Power generation and its impact on electricity tariff : a case study of Sierra Leone

Bibliography: p. 92-95.Electricity tariffs are generally high in African countries, but a significant share of it is due to inefficiencies in power generation and supply. This work looked at a case study of the Sierra Leone national utility's power generation and its impact on the tariff system. Sierra Leone is a relatively small country along the west coast of Africa. It is one of the least developed countries in the world, but its electricity tariffs are one of highest in Africa. This is largely due to its inefficient power generation. A significant energy input is wasted and there are high energy output losses in the system. About 10% of the energy input is lost because of poor housekeeping and operating practices. On the average 6% of the power generated is consumed by the plant auxiliaries and the station due to old and inefficient equipment. The technical and non-technical losses of the system are alarmingly high averaging about 38% in recent years. Normally, the level of electricity rates is based on revenue requirement, which depends on the operating cost. The average electricity price in Sierra Leone in 2002 was about US$ 0.18. This high tariff is due to cost associated with the above inefficiencies, which increases the operating costs and the type and age of the generating plants. Besides, on the average there is a net decline on the generation output while operating expenses continue to increase. Using the rate-of-return methodology the tariffs were found to be well below the existing utility tariffs if the fuel is imported from the OECD countries

Dynamic analysis of sandwich beam and frame systems

The dynamic analysis of a general class of sandwich beam and frame systems is presented. The beam element employed in the analysis has three degrees of freedom per node, corresponding to the deflection p, the rotation of the beam [straight phi] and the slope Rp/R x . The stiffness and consistent mass matrices of the sandwich beam and frame systems are derived by using the inhomogeneous solution to the fourth order differential equation as the interpolating function between the degrees of freedom of each node in the element. The consistent mass matrix of the sandwich beam element is developed by means of a special shape function consistent with the displacement functions used in the derivation of the stiffness matrix. Superposing the element matrices of the individual elements, the total stiffness and mass matrices of the entire structure can be constructed by a method known as the direct stiffness method which presents the results in a format ideally suited for computer implementation. Static and dynamic problems are included for demonstration of the consistency of the theory; the results are comparable with results published in the literature and the effects of certain important parameters on the frequency results are evaluated. With the introduction of the uniform axial displacement, the element is applicable to frame analysis

Sustaining Community-Based Responses to the COVID-19 Pandemic: Learning Platforms at Work in Freetown, Sierra Leone

In Freetown, Sierra Leone, despite the progress in the official response to the COVID-19 outbreak, there remain concerns about the limited involvement of local communities and the use of bottom-up participatory approaches in the response. While the official response has been characterised by restrictive public health measures such as partial lockdowns and the declaration of a state of a public health emergency, for the urban poor, the implications have been wide-ranging including the deepening of inequalities, especially among residents in slum-like informal settlements who already suffer from pre-COVID-19 structural challenges and vulnerabilities. This includes challenges linked to health systems fragility, environmental risks and uncertainties around livelihoods in the informal economy, which forces many to live from hand to mouth. Ultimately, these vulnerabilities challenge the acceptance and compliance of the restrictive state-led health measures, which puts them at risk of infections. To address these structural inequalities and foster an inclusive dialogue, a City Learning Platform, comprising the Freetown City Council, local community residents and their groups, and a few non-governmental organisations have been working creatively to respond to the COVID-19 challenges faced by the urban poor. But, while this alternative bottom-up approach has allowed the coordination of response to address community-level priorities more effectively, how well the platform has been able to successfully sustain the interest and commitments of vulnerable groups and to build their capacities, co-create knowledge and explore new opportunities has yet to be understood. This article highlights the strategic value of Community Learning Platforms in sustaining local responses to the pandemic. It also explores how social protection measures are shaped into the local response and help tackle deeply entrenched inequalities in the communities. The article additionally reflects on the challenges and opportunities for using the Community Learning Platforms in the COVID-19 response

The impact of residual infections on Anopheles-transmitted Wuchereria bancrofti after multiple rounds of mass drug administration

Background Many countries have made significant progress in the implementation of World Health Organization recommended preventive chemotherapy strategy, to eliminate lymphatic filariasis (LF). However, pertinent challenges such as the existence of areas of residual infections in disease endemic districts pose potential threats to the achievements made. Thus, this study was undertaken to assess the importance of these areas in implementation units (districts) where microfilaria (MF) positive individuals could not be found during the mid-term assessment after three rounds of mass drug administration. Methods This study was undertaken in Bo and Pujehun, two LF endemic districts of Sierra Leone, with baseline MF prevalence of 2 % and 0 % respectively in sentinel sites for monitoring impact of the national programme. Study communities in the districts were purposefully selected and an assessment of LF infection prevalence was conducted together with entomological investigations undertaken to determine the existence of areas with residual MF that could enable transmission by local vectors. The transmission Assessment Survey (TAS) protocol described by WHO was applied in the two districts to determine infection of LF in 6–7 year old children who were born before MDA against LF started. Results The results indicated the presence of MF infected children in Pujehun district. An. gambiae collected in the district were also positive for W. bancrofti, even though the prevalence of infection was below the threshold associated with active transmission. Conclusions Residual infection was detected after three rounds of MDA in Pujehun – a district of 0 % Mf prevalence at the sentinel site. Nevertheless, our results showed that the transmission was contained in a small area. With the scale up of vector control in Anopheles transmission zones, some areas of residual infection may not pose a serious threat for the resurgence of LF if the prevalence of infections observed during TAS are below the threshold required for active transmission of the parasite. However, robust surveillance strategies capable of detecting residual infections must be implemented, together with entomological assessments to determine if ongoing vector control activities, biting rates and infection rates of the vectors can support the transmission of the disease. Furthermore, in areas where mid-term assessments reveal MF prevalence below 1 % or 2 % antigen level, in Anopheles transmission areas with active and effective malaria vector control efforts, the minimum 5 rounds of MDA may not be required before implementing TAS. Thus, we propose a modification of the WHO recommendation for the timing of sentinel and spot-check site assessments in national programs