Optimal Design of a Standalone Photovoltaic Power Supply System for Air Conditioning Application at Samara University as an Alternative to Diesel Generator Source

The aim of this paper is to optimally design a stand alone photovoltaic power supply system for air conditioning application at Samara University to be used as an alternative to diesel generator supply. Samara University is established in samara town, Afar region and has an average daily radiation of 6.10kwh/m2, sun shine duration of about 10 hours. This  condition invites the use of photovoltaic system as an alternative primary energy source to replace the existing diesel generator supply system. Therefore in order to use this energy source for air conditioning application, the cooling load of the building, 628 tons, is estimated using Newton’s thumb rule. The evaporative air conditioning system which is sometimes called desert cooler is selected to condition the estimated cooling load of the dwelling room. The sizing method (numerical method and HOMER software tools) is complementarily used to design a standalone photovoltaic power supply system. Finally, the metric value of the present worth is US $ 3,302,066 and its simple payback is 6.6 years, and this foreseen that the attractiveness of photovoltaic power system as one of renewable energy to be used as an alternative to diesel generator in the near future

Use of e-book readers for improving agricultural extension service in Ethiopia

Global Affairs CanadaInternal Revie

Determinants and Dimensions of Household Food Insecurity in Dire Dawa Town, Ethiopia

Normal 0 false false false Based on primary data collected from 200 household in 2005, this study scrutinizes determinants and the extent of food insecurity in Dire Dawa town. A binary logit model has identified household size, daily income and proportion of expenditure on food, education of household head, sex of household head, access to credit and marital status of the household as significant determinants of food insecurity in the study area. The FGT index result has revealed that 43% of the sampled households cannot meet the daily recommended caloric requirement with a food insecurity gap of 13%. The findings call for action-based advocacy on family planning to curb population growth, provision of technical training to the unemployed that enhances job creativity and competitiveness on the market, access to credit for the needy with proper targeting criterion and expansion of both formal and informal education. Keywords: Food Security; FGT Index; Logit Model; Dire Daw

Hydrometallurgical removal of uranium and thorium from Ethiopian tantalite ore

This study focused on the leaching of uranium and thorium from a high grade Ethiopian tantalite ore using sulfuric acid. The effects of variables such as acid concentration, temperature and leaching time were studied. In general, the leaching efficiency of uranium increases with increasing temperature from 100 to 300 °C whereas the opposite trend was observed for thorium. The amount of uranium leached increased from 69.1% at contact time of 1 hr to 88.6% when the tantalite ore was leached for 3 hrs. On the other hand, for the experiments conditions considered in this study, the leaching behavior of uranium and thorium did not change significantly with varying sulphuric acid concentration from 70 to 90 wt%. Overall, the highest dissolution of uranium and thorium were achieved at 100 °C, 70 wt% H2SO4 concentration and 1 hr contact time

Factors determining household market participation in small ruminant production in the highlands of Ethiopia

Small ruminants, which account for more than half of the domesticated ruminants in the world, are an important component of the farming systems in most developing countries. Despite their economic and social importance, socioeconomic and marketing research on small ruminants has so far been limited, a fact which also holds strongly true in Ethiopia. This study, based on survey data of 5004 Ethiopian smallholder households, uses analysis of descriptive information and econometric analysis to draw implications to promote market orientation. Econometric results are based on estimation of bivariate, ordinal, and multinomial probit models. We find that herd size, herd structure, access to livestock market, and involvement in the institutional services of extension and credit stand out as the most important factors affecting market participation behaviour of households. Our results imply that an effective package of interventions to promote market-oriented small ruminant production will need to include development of livestock market infrastructure and market institutions, improved access to extension and credit use, efficient animal reproduction and management, and proper animal health care

Decomposition of the Kenticha mangano-tantalite ore by HF/H2SO4 and KOH fusion

In this study, the decomposition behavior of Ta and Nb from the mangano-tantalite ore was investigated using HF/H2SO4 mixture and KOH fusion. The effects of reaction time, decomposition temperature, acid and alkaline concentrations, and particle size on the dissolution process were examined. Higher decomposition rates were achieved at 6:2 mol/dm3 ratio of HF and H2SO4, and with the addition of 10 g KOH in the alkali fusion step. In addition, similar trends in decomposition rates between two agents (HF/H2SO4 and KOH) and comparable dissolution performances were observed. The increase in the decomposition temperature initially increased the decomposition rate of manganotantalite for the two systems considered in this study. However, no significant change in the leaching rate of Ta and Nb was observed beyond 50 °C for the HF/H2SO4 system and above 400 °C when using the KOH fusion process. The elemental and compositional analyses of the leached residues using XRF, XRD, and FT-IR spectroscopy indicated that the acid (mixture of HF and H2SO4) decomposition resulted in slightly better dissolution performance for Ta compared with the alkaline fusion method. Overall, the results indicated that KOH can be a suitable alternative decompositi