François Zougmoré

Rainfall monitoring based on microwave links from cellular telecommunication networks : first results from a West African test bed

Rainfall monitoring based on commercial terrestrial microwave links is tested for the first time in Burkina Faso, in Sahelian West Africa. In collaboration with one national cellular phone operator, Telecel Faso, the attenuation on a 29 km long microwave link operating at 7 GHz was monitored at 1 s time rate for the monsoon season 2012. The time series of attenuation is transformed into rain rates and compared with rain gauge data. The method is successful in quantifying rainfall: 95% of the rainy days are detected. The correlation with the daily rain gauge series is 0.8, and the season bias is 6%. The correlation at the 5 min time step within each event is also high. These results demonstrate the potential interest of exploiting national and regional wireless telecommunication networks for monitoring rainfall in Africa, where operational rain gauge networks are degrading and the hydrometeorological risk increasing.

Composition of C/sub x/H/sub y/O/sub z/N/sub t/ plasmas out of thermal equilibrium using quite different modified forms of Saha and Guldberg-Waage equations

The aim of this work is to discuss the use of quite different modified forms of Saha and Guldberg-Waage equations to determine the composition of C/sub x/H/sub y/O/sub z/N/sub t/ plasmas in a nonequilibrium thermal state. x, y, z, and t are the initial proportions of carbonic, hydrogen, oxygen, and nitrogen atoms. The computation is made under condition of pressure and electron temperature in the range, respectively, 0.1-1 MPa and 5-30 10/sup 3/ K. We show the influence of each form of Saha and Guldberg-Waage equations on the evolution of major species density, such as hydrogen components (H, H/sub 2/), carbon monoxide (CO), and electrons. These species have a significant influence on the plasmas performances such as thermal and electrical conductivity through the equilibrium composition. We also give the influence of internal partition function calculation on species concentration within the plasma and discuss the choice of internal temperatures.

Competitiveness Level of Photovoltaic Solar Systems in Ouagadougou (Burkina Faso): Study Based on the Domestic Electric Meters Calibration

The mean cost price of electricity in Burkina Faso at the end of the last quarter of 2012 was 158 FCFA/kWh for a country where more than 46% of the population lives below the national poverty threshold. To look for solution to that problem, the resort to photovoltaic solar energy is justified for that country. The purpose of this study is to promote the integration of both technical and economical surveys in solar energy preliminary projects in Ouagadougou. To reach that, investigations were carried out in some households and attention was paid from the calibration of the domestic electric meters. Energy demands collected within each household allow us to design a corresponding solar kit through optimization rules. An estimate was edited and financial viability study for each household was also carried out thereafter. In this study, only households using the national electricity network calibration meter on their disadvantage favorably answered to all financial indicators and appear as the only one that could profit from such project. This work is helpful to note that photovoltaic solar energy still stays at a primitive level of competitiveness compared to conventional energy resources for small systems in Ouagadougou.

Calculation of air-water vapor mixtures thermal plasmas transport coefficients

Knowledge of transport coefficients of air-water vapor mixtures thermal plasmas is important to estimate the performances of electrical arc cutting in this gas by a circuit breaker. In this paper, air-water vapor mixtures thermal plasmas dynamical viscosity, thermal and electrical conductivities coefficients are calculated in a temperature range from 5000K to 30000K. The calculations are carried out by supposing local thermodynamic equilibrium at pressure of 1.0 atm, 5.0 atm and 10 atm. The calculation results show the influence of the water vapor initial proportion but also that of the plasmas pressure on these transport coefficients. The plasma of the mixture constituted by 20% of air and 80% of water vapor presents at first sight good characteristics for the electric current cut. It has the highest thermal conductivity and the lowest electrical conductivity among plasmas of studied mixtures.

Influence of Temperature and State Of Charge on Lithium-Ion and Lead Acid Batteries Performance in a Photovoltaic Application

The storage of energy is a very important part of a photovoltaic system. Lithium-ion and lead-acid batteries are generally used for this purpose. This article compares the performance of these two types of batteries in a photovoltaic (PV) system under variation of temperature and state of charge. The PV generator, the lead-acid battery or the lithiumion battery were modelled and then simulated using the Matlab / Simulink simulation environment. By taking into account the influence of temperature and state of charge, the simulation results show that lithium-ion technology is the most suitable for the storage of energy in a photovoltaic system.

Modeling of ballistic and trapping effects on the collection efficiency of holes and electrons separately for a planar mercuric iodide detector (HgI2)

Abstract For the room temperature nuclear detector application, signal created in the detector depends not only to the energy of the incident photon but also to the position of the interaction. This can bring an incomplete charge collection caused by a deep-trapping or a ballistic deficit of charge carrier. Many scientists used to demonstrate their impact on the global efficiency of the charge collection. Here we show this effect, not globally but separately, according to the position where holes and electrons are created. It permits us to see the contribution of each kind of carrier in the signal formation. An analytical model of charge collection is developed firstly to take into account the deep-trapping only. Secondly, this model is improved adding the ballistic deficit effect. The deep-trapping contributes to reduce the efficiency of hole above all on thicker detector. In the other part, ballistic deficit reduce electron efficiency above all near anode in the negatively polarized detector.