion duration and constant coefficient of excess air. Results showed that the model matches the overall experimental data, such as the power output and peak cylinder pressure. The ignition delay was somehow underestimated by the model for the first experiment, which caused a slight gap on in cylinder pressure curve, whereas it predicted the average ignition delay fairly well for the second set of validation. The simulations of engine performance when running on biodiesel confirmed results obtained in previous experimental researches on biodiesel. The model will be further investigated for engine control when shifting to biodiesel fuel.