ASTU ETD

Adama Science and Technology University Library Electronic Theses & Dissertations (ASTU- ETD) is a new digital institutional repository system that collects, preserve and distribute the scholarly output of the university, mainly postgraduate Electronic Thesis and Dissertation (ETD), articles, proceedings. The system is dedicated to help users to find all the information they might require in order to format and successfully submit their graduate thesis, dissertation and publications electronically. The user friendly web interface enables to maximize & optimize the resource sharing among ASTU different Colleges.

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Recent Submissions

Production and Characterization of Fuel Briquettes Made from Agricultural Residue Blended with Organic Wastes Using a Hydraulic Press Designed and Manufactured Locally
(ASTU, April, 2021) Mr. Hunegnaw Baylie (Principal Investigator)
Alternative energy sources have gained attention in order to substitute the dwindling conventional energy sources. In this context, briquetting technology has been applied to utilize loosen organic feedstocks effectively through solid fuel production. The objective of this study was to produce briquettes from agro-industrial and organic wastes in different combination using simple hydraulic press machine and subsequently to study briquettes physical, chemical and mechanical properties. In this research, coffee husk and bagasse as agro-industrial wastes and sawdust, paper residue and Khat as organic wastes were used for briquette making experiment with a binary mixing weight ratio of 0:100, 25:75, 50:50, 75:25 and 100:0 respectively with three selected binders (10 % w/w) namely starch, molasses and gum Arabic. The effect of feedstock combination, variation of binder types and feedstock preheating were studied following standard procedures on briquettes’ physical, mechanical and energy content at ~7 MPa compaction pressure and particle size of < 1 mm (except mashed paper).From the experiment, bulk density of briquettes was ranged from 474 -1107 kg/m3 at preheating temperature of 140 0C. The effect of binders was analyzed using bagasse feedstock which had relatively low bulk density during preheating method. Thus, its highest bulk density was found to be 462.7 kg/m3 for starch binder. Coffee husk feedstock has been selected to study Mechanical strength of briquettes using selected binders and its maximum values was exhibited by starch binder as 80 % shatter resistance index and 9.5 MPa compressive strength next to preheating method at 140 oC. But, other binders’ effect was not that much deviated in the yield of good quality briquettes in terms of density and mechanical strength. Paper briquette alone had the highest value of 99.51 % and 23.10 MPa shatter resistance index and compressive strength respectively regardless of other binders effect. This indicated that paper itself could be a potential binder of other feedstocks. The moisture content, ash content, volatile matter and Fixed carbon of briquettes were ranged from 4.5-9.3 %, 0.45-11.8%, 70.1-83.5 % and 5.79, 18.5% respectively and the calorific values of briquetted fuels ranged from 15.44-18.34 MJ/kg. The significance of this study was meaning full in the production of briquettes with acceptable physical, mechanical and thermal properties by utilizing agro-industrial waste and discarded organic wastes in different combination.
Designing and Prototyping of Multi-Crop Solar Powered Harvester
(ASTU) Getaw Ayay Haileyesus Kebere
The demands on the grains have been being increased radically in Ethiopia. The existing ways of harvesting grains are not differed from the ancient methods. In order to satisfy the needs our ancestors have been being applied their full money, power and times which leads financial and physical weakness and health problems especially on their backbones. No one was hearing and trying to minimize and eradicate this problem. Hence, a simple to operate and cheap in cost harvester is designed and prototyped which is driven by solar power. The machine harvest grains that have grass physical nature such as wheat, barley, Teff, rice even the grass itself for animal feed. The design and prototype were achieved by following a method of reviewing literatures, collecting data, synthesizing and analyzing the mechanism and structure at a preliminary and detail design stage (using manual and CATIA software), making drawings, manufacturing a prototype and testing. The designed harvester has two solar panel 200 watt each, 1.5 hp DC Motor, divider, cutter system, lugged belt conveyor system, two stage power transmission system and two wheels vehicle system. The harvester is 1614.5 mm width, 1602 mm length, 1862.92 mm height and 93.03 Kg mass. It can harvest 609.6 mm width of grain at a speed of 500 mm/s i.e., it can harvest 0.110 ha/hr. The prototype of the solar grain harvester has one hp DC motor, 2.4 m2 solar panel, three-wheels vehicle and cutter assembly. The test shows that the solar energy supplied into the harvester was capable enough to drive the whole system. Therefore, small-scale solar grain harvester will become preferable means of harvester because it is none pollutant and freely available.
