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Über dieses Buch

This book constitutes the refereed post-conference proceedings of the 6th International Conference on Advancement of Science and Technology, ICAST 2018, which took place in Bahir Dar, Ethiopia, in October 2018. The 47 revised full papers were carefully reviewed and selected from 71 submissions. The papers present economic and technologic developments in modern societies in five tracks: agro-processing industries for sustainable development, water resources development for the shared vision in blue Nile basin, IT and computer technology innovation, recent advances in electrical and computer engineering, progresses in product design and system optimization.

Inhaltsverzeichnis

Frontmatter

Application of Lean Tools for Reduction of Manufacturing Lead Time

In the recent years, manufacturing industries are trying to improve customer service by reducing wastes, reducing lead time, improving quality and improving productivity using lean tools. Value Stream Mapping is one of the lean tools for analyzing the current state and designing a future state for the series of events that take a product from its beginning through delivery to the customer. The goal of this study is to apply Value Stream Mapping in production line of Fuel tank semi trailers at XYZ PLC Metal Industry for reducing the manufacturing lead time. In this case study, the existing state of the production line is mapped with the help of Value Stream Mapping process symbols and the biggest improvement areas like excessive work in process and long lead time are identified. Some improvements in current state Value Stream Mapping are suggested and with these improvements future state Value Stream Mapping is developed. Current state and future state of the production line are compared; the results show that 47.45% reduction in lead time, 50.2% reduction in work in process time, 59.2% reduction in total waiting time, 72.72% reduction in number of work in process products, 7% reduction in number of workers and over 89.65% increase in the yearly throughput of products.

Star Abrham, Sisay Geremew

Predicting Runoff, Sediment and Management Scenarios for Reducing Soil Erosion in Data Scarce Regions, Blue Nile Basin

This study presents modeling runoff and sediment with management scenarios for watershed management and resource erosion in Koga watershed using AnnAGNPS model. Calibration of the model was carried from 1988–2001 and validation from 2002–2007. The result of sensitivity analysis indicated that the CN was the most sensitive parameter to runoff and peak runoff rate whereas LS and K-factor were for sediment yield following RF, and these parameters were subjected to calibration. For model calibration, R2 of 0.69, 0.35, 0.55; NSE of 0.69, −0.38, 0.55; RSR of 0.54, 1.14, 0.67; and PBIAS of 0.07%, −80.56% and 4.09% were obtained for surface runoff, peak runoff rate, and sediment load, respectively. Similarly validation results indicated an R2 of 0.76, 0.54, 0.62; NSE of 0.76, 0.38, 0.62; RSR of 0.43, 0.71, 0.56, and PBIAS of 2.31%, −36.58% and 5.68% for surface runoff, peak runoff rate, and sediment load, respectively. Where the model efficiency was rated at the range of fair to excellent for three of the outputs of the model for both calibration and validation period. Only 21.5% of the area was able to generate the 78.8% of total soil erosion, with higher than tolerable limit. Hence converting of 21.5% of highest eroding cropland cells either to forest or grassland would reduce soil erosion, sediment yield and load significantly. Ultimately it would help to reduce the sedimentation in Koga dam which could result in reduction of storage capacity.

Berhanu M. Mekuria, Mamaru A. Moges

Morphological Changes in the Lower Reach of Megech River, Lake Tana Basin, Ethiopia

This study examined and identify, map the plan-form changes and to evaluate, investigate and explore the effect and impact or influence of drivers/catchment process induces for the plan-form changes along a 44.43-km stretch of Lower Reach of Megech River, Lake Tana Ethiopia, for the last 30 years by using secondary climate data, catchment characteristics, field observation, key informant interview and Satellite images of the year 1984, 1995, 2000, 2006, 2009 and 2014. For data preparation and analysis, Image analysis software (ERDAS 2014), Arc GIS and Terrain analysis tools were used. Lower reach of Megech River has undergone major plan-form changes for the past 30 years. At a distance about 19.3 km from the Lake, the river abounded the old channel course and shifted from west to east and developed new channel which directly drains to Lake Tana. The sinuosity of Megech River shows an overall increase of 8.2% for the 30-year study period. Generally, the plan form alteration of Megech River at different reach is due to natural and artificial influences. Hence, appropriate river engineering works should be practiced so as to minimize the negative aspects of channel bank retreats.

Getachew Asmare, Mengiste Abate

Development of Rainfall Disaggregation Model in the Awash River Basin, Ethiopia

This study aims at developing a model that can generate synthetic hourly rainfall data from the existing daily rainfall data of Awash river basin. Fifteen minutes rainfall data collected from national meteorological agency for 13 active stations and daily data collected from 54 stations were considered. Stochastic rainfall disaggregation and Hyetos temporal precipitation model was tested using the available fifteen minutes data. Three regions with close climate condition and rainfall pattern were identified and tested to be homogeneous in the stochastic method. Both methods are tested by using statistical comparison of variance, skew-ness, probability of dry period, and Lag-1 ACF. The result of the stochastic method showed very good performance in preserving the probability of zero rainfall and the daily rainfall total. But it has limitation in disaggregating rainfall magnitudes with high return period. Statistical comparison of Hyetos model indicated very good agreement with the original data. Especially the daily total statistical properties were well preserved. The comparison of the two methods showed that Hyetos is better in preserving the statistical property. Generally the methods are capable in preserving statistical properties and the daily total rainfall depth. Therefore, Hyetos model is pertinent for only temporal disaggregation, whereas the stochastic method is applicable for both spatial and temporal disaggregation in the basin.

