In this study, the mathematical SIR model (Susceptible-Infected-Recovered (cured and deceased)) was applied to the case of Senegal during the first two waves of the COVID-19 pandemic. During this period, from March 1,...In this study, the mathematical SIR model (Susceptible-Infected-Recovered (cured and deceased)) was applied to the case of Senegal during the first two waves of the COVID-19 pandemic. During this period, from March 1, 2020, to March 30, 2021, the transmission and recovery rates as well as the number of reproduction were calculated and analyzed for the impact of the decisions taken by the Senegalese government. In both waves, the variation of the basic reproduction number as a function of time, with values below one towards the end of each study period, confirms the success of the Senegalese government in controlling the epidemic. The results show that the solution of mandatory mask-wearing is the best decision to counter the spread of the disease. Indeed, the mean number of reproduction is 2.11 in the first wave, and the second wave has a lower mean value of 1.23, while the decisions are less restrictive during this latter wave. Also, a short-term prediction model (about 4 months) was validated on the second wave. The validation criteria of this model reveal a good match between the results of the simulated model and the COVID-19 data reported via the Ministry of Health, Solidarity, and Social Action of Senegal.展开更多
The use of low thermal conductivity materials plays an important role in the construction of energy-efficient buildings. Indeed, the improvement of the thermal properties of building walls reduces energy consumption. ...The use of low thermal conductivity materials plays an important role in the construction of energy-efficient buildings. Indeed, the improvement of the thermal properties of building walls reduces energy consumption. This study aims to determine the thermal and energy balances of a building enveloped with Typha australis on the one hand, and a building without Typha on the other hand (a building constructed with conventional materials) using the commercial software Visual TTH. The results of the heat loss calculations show that the Typha building is 62% more efficient than the conventional building. Also, the studies on air-conditioning needs resulted in energy savings of 1577.136 kWh per year for the Typha building, i.e. 1219 kg per year of CO<sub>2</sub> avoided in the air according to the SENELEC emission factor 0.773/MWh in Senegal.展开更多
<span style="font-family:Verdana;">We studied the temperature distribution and fluid velocity in a box-type solar cooker by using the Finite Element Method (FEM) in Ziguinchor southern of Senegal. Inde...<span style="font-family:Verdana;">We studied the temperature distribution and fluid velocity in a box-type solar cooker by using the Finite Element Method (FEM) in Ziguinchor southern of Senegal. Indeed, this is one of the sunniest countries in the world: more than 3000 hours of sunshine per year with an average temperature of around 30<span style="white-space:nowrap;">˚</span>C. This abundant and exploitable solar energy contributes to the development of more efficient, profitable and clean sources of energy. This will help to satisfy the increasing demand of energy. This numerical model was validated by comparing the numerical results with those of the experiment carried out on a single day. The relative error obtained is below 3%. The model results confirmed the performance of this cooker as its cooking temperature is available for more than seven hours. They have shown that the temperature and internal fluid velocity fields are not homogeneous. The results, although preliminary and encouraging, are a first step towards the complete simulation of a solar cooker integrated into a drying column.</span>展开更多
文摘In this study, the mathematical SIR model (Susceptible-Infected-Recovered (cured and deceased)) was applied to the case of Senegal during the first two waves of the COVID-19 pandemic. During this period, from March 1, 2020, to March 30, 2021, the transmission and recovery rates as well as the number of reproduction were calculated and analyzed for the impact of the decisions taken by the Senegalese government. In both waves, the variation of the basic reproduction number as a function of time, with values below one towards the end of each study period, confirms the success of the Senegalese government in controlling the epidemic. The results show that the solution of mandatory mask-wearing is the best decision to counter the spread of the disease. Indeed, the mean number of reproduction is 2.11 in the first wave, and the second wave has a lower mean value of 1.23, while the decisions are less restrictive during this latter wave. Also, a short-term prediction model (about 4 months) was validated on the second wave. The validation criteria of this model reveal a good match between the results of the simulated model and the COVID-19 data reported via the Ministry of Health, Solidarity, and Social Action of Senegal.
文摘The use of low thermal conductivity materials plays an important role in the construction of energy-efficient buildings. Indeed, the improvement of the thermal properties of building walls reduces energy consumption. This study aims to determine the thermal and energy balances of a building enveloped with Typha australis on the one hand, and a building without Typha on the other hand (a building constructed with conventional materials) using the commercial software Visual TTH. The results of the heat loss calculations show that the Typha building is 62% more efficient than the conventional building. Also, the studies on air-conditioning needs resulted in energy savings of 1577.136 kWh per year for the Typha building, i.e. 1219 kg per year of CO<sub>2</sub> avoided in the air according to the SENELEC emission factor 0.773/MWh in Senegal.
文摘<span style="font-family:Verdana;">We studied the temperature distribution and fluid velocity in a box-type solar cooker by using the Finite Element Method (FEM) in Ziguinchor southern of Senegal. Indeed, this is one of the sunniest countries in the world: more than 3000 hours of sunshine per year with an average temperature of around 30<span style="white-space:nowrap;">˚</span>C. This abundant and exploitable solar energy contributes to the development of more efficient, profitable and clean sources of energy. This will help to satisfy the increasing demand of energy. This numerical model was validated by comparing the numerical results with those of the experiment carried out on a single day. The relative error obtained is below 3%. The model results confirmed the performance of this cooker as its cooking temperature is available for more than seven hours. They have shown that the temperature and internal fluid velocity fields are not homogeneous. The results, although preliminary and encouraging, are a first step towards the complete simulation of a solar cooker integrated into a drying column.</span>