The Role of Structures and Geomorphology On The Occurrenceof Groundwater In The Northern Main Ethiopian Rift System
(ASTU) Hassen Shube (PI)Asfaw Erbello(CoI)
The Northern Main Ethiopian Rift system is known by its active geological and tectonicprocesses. This study used integrated field survey, RS and GIS, geological, structural,geomorphological, hydrogeological and hydrogeochemical methods to analyze the roleof geological structures and geomorphology for the occurrence of groundwater inNorthern Main Ethiopian Rift system. The Hydrogeology of the area is characterized bycomplex bimodal composition of geology and geological structures of NE-SW borderfaults and NNE-SSEW WFB, E-W trending transverse fault system, calderas, siliciccenters and spatter cones along the Rift floor.The highly productive aquifer is observed in the Akaki and Adaa plain with the yield(50-60L/S) and Mojo well field (15-30L/S). This is influenced by YTVL that cross-cut theNMER structure formed both shallow and deep aquifer system and due to local andregional recharge and high rainfall from the plateau sector. The Wonji basin is yieldingup to 10L/S from shallow aquifer system of alluvial deposits recharged from Kokareservoir and Awash River flow. Whereas, in Kereyu, and Wolenchiti basin, the yield isvery low to be 1.5L/S and in Lake Beseka region from 3 to 12L/S due to deep circulatedregional aquifer system from Plateau and adjacent escarpment and low local rechargeand recharge from Fantale and Abadir farm to Beseka lake. In the rift axis, due to theintense structures and deep sub surface circulation thermal springs and steams areemerged in Sodere, Geregedi and Boku thermal spring.The Eastern Plain of Dera and Iteya have a yield between 3 to 5 L/S associated to deepseated fault system that makes groundwater flow along the rift sector to undergo a deepcirculation except in Gonde and Huruta high discharge springs that are associated withlocal aquifer. The hydrogeochemical data shows that Ca-Mg-HCO3 of shallow freshgroundwater to NaHCO3 and high TDS (>2,000 mg/l) and EC (>3,000ms/m) highlydeeply evolved and undergone strong water-rock interaction in the subsurface andintermixing of waters in the Beseka lake region.
Synthesis and Luminescent Characteristics of(Ca4-x-y-zBaySrz)(PO4)2O:xEu2+ Phosphors as a Potential Applicationfor White-Light Emitting Diode
(ASTU) Gemechu Deressa
A novel tunable red- to yellow- emitting phosphor, (Ca4-x-yzBaySrz)(PO4)2O:xEu2+ is reported that displays a broad emission from 500 to800nm, and its emission can be adjusted from red to yellow by changing Ba2+ andSr2+ doping concentration. X-ray powder diffraction analysis confirmed the phaseformation. Excitation and emission spectra, and concentration dependence ofemission intensity of the phosphor were investigated. The results showed that withincreasing Ba2+/Sr2+ concentration, the emission peak wavelength blue-shift from594 to 567 nm, and the color can be tuned from red to yellow. When single- phase(Ca2.95Ba0.5Sr0.5)(PO4)2O:0.05Eu2+ phosphor is pumped by a blue InGaN lightemittingdiode we obtain white light with color rending index between 80.0 and 89.0and color temperatures between 3500 and 5450 K, suggesting that this material iscompetitive as a color conversion material for solid state lighting.
CROPS CLASSIFICATION and YIELD ESTIMATION USING SPATIAL AND SPECTRALFEATURES FROM REMOTE SENSING DATA
(ASTU, 4-Apr-22) TAGEL ABONEHWazih MohammedAddisu Mandfro
Absence of advanced technological availability in the Ethiopia Agricultural sector. The estimationof average yield is done by the general crop estimation survey (GCES) technique which relies onthe experiments designed at the time of harvesting period. In the current scenario, getting organizedinformation about the crop status such as crop health, crop growth, acreages, and their estimatedyields were difficult for many developing countries. In addition, the process of crop monitoringsystem was highly prone to error and results biased farming field survey outcome. In this regard, theprocessing and analyzing field survey data was a time-consuming process. To handle theaforementioned pitfalls, we proposed land use land-cover classification and yield estimationalgorithms using a hyperspectral image data. To conduct the experiment, we have utilizedMaximum likelihood, Random Forest and Support Vector machine learning algorithms. Threedifferent Landsat image data have been acquired from the same area in a different time tounderstand the growth status of crops and their pattern in the specified area. A relevant spectralsignatures has been extracted from the LandSat image data to conduct the experiment. From theexperiment result, MLE, RF and SVM classified the land cover with the accuracy of 93, 98, and 97respectively. From the experimental results, we concluded that the application of remote sensingtechnology in the agricultural sector has a significant contribution to improve production efficiency,managing and controlling crop growth, monitoring land use land cover, real-time data processing,analyzing and real-time decision making.