Tsegamlak D. Beyene, Mamaru A. Moges, Seifu A. Tilahun

Evaluation of Processing Conditions for Lentil and Corn Blend Extrudate

An expanded food product was obtained from lentil-corn flour mixture by extrusion cooking. The lentil flour addition was maintained at 10%, 30% and 50% mixed with cereal or (corn) flour which was maintained at 50%, 70% and 90%. Operating conditions were cooking temperature; blend ratio and moisture contents of the feed mixture. Physicochemical properties of the extruded product were investigated.The proportions of lentil and corn were selected using a unique 17-run, three-factor, and three-level using response surface methodology. Response variables were physical properties (specific length, degree of expansion and bulk density) and functional properties (water absorption index, water solubility index and water hydration capacity) and then sensory quality of the product.It was demonstrated that lentil has good potential for making extruded products rich in protein and fiber. The best model which gives a protein rich extruded product with desirable physical and functional attributes were 47.8% lentil flour, 52.2% corn flour (db) processed at 15.82% moisture content and 181.97 °C temperature. The product was fully expanded and well cooked with almost uniform in sizes and shapes at these optimum conditions. Hence, the processing factors must be at its optimal values to achieve high extrudate quality and consistence.

Tadesse Fenta, Yogesh Kumar

Machine Repair Problem with Preventive Maintenance and Multi Criteria Prioritization of Machines

Queues of failed machines in machine repairing problem occur due to the failure of machines at random in the manufacturing industries, while different jobs are performed on the machines. Due to failures of machines, the manufacturing system may face significant loss of production, revenue, and customer goodwill. Most existing studies of the machine repair problem founded their study on the assumption of machines are repaired only after failure and with first come first served service discipline. That means preventive maintenance and machine priority based service are ignored. Our study extends this model by incorporating preventive maintenance and multi-criteria based prioritization of machines. Analytical network process tool is used to obtain the priority of machineries. And age based repair differential equations governing the model are constructed. We have established some indices for the system performance in terms of optimal preventive maintenance age t and system’s long run expected cost. An illustrative case is considered to justify solution quality by comparing the result with the previous model study results.

Ahmed Abide, Jeyaraju Jayaprakash, Bereket Haile, Sisay Geremew

Cascaded Hybrid Device Multilevel Converters for Wind Mill Applications

In recent years Multilevel Converter (MLC) plays a vital role in wind power genration. In this paper, Shifted Carrier - Pulse Width Modulation (SC-PWM) based hybrid device multilevel converter configuration for 5 MW wind mill are proposed. A five level cascaded hybrid device MLC is developed and the simulations are performed using MATLAB/Simulink. The simulation results are offered and their performances are analyzed by implementing FPGA SPARTAN-3 processor. The proposed MLC reduces the THD and increases the output voltage.

P. Palanivel, R. Selvarasu, B. Barani Sundaram, Hinsermu Alemayehu

Evaluation of Workplace Environmental Ergonomics and Method Development for Manufacturing Industries

Though workplace safety is relatively satisfactory in developed countries, it does not receive proper attention in developing countries yet. It is known that productivity improvement mainly in labor intensive factories like metal and textile, is not easy without considering the workforce safety. Studies on Ethiopian manufacturing industries show that there are different workplace safety problems, and as a result of less attention, there are also very few practices on prevention and control. Even the few studies done on the area do not yet see the workplace physical factors in terms of complying standards and being causes for injuries and low performance. Thus, this study focused to assess and ergonomically evaluate the workplace environment and develop a control method. It is conducted on purposely selected 10 metal and 4 textile factories. Workplace observation, focus group discussion and measurement are methods applied and digital light, sound level and heat stress meters are measurement equipment used. The factories’ environmental measurements compared to the Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NOISH) standards shows incompliance and even some textile and garment factory work sections has lighting reading level less than 250 lx where 2000 lx is the standard, and metal factory work sections have also up to 128 dB from 85 dB noise exposure standard. Hazardous sections are identified as an intervention and the major causes and impact of the factors is assessed. Finally, a factory level strategic approach model is developed for workplace hazard prevention and control.

Tomas C. Kassaneh, Ahmed A. Tadesse

CSN 12050 Carbon Steel Mechanical Property Enhancement Using Thermal Treatment to Optimize Product Sustainability

Many of the mechanical properties of steel can be improved under controlled sequence of heating and cooling to modify their properties and to meet the desired engineering applications. In this study, the effect of heat treatment cycles (hardening, normalizing, annealing, tempering and recrystallization) on the mechanical properties of CSN 12050 carbon steel have been studied. The aim of the study of this paper is to enhance the ease of machinability for CSN 12050 carbon steel products and to achieve the ultimate goal of product sustainability optimization. The treated and untreated samples change in properties is examined using standard methods. Spectro test TXC25 machine model number 2010, Vickers Hardness tester (HV), and WP310 universal material tester is used to analyze chemical composition and mechanical properties of the specimens respectively. The standard mathematical equations are used to calculate the experimental results of mean values for the test samples of HV and the stress-strain values obtained from the tensile test; later converted to true stress-strain values. Results showed that the mechanical properties of CSN 12050 carbon steel can be changed and improved through annealing and recrystallization process for the ease of machinability. Moreover, the enhanced mechanical properties of CSN 12050 carbon steel can be enlighten the goal of product sustainability through the achieved ease of machinability in dry turning condition.

