Mechanical Characterization and Measurement of the Damage of <i>Pericopsis elata</i>(Assamela)

The prediction of the mechanical properties of wood and the evolution of its damage has been essential for its application in many fields such as bridges and houses construction, racks of trucks and so on. In more valorization of biomaterials following the example material wood arouses for a few years a?private interest on behalf of the populations. The experimental characterization?makes it possible to consider the mechanical properties local of Pericopsis elata (Assamela) according to various parameters (the wood turpentine, the orientation of wood fibers, water the content, the type of test …). From the?results, we evaluate the mechanical characteristics of Pericopsis elata (Assamela)?according to the three directions of Orthotropy. Then from the tests of load-discharge we measured the evolution of the damage using the variation of the Young modulus, which enabled us to note the reduction in the modulus of elasticity because of the damage following the three directions. Finally we noted a progressive and irreversible degradation of mechanical properties induced by the development of the microscopic cracks within material.

Investigating the Damaging Effects of the Cyclic Discharge in the Uni-Axial Compression of <i>Raphia vinifera</i>L. Arecacea

The bamboo stem, when mature 5 to 6 years, serves as a building material for modest houses and its marrow as packaging purposes. One of the strains related to the uses of bamboo stem is most often the compression towards the axial direction. The phenomenon of damage is very often observed during such loading. The present study on raffia aims to analyze this phenomenon through cyclical stresses as usual. From the results obtained, it was observed in the stress-strain plane, that the area of the hysteresis loops and the residual strain evolve with two parameters: the number of cycles and the stress peaks. The study of energy dissipation has shown that it evolves according to an exponential law as a function of the number of cycles. The distribution of the energy rate along a stem shows that the samples from the zone close to the base store twice (0.0412 MJ/m3) more energy than the samples taken from the top of the foliage (0.019 MJ/m3).

Consideration of some optimization techniques to design a hybrid energy system for a building in Cameroon

To solve the problem energy deficit encountered in developing countries,Hybrid Renewable Energy System(HRES)appears to be a very good solution.The paper presents the optimal design of a hybrid renewable energy system considering the technical i.e Loss of Power Supply Probability(LPSP),economic i.e Cost of Electricity(COE)and Net Present Cost(NPC)and environmental i.e Total Greenhouse gases emission(TGE)aspects using Particle Swarm Optimization(PSO),hybrid Particle Swarm Optimization-Grey Wolf Optimization(PSOGWO),hybrid Grey-Wolf Optimization-Cuckoo Search(GWOCS)and Sine-Cosine Algorithm(SCA)for a Community multimedia center in MAKENENE,Cameroon;where inhabitants have to spend at times 3 to 4 days of blackout.Seven configurations(Scenarios)of hybrid energy systems including PV,WT,Battery and Diesel generator are analyzed considering an average daily energy load of 50.22 kWh with a peak load of 5.6 kW.Four values of the derating factor i.e 0.6,0.7,0.8 and 0.9 are used in this analysis and the best value is 0.9.Scenario 3 with LPSP,COE,NPC,TGE and RF of 0.003%,0.15913$/kWh,46953.0485$,2.3406 kg/year and 99.8%respectively when using GWOCS is found to be the most appropriate for the Community multimedia center.The optimal Scenario is obtained for a system comprising of 18 kW of P_(pv-rated)corresponding to 69 solar panels,3 days of AD corresponding to a total battery capacity of 241 kWh and 1 of N_(dg).