Modelling and Optimization of Hydroelectric Power Plants in Cameroon for the Development of the Green Energy Market in Neighboring Countries Using Homer Software

Renewable energy is increasingly in demand for a variety of applications in both urban and rural areas. There are, however, a number of implementation constraints in some countries, even though sunshine, wind and water are abundant and available. As part of this research, we are carrying out a technical and economic study on the availability of renewable energy in Cameroon, with a view to combining several sources of solar, biomass, wind and hydroelectric power to meet energy demand both inside and outside the country, in countries such as Chad, Gabon and Nigeria. In this work, the implementation of the entire system in the HOMER software demonstrates the feasibility and possibility of implementing a multi-source power plant based on renewable energies. Calculation of the levelized cost of energy (LCOE) and the net present cost (NPC) shows that a capacity of 485 GW can meet the energy demand of the countries bordering Cameroon. Furthermore, the calculation of the performance ratio gives a PR = 46.52 and a Capacity factor of CF = 11.64. The system is profitable not only economically but also environmentally, as it reduces greenhouse gas emissions and energy losses.

Waste Recovery and Sustainable Development. A Case Study of Material Development from Used Tires in Africa

This paper outlines a mechanical transformation process for rubber recycling, demonstrating the development of a new material from used tires. With the crumbs obtained using a crusher-compactor, a novel material for the manufacture of O-rings has been developed, with properties close to those found on the market. The process includes an experimental methodology of a sulfur vulcanization system choice and the quantification of ingredients, as well as the experimental determination of cure parameters. Mechanical tests on the samples completed the work by providing the mechanical characteristics of both unaged and aged (thermo-oxidative ageing) novel material. This process has a high potential for sustainable development and industrialization, making it a valuable contribution to the recycling of rubber in African developing countries.

Assessment of the Rural Water Supply Potential by Mechanical Wind Pumping Around the Floodplains of Lake Chad

In the present work,an assessment of the rural water supply potential by mechanical wind pumping around the floodplains of Lake Chad has been considered.Inside the floodplains around Lake Chad,available surface water is largely contaminated and represents health hazards to populations.Access to underground and clean water has increasingly become rare.Moreover,clean water scarcity has led to conflict and territorial pressures,which are contributing factors to poverty in the considered area.Four localities,Baga,Baga-Sola,Makari and Nguigmi,respectively,in Nigeria,Chad,Cameroon and Niger have been selected inside the floodplains around Lake Chad,to evaluate the potential of wind power and prospects of windmills development to provide safe drinking-water supply,livestock watering and small-scale irrigation.Long-term satellite-derived data,obtained through the Prediction of Worldwide renewable Energy Resources have been considered suitable and viable alternative to missing site-specific data from ground stations.Windmill of Multi-blade driven piston pump is the preferred water pumping option for this study because of its higher overall system efficiency.The results of this study indicate that mean wind speeds,at 10 m height above ground level,are 4.64 m/s for Baga,4.76 m/s for Baga-Sola,4.32 m/s for Makari and 4.44 m/s for Nguigmi.In addition,wind speeds for Baga,for instance,are in the range of 2.5–10 m(working range of a wind pump),at 10,15,20 and 25 m height agl,for 79.64,82.80,84.79,and 86.19 per cent of the time.Corresponding values for Baga-Sola,Makari and Nguigmi are in the range of 80.50–87.76 per cent,76.86–85,58 per cent,77.92–86.21 per cent,respectively.For a Windmill with a 2 m-blade,a 25 m-height tower and considering a total dynamic head of 30 m,average monthly discharges for the dry season are 1,330,1,374,1,200 and 1,199 m3,respectively for Baga,Baga-Sola,Makari and Nguigmi.Furthermore,corresponding costs of water are 9.53,9.23,10.56 and 10.57 XAF/m3,for Baga,Baga-Sola,Makari and Nguigmi,in that order.