Melesse Workneh Wakjira, Holm Altenbach, Perumalla Janaki Ramulu

Physico-Chemical Characterizations of Ethiopian Kaolin for Industrial Applications: Case Study WDP Propoxur Formulations

This research aims to investigate chemical, physical, mineralogical and optical properties of Ethiopian kaolin with mechanical, wet beneficiation, chemical modification and thermal treatment (calculations) for their appropriateness of industrial application. The effect of beneficiation and calculation methods of treatment on the structure of kaolin was studied using complete chemical analysis (AAS), X-ray diffraction, Fourier transforms infrared spectrometer analysis (FTIR) and Thermal analysis comparatively with the reference kaolin were studied. Complete silicate analysis showed that the Fe2O3 and TiO2 were reduced via beneficiation and beneficiation with surfactant from 1.908% to 0.201% and 0.87% to 0.056%, respectively. Physico-chemical characterizations, thermal analysis effect of calculations results show that improvement to a very high grade with a chemical composition close to that of ideal kaolin. Beneficiation with a surfactant, followed by calcination at 850 °C, showed a further decrease in Fe2O3 and TiO2 impurities. XRD results revealed that all characteristics reflection of kaolin and quartz were showed as major peaks upon calculations and as well as the reference kaolin. The basic properties for industrial grade specification significantly increased after a certain treatment in comparison with reference (imported) kaolin.

Tadele Assefa Aragaw, Feleke Kuraz

Effect of Biochar Application Rate, Production (Pyrolysis) Temperature and Feedstock Type (Rice Husk/Maize Straw) on Amendment of Clay-Acidic Soil

Biochar is a porous solid material produced by pyrolysis (oxygen-free burning) of biomass for the sake of improving soil quality. The aim of this study was to examine the effect of biochar application rate, pyrolysis temperature and feedstock type on the fertility of leached, acidic, clay soil. The biochars used in the study were produced from rice husk (RH) and maize straw (MS) at pyrolysis temperatures of 350, 450 and 550 °C, so in total six biochars were used. To examine the effects of biochar on soil amendment, the six biochars were mixed with the acidic, clay soil at four different levels of applications (0.5, 2.0, 5.0 and 10.0% w/w) then they were chemically characterized. pH, electrical conductivity, CEC, exchangeable basic cations, WHC, organic carbon and total nitrogen content were determined. The increment in the application rate of biochar resulted in a significant increment in soil pH, CEC, exchangeable basic cations, WHC, Organic carbon content. Increasing the biochar production temperature from 350 to 550 °C brought slight increment in pH, Electrical conductivity and Organic carbon content of the soil. Incorporating RH biochar in the soil resulted in higher soil pH but higher organic carbon content of the soil was acquired by incorporating MS biochar.

Brook Tesfamichael, Nebiyeleul Gessese

Performance Comparisons of Solar Mixed and Indirect Dryers for Maize Grain Drying

This paper presents the design, construction and performance evaluation of mixed (SCMD) and indirect (SCID) -mode solar cabinet dryers for drying of maize grain with varieties of BH-540 and BH-660. The performances of the solar dryers were tested with three levels of sample loading, 21.74 kg/m2 (thick layer), 16.3 kg/m2 (medium layer), and 10.87 kg/m2 (thin layer). In both dryers, the air was heated in the solar collector and passed naturally through a grain bed. For SCMD, the drying cabinet absorbs solar energy directly through the transparent roof. The solar irradiance, temperature and relative humidity distribution for ambient and in different parts of the dryer, and moisture loss of the grain at each try have been recorded. The result revealed that, a temperature raise of 15 °C was found in both dryers with respect to the ambient air. The required drying time was varied depending on the amount of sample loaded. About 32 h was required in thin layer compared to 53 h in thick layers drying process to reduce the moisture content of the grain to its safe storage value of 13% (w,b). The drying rate, collector efficiency and overall system efficiency were varied from 0.41–0.56, kg/h, 44.4–57.2%, and 24.0–32%, for SCID and from 0.47–0.58, kg/h, 44.4–57.2%, and 24.6–33%, for SCMD respectively. Statistically, no significant difference has observed on drying rate and overall dryer efficiency between SCMD and SCID.

Aynadis Molla, Sajid Alavi, Bhadriraju Subramanyam, Solomon Workneh, Nigus Gabbiye

Test and Characterization of Tensile Strength of Oxytenanthera Abyssinica and Yushania Alpina Bamboos

Bamboo has a long and well-established tradition as a building material throughout the world. Bamboo has various applications such as, for furniture, bicycle structure, unmanned air vehicle structure. Despite the fact that Ethiopia has abundance bamboo, till now the tensile strength of both Oxytenanthera abyssinica (solid) and Yushania Alpina (hollow) bamboo was not studied sufficiently. This research focuses on tensile strength testing and characterization of solid and hollow bamboo found in Amhara region at Jawi and Awi district through standard test procedures. The specimens were prepared and tested according to ISO standard. The tensile strength of specimens were tested and characterized with respect to its species, age and culm position. The test result showed that tensile strength of solid and hollow bamboo without node, increases from bottom to top. Hollow and solid bamboo specimens without node had greater tensile strength than specimens with node. Besides solid bamboo without node had superior average tensile strength (ranges between 211.5 MPa to 260.2 MPa) than hollow bamboo without node (179.7 MPa to 246.1 MPa). Irrespective of the age, specious, with node and without node the lowest strength showed on the bottom portion of the specimens. The test specimen results demonstrated as the age increases from year two to four, the bottom strength increased consistently. To use bamboo for structural and related purpose it is recommended to take the bottom portion strength than the average or the highest strength for safe design.

