Recent Articles

In this study, the synthesis and characterization of vinyl ester/glass microballoon syntactic foams with different weight percentages are investigated. Both the tensile and compressive properties of the syntactic foams are characterized. Generally, the results show that the compressive strength and moduli of several syntactic foam compositions are comparable to those of pure vinyl ester as a matrix resin. Due to the lower density of syntactic foams, the specific compressive properties of SCFT-01 (2wt.%) are higher than all other specimens and closer to neat resin. Similar trends are also observed in the tensile properties. The results show that syntactic foams with vinyl ester matrix possess strength behaviour that varies with different content of glass microballoons. This difference is related to the possibility of particle fracture in the stress range where modulus is calculated from the compressive stress–strain curves. In addition, tensile modulus is found to be 70–80% higher than the compressive modulus for all syntactic foam compositions, but both of them are still lower than neat resin. The results also show that the content of glass microballoons in the syntactic foams should be controlled to obtain a good combination of compressive strength and tensile strength. The reasons are discussed in detail.

This study analyzed the fish market chain of Koka reservoir in Ethiopia which is found in Oromia Region, East shoa and Arsi zones. The objectives of the study were to assess the structure, conduct and performance of fish marketing as well as identify factors affecting fish market supply. The study was based on the data obtained from a sample of 104 fishers and 36 traders in the fish market chain. Both descriptive and econometric methods were employed to analyze the data. About 65% Tilapia (Coroso), 21% Catfish (Ambanza) and 14% Carp (Abasamuel) were the type of fish which dominantly appear in the day to day marketing activities of the fishers. The major determinant factors of market supply were estimated by using multiple linear regression models. The fish market performance was also measured using indicators of marketing margins. According to the results, there were three kinds of fish marketing channels i.e fishers to consumers, fishers to retailers then consumers, fishers to fishery cooperatives, wholesalers then consumers. The result showed that transportation and filleting costs were the largest costs of marketing followed by gutting cost. The price of a kilogram of filleted tilapia varied from 18 birr at landing site to 75 birr at Atiklt Tera in Addis Ababa. The Ordinary Least Square results indicated that education level, availability of credit facility and ownership of fishing license significantly affected the amount of fish supplied to market by fishers in the study area. Expanding adult education in fishery community, facilitating access to credit facility and encouraging fishers to be legal is very important for better harvesting and marketing of fish.