Ethiopian Journals Online (EJOL)
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SCREENING OF ETHIOPIAN FABA BEAN (VICIA FABA L.) ACCESSIONS FOR RESISTANCE AND YIELD PARAMETERS AGAINST FABA BEAN GALL DISEASE (OLPIDIUM VICIAE) UNDER FIELD CONDITIONS
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Experience on impregnation of wood.en poles with water borne salts
No full textThe paper brief ly describes the experience of the Ethiopian Electric Light and Power Authority in treatment of wooden poles used for over-head power transmission.Two types of treatment methods have been tried by the Authority. They are:1. the COBRA treatment method2. the FULL CELL treatment methodThe first treatment method has been discontinued in favour of the FULL CELL treatment for both technical and economical reasons
A computer controlled pulse penerator for an ST Radar System
No full textA computer controlled pulse genarator for an ST radar system is described. It uses a highly flexible software and a hardware with a small IC count, making the system compact and highly programmable. The parameters of the signals of the pulse generator are initially entered from the keyboard. The computer then generates one period of the set of signals in a suitable coded form. This data is then stored in the memory of the pulse generator which enables the latter to run in an autonomous manner once it is started
The Viability of Solar Energy for Domestic Water Heating in Ethiopian Cities
No full textInvestigation of the possible use of solar energy for domestic water heating is conducted for seven representative Ethiopian cities. In this study, the transient performance of the system is computed using a numerical heat transfer model of a flat-plate collector from the input of average annual climatic data and collector parameters. From the annual contribution of solar energy to the heating load and the estimated investment cost, the pay back period of the heating system for each city is calculated. The research result indicates that domestic water heating by solar energy as a viable alternative to electric water heating
Modeling of Blending Processes
No full textThe blending as to essential properties of raw materials tends to growing importance in chemical process industries recently. That is why the modeling of such processes is an urgent need. It can be shown - on the base of the general model for mechanical macroprocesses - that the modeling of blending processes is possible also in the case of stochastic input and output fluctuations. By means of this model, the influence of input fluctuations on the efficiency of separation processes can be precalculated also
Weight Consideration in the Design of Absorber Plates
No full textA preliminary investigation (that has to supported later by economic analysis) on the design of an absorber plate for use in a liquid-cooled flat plate solar collector is considered. The objective of the design is to maximize collector efficiency factor, F', while simultaneously minimizing the plate weight. By varying the plate thickness, tube spacing and tube diameter weight considerations indicate that tube spacing of 100 mm and plate thickness of 0.25 mm give a fairly large F' while the usage of 10 mm tubes give a reasonable low pressure loss and high inside tube heat transfer coefficient
Analysis of Concrete Slabs Subject to Concentrated Loads
No full textA simplified procedure for the calculation of the additional reinforcement which is required under concentrated loads acting on concrete slabs is provided. The introduced method can also be used for the treatment of line loads. Conditions for the application of this procedure are stated and tables for necessary design values have been prepared. Recommendations for the arrangement of the additionally required reinforcement are given. A numerical example shows the application of the procedure