Fentahun Ayu Muche, Yonas Mitiku Degu

Effects of Soil and Water Conservation Practices on Runoff, Soil and Nutrient Losses in Alekt Wenz Watershed, Ethiopian Highland

Land degradation caused by soil erosion is a serious problem in northwestern Ethiopian highlands. To reduce the adverse impact of land degradation, soil and water conservation (SWC) measures were implemented. The presented study investigated the hydrological responses of SWC measures implemented in two nested watersheds situated in the northwestern Ethiopian highland. Rainfall, streamflow, sediment concentration, and sediment-associated and dissolved nutrient of N and P for 2015 and 2016 rainy periods were collected and analyzed. The watersheds received 665 mm in 2015 and 795 mm rainfall in 2016 from May to September. The median infiltration rates for treated and untreated watershed were 22 mm hr−1, and 19 mm hr−1 respectively. The direct runoff from treated watershed was 8.5 mm yr−1 for 2015 and 9.6 mm yr−1 for 2016. This is lower than the untreated watershed, which responded 17.3 mm yr−1 for 2015 and 15.3 mm yr−1 for 2016. The base flow from treated watershed was 180.7 mm yr−1 for 2015 and 212 mm yr−1 for 2016. It was higher than the untreated watershed, which responded 69.8 mm yr−1 for 2015 and 195.4 mm yr−1 for 2016. This figure shows that implemented SWC measures reduced the runoff responses by two-fold. Similarly, the SWC measures reduced sediment yield. The sediment yield from treated watershed was 2.4 ton ha−1yr−1 and 2.1 ton ha−1yr−1 in the year 2015 and 2016, respectively. This is lower than the untreated watershed that lost 6 ton ha−1yr−1 and 8.5 ton ha−1yr−1 in the year 2015 and 2016, respectively. The effectiveness of the SWC measures between the two watersheds was statistically significant with a significance level of 5%. However, it is important to investigate the long-term effects of SWC in reducing soil and nutrient losses.

Simir Birihan Atanaw, Dessalew Worku Aynalem, Anwar Assefa Adem, Wolde Mekuria, Seifu Admassu Tilahun

Optimization of Green Logistic Distribution Routing Problem with Multi Depot Using Improved Simulated Annealing

The traditional vehicle routing problems (TVRP) are suited for cost minimization. In this study, Green VRP with Multi Depot (G-VRPMD) is addressed. The G-VRPMD, an extension of TVRP, is NP-hard which creates eco-friendly distribution system starting and destination to multiple depots. In the present study, modified probability of accepting criteria (MPAC) has been developed. Clustering of consumer was done based on nearness’ to depot using distance saving method. Depot’s number, customer number and optimal distance used as performance measures. Comparison of output result with state-of-the-art shows that the performance of Improved Simulated Annealing (ISA) is effective in solving G-VRPMD. The emission rate is proportional to age; therefore in designing distribution network path has to incorporate vehicle age prior to optimization.

Teshome Bekele Dagne, Jeyaraju Jayaprakash, Bereket Haile, Sisay Geremew

Failure Mode Analysis of Automotive Final Drive Gears

After repeated complaints from customers about failure, the crown and pinion assembly of the vehicle was analyzed by standard metallurgical methods. Standard material composition of the part was confirmed by chemical analysis. Tooth contact analysis was done to understand the contact and sequence of failure. Micro hardness test was done to understand about the hardness of the specimen. The nature of fracture is studied by subjecting the specimen to micro-structural study. It was found that the effect of combination of low case hardness and improper composition was augmented by improper alignment while assembling caused premature failure of the component.

Rajesh Murukesan, Teshome Dengiso Megiso

Design, Fabrication and Testing of Animal Drawn Multiple Mouldboard Plough

The Ethiopian Ard plough is the most commonly used farm tool in Ethiopia. Nevertheless, using this plough as farm tool is labour intensive, time taking, making shallow depth and narrow cutting width. Thus, this research is initiated to come up with a solution to the aforementioned problems. Therefore, the objectives of this research were to model the basic components of animal drawn multiple mouldboard plough, to fabricate and test the prototype. Eight alternative options were considered for conceptual design among these, without seat to operator, two wheels, two handles and beam attachment design alternative is selected using merit-demerit analysis, pairwise and direct matrix ranking methods. In addition, after the detail design, the prototype is fabricated in Bahir Dar University Institute of Technology Workshop using locally available materials and tested using oxen and horses as draft animals in two most dominant soil types such as Nitrosol and Vertisols at Burie and Gozamin districts of East and West Gojjam Zones of Amhara regional state respectively. The results of the field test reveals that there is a significant difference between Ard plough and the newly designed prototype in time requirements to plough the same plot of land, draft force requirements and cutting width. The newly designed prototype reduces time spent and increasing cutting width during primary tillage. The draft force requirement of both Ard plough and multiple mouldboard plough is higher at Nitrisols than Vertisols. The multiple mouldboard plough cut of width and depth can be adjusted to go along with the available draft animal for optimum field operation performance.

