Design of a pyrolyser model for the conversion of thermoplastics into fuels.

This study focuses on alternatives to the sustainable management of plastic wastes through the development of a pyrolyser model, adapted to the recycling of plastics into fuel. It is a batch reactor, fixed bed, designed and built for the extraction of pyrolysis oil that can be recycled into petrol or diesel. The pyrolyser consists of a reactor with a volume of 0.0424 m3 and a copper spiral condenser with 2.31 m length. The plastics used for this study were Low Density PolyEthylene (LDPE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET). They were collected from surrounding companies, washed, sampled, cut and sieved. Two different sizes of pyrolysis material: 1-3 cm (G1) and 3-7 cm (G2) were obtained and tested. The pyrolysis reactor and the plastics entering at an ambient temperature of 25 °C were heated. Plastics were then melted at 110 °C and vaporised at 450 °C. The hot vapour produced circulated through a copper coil and condensed. The resulting liquid was called pyrolysis oil. The results of this study show that the pyrolysis of LDPE, PP and PS yields two liquids: the heavy and majority fraction which arelike the conventional diesel and the light fraction which is like gasoline. Yields of 6-12.4% for the light fraction and 43.2-63.8% corresponding to the heavy fraction are observed. PE has the highest yield, 63.8% for the heavy fraction and 12.4% for the light fraction. The study further underscores that the size of the pyrolysis material influences the yields, i.e. an increase of 12.5, 9.1 and 7 % for LDPE, PS and PP respectively when the size of the pyrolysis material is increased from G2 to G1. In contrast, the results of PET have shown a liquid that solidifies 46 s later. It was also noticed that 2061.34 kJ of energy was required to pyrolyse 1 kg of plastic and produce 0.762 l of fuel. The simple physico-chemical characterisation of the majority fraction shows a great similarity with diesel fuel, as the distillation went beyond 200 °C. Therefore, we can say that the diesel fraction is similar to diesel fuel. We equally observed a high cetane number (52.1-55.1) and a high calorific value (42.9-55.5 MJ/kg). Consequently, there are some points of non-conformity with the European 590 standard and Cameroonian specifications for diesel fuel. These include a low density (767.8-815.1 kg/m3) and a low viscosity at 40 °C (1.108-1.346 mm2/S). A thorough physico-chemical analysis will complete this study before any recommendation for appropriate use.

A robust image encryption scheme based on compressed sensing and novel 7D oscillato with complex dynamics.

The present work studies a novel efficient compressed based cryptosystem which combines a dynamical parameter coming from high dimensional system, a dynamics S-box and a 2D compress sensing (2D-CS). Firstly, a secret key depending on input image is gotten via the SHA-256 function. That input image, decomposed into four sub-images uses chaotic sequences of the novel 7D multistable system to perform 2D compress sensing. Afterward, the previous compressed image is substituted by the key-dependent Mordell elliptic curve based dynamic S-box. At the end, the diffusion of the substituted image is proceed by chaotic sequences coming from the novel 7D multistable system. The compressed based cryptosystem presented here is considerably dependent on the original image. Moreover, the 7D chaotic system exhibits phenomenon of transient chaos. Equally, we have found plan equilibria hidden attractors which is a good chaos based property in cryptography. Let's recall that up to date, phenomenon of transient chaos and plan equilibria hidden attractors are rarely reported in Josephson junction systems. This denothing the novelty of this article. Through well-known metrics, the results found are evaluated and validated as well as their robustness over brute force attacks. The obtained results are termed as good in accordances with the existing ones over the literature.

Contribution of the mix renewable energy potentials in delivering parts of the electric energy needs in the west region of Cameroon.

The constant supply of energy remains a great challenge in many developing countries and Cameroon is no exception. It is necessary to explore other renewable energy sources that have environmental and energy potential. However, there is limited and sparse literature on the potential of renewable energy sources in Cameroon and its western part in particular. This limits investment and policy design that can lead to the exploitation of renewable energy sources. There is thus a need for more research on renewable energy development to better inform energy policies. This paper investigates the potential and extent to which available renewable energy sources can contribute to the electric power sector in the western part of Cameroon is on estimating the potential of hydroelectric, solar and biomass energy resources. A cross-sectional method, observations and literature review were used to determine the water flow and electrical energy potential of different biomass. The results show that the electrical potential of hydroelectricity is 11.68 GWh/year, for solar represents 44.12 GWh/year, and the energy of biomass 8586.42 GWh/year, 135.53 GWh/year and 13.05 GWh/year for agricultural, animal and forestry residues; they have a rate of access to electricity of 6.64%, 25.08%, 4881.46%, 77.05%, and 7.42% respectively. This potential can satisfy needs of 18 526 464 households. According to results obtained and in order to provide a sustainable solution by improving access to electricity, living standards and socio-economic conditions of populations; two hybrid cogeneration thermal-solar power plants can be installed at the limits of the decentralized areas of Bamboutos-Mifi-Menoua and Noun-Koung Khi, which are nearby areas with high population density. Hydroelectric plants can be installed to electrify villages that are far from the national network.