Tracking the maximum power point of solar panels through direct estimation of optimum voltage with temperature

Electricity production from photovoltaic(PV)panels is maximized when the operating point is located at the maximum power point thanks to dedicated controllers.These controllers are driven to track the maximum power by using various algorithms within distributed or centralized architectures accounting for factors such as partial irradiation and temperature changes.The effect of irradiance on the optimal panel voltage is weak or even negligible,while it is strong and quasi-linear-dependent on temperature.Based on this observation,this article introduces a straightforward method for tracking the maximum power of a PV panel by using an optimizer,focusing solely on its temperature response as an input variable.The proposed approach hinges on linearizing the relationship between panel temperature and operating voltage.This relationship enables the estimation of the maximum power point through temperature measurement alone.Thus,after determination of the linear temperature coefficient of the voltage requiring only the knowledge of two optimal voltages at different temperatures,for example from the datasheet of the panel,the power tracking involves only one temperature sensor placed on the panel alongside a voltage sensor for regulation.The principle,modelling,and validation post-panel ageing of the method are detailed in this paper.Simulation,conducted using real experimental irradiation and temperature data,attests to the effectiveness of the control.Results indicate an average effectiveness of the method of>99.1%in tracking the maximum power,with the panel generating 2.33 kWh out of a possible 2.35 kWh.This performance is comparable to that of tracking devices employing more complex algorithms.The simplicity and efficiency of the method make it a promising option for maximizing the power production at low cost from PV systems in small or residential,on-or off-grid connected applications.

A simulation of doping and trap effects on the spectral response of AlGaN ultraviolet detectors

We study,by means of numerical simulation,the impact of doping and traps on the performance of the＂solar blind＂ultraviolet Schottky detector based on AlGaN.We implemented physical models and AlGaN material properties taken from the literature,or from the interpolation between the binary materials（GaN and AlN） weighted by the mole fractions.We found that doping and traps highly impact the spectral response of the device,and in particular a compromise in the doping concentration must be reached in order to optimize the spectral response of the detector.These results give us a powerful tool to quantitatively understand the impact of elaboration and processing conditions on photodetector characteristics,and thus identify the key issues for the development of the technology.

Chaotic light at mid-infrared wavelength

The onset of nonlinear dynamics and chaos is evidenced in a mid-infrared distributed feedback quantum cascade laser both in the temporal and frequency domains.As opposed to the commonly observed route to chaos in semiconductor lasers,which involves undamping of the laser relaxation oscillations,quantum cascade lasers first exhibit regular self-pulsation at the external cavity frequency before entering into a chaotic low-frequency fluctuation regime.The bifurcation sequence,similar to that already observed in class A gas lasers under optical feedback,results from the fast carrier relaxation dynamics occurring in quantum cascade lasers,as confirmed by numerical simulations.Such chaotic behavior can impact various practical applications including spectroscopy,which requires stable single-mode operation.It also allows the development of novel mid-infrared highpower chaotic light sources,thus enabling secure free-space high bit-rate optical communications based on chaos synchronization.

Green CoNi_(2)S_(4)/porphyrin decorated carbon-based nanocomposites for genetic materials detection

A one-pot synthesis method was conceptualized and implemented to develop green carbon-based nanocomposites working as biosensors.Porphyrin was synthesized to adorn the surface of nanocomposites making them highly sensitive for giving rise to π-π interactions between the genetic materials,proteins and porphyrin rings.The hydrogen bond formed between the proteins(analytes)and the nitrogen in the porphyrin structure as well as the surface hydroxyl groups was equally probable.In this context,different forms of porphyrins were incorporated to explore the interrelationship between the surface morphology and the ability of detection of genetic material and/or proteins by the aid of the synthesized structures.This phenomenon was conceptualized to optimize the interactions between the biomolecules and the substrate by reaching significant biosensor application in the presence of Anti-cas9 protein and sgRNA(concentration changed between 10 and 500 n mol/L).Almost full quenching of fluorescence emission was observed after addition of 300 n mol/L of Anti-cas9 protein and 250 n mol/L of sgRNA.Surprisingly,CoNi_(2)S_(4)provided 12%-29%cytotoxicity in both HEK-293 and PC12 cell lines.