Abebe Firew Guadie, Yonas Mitiku Degu

Design, Construction and Testing of Hybrid Solar-Biomass Cook Stove

Many investigations have been conducted in biomass stoves to improve performances and minimize unfavorable effect on both human health and global climate. Solar cookers are also great area of investigation which can cook food without burning any wood. But a solar cooker cannot replace the traditional energy source completely; even in the sunniest regions there will be days and hours the sun doesn’t provide enough power to cook meal. Recent researches and investigations are focused on improving the efficiency of existing only biomass or only solar cookers and there is a research gap in combining solar and biomass for cooking. A combined cook stove is another research dimension for intervention with an intention of using the benefit of the free solar energy to save biomass fuel. In this work, design, fabrication, and testing of portable solar-biomass combined cook stove have been done. The test was done by using only biomass, only solar and combined energy sources for cooking. The results show that the biomass stove with reflectors under the sun gives a 5% thermal efficiency rise and 6 g/L reduction in fuel consumption when compared to the only biomass stove. When only solar box oven used the first figure of merit was found to be 0.12 and second figure of merit found to be 0.55.

Bisrat Yilma Mekonnen, Abdulkadir Aman Hassen

Design and Analysis of Low-Transition Address Generator

In high-speed Nano-scale VLSI designs, memory plays a vital role of operation. Built-In Self-Test (BIST) for memory is an essential element of the system-on-chip (SoC). Investigating memory with low power techniques have been emerging in the market. Address generators to access memory cores consecutively should have low transition. This paper, attempted to put forward a proposed architecture of address generator with low-transition. In this novel technique, the address generator is constructed by a blend of modulo-counter and binary to gray code convertor with a bit-reversal block. Efficient employment of this architecture has cut-down the switching activity considerably. This proposed work compared the switching activity with conventional Linear Feedback Shift Register (LFSR), Bit-Swapping LFSR (BS-LFSR) and gray-code generator. Simulated and synthesized of the proposed architecture was done by Xilinx tool. The final result shows more than 95% reduction on dynamic power consumption related to the traditional LFSR.

Sivasankaran Saravanan, Mikias Hailu, G. Mohammed Gouse, Mohan Lavanya, R. Vijaysai

Modeling of Induction Heating Inverter Using System Identification

In this paper, Auto Regressive eXogenous input (ARX), Auto Regressive Moving Average eXogenous input (ARMAX), Output error and BJ models of class D voltage-source half-bridge series-resonant inverter used for induction heating are identified and studied based on prior knowledge and measured data from PSIM simulation Environment. The output data are generated by applying Pseudo-Random-Binary-sequence (PRBS) as an input through the inverter MOSFET gate in the PSIM software. PRBS signal is generated using standard components such as flip-flops or XOR gates to approximate the white noise in the PSIM software. The generated output and input data are loaded in the MATLAB to identify the unknown system parameters of induction heating inverter by using MATLAB system identification toolbox. Estimation of models with pre-selected structures can be performed using system identification toolbox. To validate the models and their limitations, the fitness properties of the models based on percentage best fit and their resonant frequencies are examined.

Mulugeta Debebe, Endalew Ayenew, Beza Neqatibeb, Venkata Lakshmi Narayana Komanapalli

Development of Low Cost Gemstone Polishing Cum Cutting Machine

Ethiopia has many types of natural resources that can be exported and brought high foreign currency; which can help to improve the financial status of this country. However; one of these resources is gemstone minerals, which is mostly preferred for jewelry purpose globally; due to its unique attraction, properties and natural behavior. Moreover; very expensive gemstone like opals, emerald, ruby, sapphire, etc. are available in this country in a huge quantity. However; these natural resources exported in raw form without post processing to the other developed countries to bring high foreign currency. Nevertheless; due the export presently we are not getting good returns on this export. By considering this fact gemstones processing jobs has been started in Amhara region of Ethiopia to add values and to increase the selling price of it. Hence present study focuses on the “Development of low cost Gemstone polishing cum cutting machine for further value addition of gemstone mineral. Mostly the available machines for gemstone processing globally are very expensive; therefore in the present study the efforts are taken to use the indigenous materials as alternatives to develop the low cost gemstone processing technology. This development work endorsed the dramatic cost reduction of the machine imported from abroad by saving more than 50% total cost.

