This paper presents the optimal mapping of hybrid energy systems, which are based on wind and PV, with the consideration of energy storage and backup diesel generator, for households in six locations in the South South geopolitical (SS) zone of Nigeria: Benin-city, Warri, Yenagoa, Port Harcourt, Uyo and Calabar. The optima hybrid energy systems are able to meet 7.23 kWh/day of a household's electrical energy. The hybrid energy system for each of the locations was optimally chosen based on HOMER software computation and TOPSIS multi-criteria decision-making algorithm that considers technical, economic, environmental, and sociocultural criteria. Wind energy potential was conducted for the six locations using the Weibull distribution function; the wind speed ranges between 3.21-4.19 m/s at 10m anemological height. The wind speeds and the wind characteristics were extrapolated for 30 m and 50 m hub heights. The solar resource potential across the six locations is also presentedranges between 4.21-4.71 kWh/m 2 /day. The best hybrid system for the locations in Benin-city, Yenagoa and Port Harcourt is the Diesel generator-PV-Wind-Battery system; whereas the best hybrid system for the locations in Warri, Uyo and Calabar is the PV-Wind-Battery system. The hybrid systems in Benin-city, Yenagoa and Port Harcourt emit CO 2 ; only 8.47%, 15.02% and 14.09% of the business as usual (the diesel generator). The payback time ranges between 3.7-5.4 years, using the business as usual cost of energy of 0.893 US$/kWh; whereas the cost of energy of the hybrid systems ranges between 0.459-0.562 US$/kWh, which compares well with available literature in the public domain. The design parameters of the optima hybrid energy systems are also presented. The methodology presented here will serve as a design tool for renewable energy professionals.

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Abstract. Performance of a Sifang mini rice combine, originally developed in China, was evaluated under local farmer field conditions in Benin. Results from field evaluation show that the combine worked satisfactorily on less dense rice fields with minimal weeds at grain moisture contents between 19.1% and 20.1% w.b. on soils with moisture content from 23% to 33% d.b. while causing no significant changes to soil physical properties. With harvesting speed ranging from 0.8 to 4.5 km/h, the harvester had a field capacity of 0.10 to 0.39 ha/h and consumed fuel of up to 11 L/ha while having track slip of 6% to 9%. Harvesting using 2- and 1-L gear offered the best efficiency for IR841 and Nerica L20 rice varieties, respectively. As harvesting speed increased, harvesting efficiency decreased and crop throughput increased irrespective of rice variety. The combine produced low mechanical grain damage with total grain loss ranging from 1.43% to 4.43% and 1.85% to 5.6% for the IR841 and Nerica L20 rice varieties, respectively. At an investment cost of US$5000 and hiring at US$10 per h, owning the mini combine harvester becomes profitable after 342 h of machine use; equivalent to approximately 133 ha of paddy field harvested at a harvesting capacity of 0.39 ha/h. Further testing of the combine under a wide range of crop and soil conditions across different agro-ecological zones and economic comparison with manual harvesting is recommended. This would offer smallholder farmers diverse options of rice harvesting mechanization to facilitate future adoption of improved technologies. Keywords: Crop throughput, Field capacity, Field efficiency, Grain loss, Mini rice combine, Sifang.

Harvesting plays a critical role in the cassava production value chain. A review of some existing cassava harvesting options is necessary to facilitate the proper adaption and uptake of improved harvesting methods applicable to farmers from different parts of the globe. In terms of capacity, manual, semi-manual and fully mechanised harvesting options respectively require about 22-51 man-hha-1, 16-45 man-hha-1 and 1-4 man-hha-1. An added advantage with mechanised options is that the field is left ploughed after harvesting with savings on fuel, time and cost. Mechanised harvesters work best on ridged fields with minimal trash or weeds and relatively dry soils (12-16% d.b. moisture content). Earlier attempts at mechanised harvesting have been affected by constraints such as soil characteristics, nature and size of tubers, depth and width of cluster and bond between tubers and the soil, leading to high tuber damage. Though less research attention is given to cassava harvesting mechanisation, that aspect of the global cassava transformation agenda has always been the problem. There is still room for improvement in the provision of appropriate harvesting options for cassava worldwide and a more concerted effort from both the government and private sector is vital.

A 13-month-old girl presented with red finger marks on both shoulders thought initially to be secondary to child abuse. The appearance of the marks was not typical of bruising of the stated age and there were no social concerns or other medical features of child abuse. Direct questioning revealed that the mother had been gardening on a sunny day and had picked the child up prior to the appearance of the marks. The marks are thought to represent a phytophotodermatitis. Many paediatric skin conditions can mimic child abuse. Recognition of this further possibility will prevent avoidable errors of diagnosis.

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This study analyses technical potential and ex ante socioeconomic impacts of biogas production using cassava waste from agroprocessing plants. An analysis was performed for two biodigesters in two cassava processing communities in Ghana. The results showed that the two communities generate an excess of 4,500 tonnes of cassava peels per year. Using approximately 5% of the peels generated and livestock manure as inoculum can generate approximately 75,000 m3 of gas with an estimated 60% methane content from two separate plants of capacities 500 m3 and 300 m3 in the two communities. If used internally as process fuel, the potential gas available could replace over 300 tonnes of firewood per year for cassava processing. The displacement of firewood with gas could have environmental, economic, and social benefits in creating sustainable development. With a 10 percent discount rate, an assumed 20-year biodigester will have a Net Present Value of approximately US$ 148,000, 7-year Payback Period, and an Internal Rate of Return of 18.7%. The project will create 10 full-time unskilled labour positions during the investment year and 4 positions during operation years.

Background: Nigeria's rural coastline communities have long suffered from the consequences of both poor rural electrification and environmental degradation. Therefore, there is an urgent need to provide an optimal sustainable and environment-friendly energy system for the coastline communities in Nigeria, which has the potential of ameliorating the climate change in this country.