Study of the Impact of Grid Disconnections on the Production of a Photovoltaic Solar Power Plant: Case of Diamniadio Power Plant

Today, renewable energy projects connected to the interconnected network, with powers of the order of tens of megawatts, are more and more numerous in sub-Saharan Africa. And financing these investments requires a reliable amortization schedule. In the context of photovoltaic systems connected to the interconnected electricity grid, the quintessence of damping is the amount of energy injected into the grid. Thus it is fundamental to know the parameters of this network and their variation. This paper presents an evaluation of the impact of power grid disturbances on the performance of a solar PV plant under real conditions. The CICAD photovoltaic solar plant, connected to the Senelec distribution network, with an installed capacity of 2 MWp is the study setting. An energy audit of the plant is carried out. Then the percentage of each loss is determined: voltage drops, module degradation, inverter efficiency. The duration of each disconnection is measured and recorded daily. The corresponding quantity of lost energy is thus calculated from meteorological data (irradiation, temperature, wind speed, illumination) recorded by the measurement unit in one-minute steps. The observation period is three months. The total duration of disconnections related to the instability of the electrical network during the study period is 46.7 hours. The amount of energy lost is estimated at 22.6 MWh. This represents 2.4% of the actual calculated production.

Epidemiological, Clinical and Therapeutic Characteristics of Hypertensive Type 2 Diabetics at the Marc Sankale Center of Dakar

Introduction: High blood pressure (hypertension) and diabetes mellitus are two major risk factors for cardiovascular disease, which is increasing rapidly in Africa and worldwide. Africa has the highest prevalence rate of hypertension in the world, with 46% of adults over the age of 25 with. Hypertension is common in type 2 diabetes and increases cardiovascular risk. The association of these two pathologies has many particularities in the sub-Saharan subject. The work related to this entity in Africa shows a frequency between 30% and 60%. The objective was to describe the epidemiological, clinical and therapeutic characteristics at the Medical Clinic II of the Abass Ndao Hospital Center in Dakar. Patients Methods: This was a cross-sectional, descriptive and analytical study conducted from 01 December 2016 to 31 January 2017. It focused on patients with cardiothyrosis. Epidemiological data, cardiovascular risk factors, and cardiothoracic characteristics were evaluated. Results: 303 cases were recorded with a prevalence of 42%, an average age of 61.63 years, a sex ratio of 0.22. The age group of [60 - 70] years was the most representative at 36.30%. The BMI (Body Mass Index) average was 27.06 kg/m2. Obesity was 25% and 35% were overweight. Dyslipidemia consisting of an increase in LDL cholesterol > 1 g/l in 79%, a hypercholesterolemia in 57%, a decrease in HDL cholesterol in 13.23% and a hypertriglyceridemia in 28%. Patients with three cardiovascular risk factors accounted for 93.72%. The average fasting glucose level was 2.85 g/l. Hyperglycemia was noted in 65%. The glycosylated hemoglobin is greater than 7% in 47%. The duration of diabetes was less than 5 years in 133 patients or 44%. 70% of patients were treated with oral antidiabetic drugs. Insulin was used in 21.1%. Hypertension was mild in 24.1%, moderate in 23.8% and severe in 14.8%. Hypertension treated with monotherapy was 49%, combination therapy was 43%. Converting enzyme inhibitors (CEI) were used in 44%;20% were Calcium inhibitors and 7 were treated by Angiotensin II Receptor Antagonists (ARA). The inhibitor association of the conversion enzyme/calcium inhibitors (CEI/CI) is in 22%. Statins are used in 23%. The degenerative complications concerned four cases of acute edemas of the lower limbs (AELL), four cases of stroke (AVC). 37% had a balance of the blood pressure and among them 19.5% had followed a monotherapy and 33% a combination therapy. Conclusion: The combination of hypertension and diabetes is common in Africa and increases cardiovascular mortality. Training in the management of diabetes and other cardiovascular risk factors is needed.

Science and Technology Backyard model:implications for sustainable agriculture in Africa

Sustainable food production to feed the growing population in Africa remains a major challenge.Africa has 64%of the global arable land but produces less than 10%of its food locally due to its inherently low soil nutrient concentrations.Poor soil fertility and a lack of fertilizer use are the major constraints to increasing crop yields in Africa.On average only about 8.8 kg NPK fertilizer is applied per hectare by African smallholder farmers.There is therefore considerable potential for increasing food production through sustainable intensification of the cropping systems.The low crop yields in Africa are also partly due to limited farmer access to modern agronomic techniques,including improved crop varieties,a lack of financial resources,and the absence of mechanisms for dissemination of information to smallholders.This study analyzed the Science and Technology Backyards(STBs)model and investigated its use for the transformation of agriculture in Africa.Some key lessons for sustainable crop intensification in Africa can be found from analysis of the STB model which is well established in China.These include(1)scientist-farmer engagement to develop adaptive and innovative technology for sustainable crop production,(2)dissemination of technology by empowering smallholders,especially leading farmers,and(3)the development of an open platform for multiple resource involvement rather than relying on a single mechanism.This review evaluates the benefits of the STB model used in China for adoption to increase agricultural productivity in Africa,with a perspective on sustainable crop intensification on the continent.