Sustainable electricity generation fuel mix analysis using an integration of multicriteria decision-making and system dynamic approach

To achieve a national energy access target of 90% urban and 51% rural by 2035, combat climate change, and diversify the energy sector in the country, the Zambian government is planning to integrate other renewable energy resources (RESs) such as wind, solar, biomass, and geothermal into the existing hydro generation–based power system. However, to achieve such targets, it is essential for the government to identify suitable combination of the RESs (electricity generation fuel mix) that can provide the greatest sustainability benefit to the country. In this paper, a multicriteria decision-making framework based on analytic hierarchy process and system dynamics techniques is proposed to evaluate and identify the best electricity generation fuel mix for Zambia. The renewable energy generation technologies considered include wind, solar photovoltaic, biomass, and hydropower. The criteria used are categorized as technical, economic, environmental, social, and political. The proposed approach was applied to rank the electricity generation fuel mix based on nine sustainability aspects: land use, CO₂ emissions, job creation, policy promotion affordability, subsidy cost, air pollution reduction, RES electricity production, RES cumulative capacity, and RES initial capital cost. The results indicate that based on availability of RESs and sustainability aspects, in overall, the best future electricity generation mix option for Zambia is scenario with higher hydropower (40%) penetration, wind (30%), solar (20%), and lower biomass (10%) penetration in the overall electricity generation fuel mix, which is mainly due to environmental issues and availability of primary energy resources. The results further indicate that solar ranks first in most of the scenarios even after the penetration weights of RES are adjusted in the sensitivity analysis. The wind was ranked second in most of the scenarios followed by hydropower and last was biomass. These developed electricity generation fuel mix pathways would enable the country meeting the future electricity generation needs target at minimized environmental and social impacts by 2035. Therefore, this study is essential to assist in policy and decision making including planning at strategic level for sustainable energy diversification.     

Compression of spinal cord caused by spinal deformation in a cat

An 8-month-old cat with bilateral hindlimb paresis was admitted. Radiography revealed a curvature of the thoracic spine and a partial deformation of thoracolumbar vertebrae (dorsal extrusion of the cranial and caudal edges). Compression of the spinal cord (T9-L1 and L6-7) was found by myelography. Medicinal treatment did not yield the desired result. Hemilaminectomy and laminectomy were done to relieve pressure on the spinal cord leading to improved gait. It is, however, not clear whether this syndrome was primarily caused by metabolic or genetic factors.     

Conceptualising work activity for CAL systems design

Abstract  As computing technology has increasingly become relevant to people's everyday lives, emphasis is being placed on ensuring Computer Assisted Learning (CAL) tools support users in ways that are meaningful to them. This requirement has highlighted the need to understand the complex and often dynamic social and cultural organisation of collaborating individuals in context. Here, the aim is to conceptualise the natural flow and evolution of work practices so as to inform the design of these systems. This paper reports on empirical findings of an investigation into the design requirements for a CAL system for supporting knowledge sharing activities in an organisation.     

Promoting good governance through regulatory frameworks in African water utilities.

Most public utilities in Africa are operating at very low efficiency levels. This is mainly a result of poor governance leading to a downward spiral in terms of service to customers. Nearly in every case, studies have shown that the root cause of these problems is not necessarily lack of investment but poor choices with regard to sector policies, institutional and regulatory frameworks. The paper will seek to show the need for effective regulatory framework that promotes Good Governance of public utilities leading to their efficient performance. The paper will draw lessons from the Australian water services regulatory framework and apply it to the African water situation. The Australian regulatory framework has been instrumental in promoting Good Governance in the public utilities hence being run efficiently. It is recognised that the African Water and Sanitation Sector where most public utilities are not operating under a clearly defined regulatory framework can learn a lot from the Australian experience.     

Rural people pay for solar: experiences from the Zambia PV-ESCO project

In the eastern province of Zambia, three companies for solar energy services have been operating for more than two years, with 400 clients paying for the use of solar photovoltaic (PV) installations. Clients do not become owners of the systems. Instead, the company continues to charge a fee for keeping the systems in operation. In this way, the useful lifetime of the solar systems is increased, and clients have local access to skilled service and spare parts. The fees for solar services cover the full operational costs of the companies, including battery replacement and makes them independent of further support from government or donors. Results to date show that clients are happy with their systems, which are of a standard solar home (SHS) size of 50 Wp, with four lights and a socket for radio or other light DC appliance. This is in spite of paying a higher price than what was previously spent on candles and kerosene for lighting. The most important benefit cited among the clients is that children now have the possibility to do their homework in the evening. The second most highly valued feature is entertainment, such as radio and video. Solar systems contribute to increased income earning opportunities especially in the service sector. The poorest rural people cannot afford to pay for a solar system in their house, but benefit from systems in the shops.     

Experimental behaviour of concrete filled thin walled steel tubes with tab stiffeners

This paper presents an experimental investigation into the structural behaviour of concrete filled, thin walled, steel tubular stub column with tab stiffeners. The stiffening was attained by welding together four pieces of lipped angle, whereupon two parts of the lips were notched and folded vertically in order to form the tab stiffeners. The effects of the tab stiffeners on the bond and compressive strengths were investigated experimentally using 18 and 10 specimens respectively. It was observed that the tab stiffener does enhance both the bond strength and the axial load capacity of the concrete filled thin walled steel tubular stub column tested.