Fetene Teshome, Kishor Purushottam Kolhe

Kinetic Modeling and Gas Composition Analysis During Sawdust Pyrolysis

This research paper deals about kinetic modeling and gas composition analysis of sawdust pyrolysis. The thermal degradation of sawdust at lower (10 ℃/min), medium (20 ℃/min) and higher (50 ℃/min) heating rates were conducted using Beijing Henven Thermo Gravimetric (TG) analyzer. The sawdust pyrolysis gave 98% gas and 2% char, 80% gas and 20% char, and 70% gas and 30% char for lower, medium and higher heating rates. The Flynn-Wall Ozwa (FWO) model free method and the Arrhenius equation was used to estimate kinetic parameters and rate of this pyrolysis process. The rate equation was 93% fit with the medium heating pyrolysis data, which was better fit than the other heating rates. The Thermo Gravimetric analyzer and Jesco 6600 Fourier Transform Infrared (FTIR) analyzer were connected and the released gases at medium heating were investigated. Using TG-FTIR analysis carbon monoxide, carbon dioxide, water, hydrogen and char were released during pyrolysis of sawdust at medium heating rate.

Tesfaye Alamirew, Solomon W. Fanta

Evaluating the Role of Runoff and Soil Erosion on Nutrient Loss in the Chenetale Watershed, Upper Blue Nile Basin, Ethiopia

The non-point source pollution of agricultural nutrients (P and N) by surface water is not well quantified in the Ethiopia highlands. The objective of this study was to quantify soil nutrients (N and P) from an agricultural uplands area in upper Blue Nile basin. A small watershed (104.6 ha) and nested gully catchment were gauged for data collection. Two years (2015 and 2016) data of runoff, sediment, sediment-associated and dissolved soil nutrients loss were collected from two gagging stations. Both dissolved and sediment associated nutrients were computed for 2015 and 2016 rainy seasons. The result indicated that sediment associated nutrient loss was significantly higher than the dissolved nutrient loss. In 2015, the nutrients loss was 8.93 kg ha−1yr−1 N and 0.3 kg ha−1yr−1 P at the outlet of W-1 and 3.04 kg ha−1yr−1 N and 0.14 kg ha−1yr−1 P at the outlet of W-2. In 2016, 7.67 kg ha−1yr−1 N and 0.24 kg ha−1yr−1 P were lost at the outlet of W-1 and 8.44 kg ha−1yr−1 N and 0.57 kg ha−1yr−1 P were lost at the outlet of W-2. Nutrients losses with sediment were 91.3% and 45.6% of N and P, respectively. High amount of nitrogen was lost with sediment than in dissolved form indicating that soil erosion is an important process for soil nutrients losses in the highland. Therefore, soil and water conservation practices are practically significant to control soil nutrients loss.

Alemsha G. Bogale, Dessalew W. Aynalem, Anwar A. Adem, Wolde Mekuria, Seifu A. Tilahun

Adaptive Cloudlet Scheduling Algorithm Using Three Phase Optimization Technique

The purpose of cloud computing is to give suitable access to the remote scattered resources. This is achieved through virtualization, which separates the physical computing resources into multiple virtual resources. The other technologies like grid, utility and distributed computing are the backbone of cloud computing. The scheduler plays important role because the user has to pay for the resource based on the time consumed during their usage. Currently, cloudlets and the virtual machines are scheduled according to FCFS and round robin which has higher latency. In order to reduce the latency and to have uniform distribution in scheduling the cloudlets to the Virtual Machines, this paper introduces called ACS3O algorithm which consists of 3 phases of optimization techniques using gang and dedicated processor scheduling to schedule the cloudlets. The proposed cloudlet scheduling algorithm optimizes few basic parameters like waiting time and makespan which have significant impact in the performance. Simulation is done in a Cloudsim environment to evaluate the proposed algorithm.

Mohan Lavanya, B. Santhi, Sivasankaran Saravanan

Design and Development of Household Gasifier Cooking Stoves: Natural Versus Forced Draft

In recent years, there has been renewed interest on renewable biomass based energies. This is due to the growing environmental stringent regulation, energy security concern and spiraling price of fossil fuel. More than 80% of the Ethiopian population who reside in the rural depend on biomass energy for their cooking and lighting. Traditionally, food cooking and Injera baking are carried out using an open fire/three stone/system in the rural areas. Despite the substantial effort made by Ethiopian government to disseminate improved biomass cooking stove technologies such as Mirt, Lakech, Tikikil, and Gonzie, the end of pipe technological use strategy is very minimal. In this study rigorous natural and forced draft gasifiers stove design were performed based on energy consumption load for cooking and solid waste management purposes. Standard water boiling test (WBT) and controlled cooking test (CCT) were used to determine the performance of the stove. The WBT showed that the gasifier stove had thermal efficiency of 22.7% and 25% for natural draft and forced draft respectively. Moreover, the CCT indicated that the performance of the gasifier stove were 84% and 72% for natural draft and forced draft as compared to the traditional open fire three stone stove. The burning time using 0.8 kg of fuel was 65 min and 40 min for natural and forced draft gasifier stoves respectively.

Eshetu Getahun, Dawit Tessema, Nigus Gabbiye

PSNR and Robustness Comparison Between DCT and SVD Based Digital Image Watermarking Against Different Noise and Attacks

This paper presents a comparison of extracted watermark image quality and robustness between DCT and SVD based digital watermarking techniques. Here two transform domain DCT and SVD based watermarking algorithms are implemented. For better comparison purpose original host image and watermark image are kept same in both algorithms. Before extracting watermark, different image processing attacks and noise are inserted in watermarked image then DCT and SVD based watermark extraction are performed to check PSNR and robustness against those image processing attacks and noise. Obtained experimental results show that between these two algorithms, robustness, and quality of extracted watermark images are better in SVD based watermarking method.

Tarun Rathi, Rudra P. Maheshwari, Manoj Tripathy, Vikas Chaudhary

Multi-font Printed Amharic Character Image Recognition: Deep Learning Techniques

In this paper, we propose a technique to recognize multi-font printed Amharic character images using deep convolutional neural network (DCNN) which is one of the recent techniques adopted from the deep learning community. Experiments were done on 86,715 Amharic character images with different level of degradation and multiple font types. The proposed method has fewer pre-processing steps and outperforms the standard approach used in classical machine learning techniques. We systematically evaluated the performance of the recognition model and achieved 96.02% of character recognition accuracy.

Birhanu Hailu Belay, Gebeyehu Belay, Tewodros Amberbir Hebtegebrial, Didier Stricker

Modeling and Control of Electro-Hydraulic Actuator

Modeling and position control of an Electro-Hydraulic Actuator (EHA) system is investigated in this paper. Linear ARX EHA system model is identified by taking the experimental data using system identification toolbox in the MATLAB/Simulink. From the identified models the best fit ARX 331 model is used to design a controller using fuzzy logic and Particle swarm optimization (PSO) methods. In the self-tuning Fuzzy PID controller, the controller parameters KP, KI, and KD are tuned by the fuzzy controller depending on the two inputs: error and derivatives of the error. In the PSO optimized PID controller, the sum of the time-weighted absolute error objective function is minimized and optimized controller parameters are tuned using PSO algorithms. The results are simulated in the MATLAB/Simulink and compared among conventional Ziegler-Nichols (Z-N), Fuzzy, and PSO PIDs. The results indicate that the self-tuning fuzzy PID and PSO optimized PID give better performance than the Z-N PID controller and the PSO-optimized PID controller demonstrates superior performance in terms of percentage overshot and speed of response with 5% overshoot, 0.02 s rise time and 0.15 s settling time.

Beza Nekatibeb, Venkata Lakshmi Narayana Komanapalli, Mulugeta Debebe, Endalew Ayenew

Wind Energy Conversion System Model Identification and Validation

Wind energy conversion system (WECS) is complex because of wind speed varies in time and space. Model identification is required to represent its dynamics for real-time implementation. In this paper a doubly-fed induction generator (DFIG) WECS is used. Different model structures are generated and simulated using MATLAB/SIMULINK. The models are generated using both nonlinear and linear system identification tool boxes. Linear system identification toolbox generates both model structure and model parameters; whereas the nonlinear system identification tool generates only the system model structures. From linear models, the BJ33221 model has better performance with best fit of 74.78%, final prediction error (FPE) value of 0.0445 and mean square error (MSE) is 0.04265. ARX211 model structure provides best fit of 74.39%, FPE of 0.0453, and MSE is 0.04465. This study shows as model order increases, the best fit value too, but the system become more complex. The nonlinear models have better performance than the linear models. The nlarx121 model structure provides the best fit of 96.43% and MSE of 0.0322, with other technique for its model parameters estimation. The output residuals are within the confident range (0.2 to −0.2), indicating the model structure was validated.

Endalew Ayenew, Mulugeta Debebe, Beza Nekatibeb, Venkata Lakshmi Narayana Komanapalli

Evolutionary Based Clustering Protocol for Wireless Sensor Networks

Many cluster based routing protocols have been developed in order to enhance the network lifetime, but the potency of clustering in energy management highly relies on the optimality of clusters. Optimal cluster formation is the chief source of challenges in clustering protocols. In this paper, new approach has been introduced to formulate the optimization problem in the partition of networks into optimal organization of clusters. The optimization problem consists of finding optimal configuration of clusters such that the distance of cluster heads from the pre-computed cluster centers, communication cost of nodes to transport data and the expected energy dissipation of the network per the residual energy of cluster heads are minimized. The solution to the devised nonlinear clustering problem is found using the genetic algorithm. The genetic algorithm toolbox is developed in C++ and integrated with OMNeT++ simulation platform to implement the protocol. The experimental results verify that the proposed protocol extends the network lifetime compared to the prominent LEACH, LEACH-C and CHEF protocols.

Melaku Tamene, Kuda Nageswara, Ravuri Daniel

SMS Based Agricultural Information System for Rural Farmers

Agriculture is the back bone of Ethiopia’s economy. Despite the strength and volume of agriculture related information and training available through Ethiopia’s vast public extension system, ensuring farmers receive up-to-date data and knowledge in a timely, complete and quality manner remains a great challenge. The existing practice for delivering agricultural information through agricultural extension officers, farmer-to-farmer visit and mass Medias couldn’t satisfy the information needs of rural farmers. This is attributed by few numbers of extension officers, budget bottle neck and absence of electricity and network. This paper presents a SMS based agricultural information system (SMSbAIS) aimed to solve such challenges in agricultural sector. The SMSbAIS was developed based on a conceptual framework, developed during the course of this research, is used as a platform where rural farmers and agricultural extension officers can get agricultural knowledge service, request agricultural information and supply any information that demands the intervention of higher agricultural officers. It helps users not only to request for agricultural information; it also used to deliver such information to the hands of users via their mobile phones. The system is developed using Rapid Application Development (RAD) methodology with a series of iterative development and testing is done based on System Usability Scale (SUS) method. Testing and evaluation is targeted the systems usability, accuracy and performance. Therefore, it was found that on the SUS scale that ranges from 0 to 100, the system scored 87.6 with feedback from 20 users. The Query Understanding engine (QUE) accurately translated 90% of all incoming user requests. The mean average response system time is found to be 3.34 s. These results show that problem of lack of appropriate and easily accessible agricultural information can be solved using a system like the one developed in this research based on a framework that seeks solutions to challenges faced in accessing agricultural information in rural community.

Alemu Kumilachew Tegegnie, Tekeste Demessie Dagne, Tamir Anteneh Alemu

Review on Dynamic Stall Control in Airfoils

Dynamic stall is a process that occurs when the angle of attack of airfoils exceeds the critical value which leads to fluctuation of aerodynamic loads and loss of performance of streamlined bodies like wind turbines and helicopters as a result of boundary layer separation. This review presents dynamic stall control methods in the oscillating airfoil. Airfoil shape modification and momentum blowing on a boundary layer were the focus of this paper. From the review, it was found that making the leading edge of an airfoil to change its shape dynamically, can help to alleviate dynamic stall in different flow conditions. Similarly, energizing the boundary layer of the flow by momentum blowing both steadily and unsteadily was found to be effective in dynamic stall control while the latter was superior. From the review, it was shown that whatever methods were applied to control dynamic stall, the effectiveness of those methods depend on other parameters too like reduced frequency.

Abraham Adera, Siva Ramakrishnan

Simulation Study of Inventory Performance Improvement in Consumer Products Trade Business Unit Using System Dynamic Approach

This paper focused optimal inventory study on multi-product, multi-period, perishable products replenishment quantity in consumer product trade business unit (CPTBU) warehouse in Bahir Dar city. We proposed system dynamics method to improve optimal replenishment quantity of expired and stock-out products and saved the total operation cost such as loss of sale, expired cost, holding cost and ordering cost using vensim software. This study proposed 34.7% improved replenishment quantity of expired products, 32.2% replenishment quantity of stock-out products and totally this proposal saved 43,000US$(1.2 million birr) of operational cost per year.

Maseresha Agumas, Jeyaraju Jayaprakash, Melkamu Teshome

Optimized Secure Scan Flip Flop to Thwart Side Channel Attack in Crypto-Chip

Present crypto based smart systems very popular for secure application. But all this system was targeted by various threats, malfunctions, hacking and side channel attack. Cryptography algorithm will try to give secure in data encryption and decryption but failed in direct hardware implementation. This paper provides an optimized secure testing method against side channel attack in crypto chips. This proposed system reduces the switching activity in latches and also reduces the power consumption in architecture. It avoids unwanted latches to obtain optimization in area by random insertion of scan chain design. This optimized architecture was targeted to RSA crypto algorithm to show the effectiveness of the proposed method over various existing methods.

Sivasankaran Saravanan, Mikias Hailu, G. Mohammed Gouse, Mohan Lavanya, R. Vijaysai

Inbound Multi-echelon Inventory Supply Network Model in Ethiopian Leather Industry: A Simulation Study

Leather processing companies are highly affected due to irregular availability of raw hide and skin by trends of globalization and dynamic behaviour of meat usage in Ethiopia. Maintaining optimal inventory stock in inbound multi-echelon supply networks is more complex in nature due to high fluctuation of raw materials availability. This paper presents a deterministic optimal procurement inventory policy among four designed inventory replenishment strategies in the tanning industries to avoid fluctuation raw materials. We proposed simulation model for these four different procurement strategies of raw materials in each inbound multi-echelon supply network. After running the trial simulation, a significant method of controlling the inventory level in the tanneries while keeping the operating performance in a reasonable level is achieved. The outputs are analyzed using ARENA simulation inventory stock information in every tier of the supply chain network. Finally simulated outputs of these strategies in each level are compared with performance using analytic hierarchy process (AHP) a multi-criteria decision model.

Robel Negussie, Jeyaraju Jayaprakash

Efficient FPGA Implementation of an Integrated Bilateral Key Confirmation Scheme for Pair-Wise Key-Establishment and Authenticated Encryption

The purpose of this paper is to propose a bilateral key confirmation scheme which provides a trustworthy key establishment between two communicating parties. There are various cryptographic schemes proposed based on unilateral key confirmation. But, such schemes do not confirm the equality of the common secret information computed independently by each communicating party, and do not consider whether the other end is the intended owner of the shared secret. However, exchanging of the secret information blindly without verifying that both of the ends have computed the same common secret information and without ensuring the identity of the other end with whom they are communicating, can create security risks since attackers can impersonate acting as a claimed sender or recipient. The proposed work provides bilateral key confirmation for pair-wise key-establishment based on FPGA by integrating a key agreement protocol and an authenticated encryption scheme. The implementation outcomes show the proposed scheme’s reasonable hardware complexity and enhanced performance compared to existing similar works.

Abiy Tadesse Abebe, Yalemzewd Negash Shiferaw, Workineh Gebeye Abera, P. G. V. Suresh Kumar

Spatial Analysis of Groundwater Potential Using GIS Based Multi Criteria Decision Analysis Method in Lake Tana Basin, Ethiopia

Groundwater resource development for various uses is increasing in the Lake Tana basin, as surface water became limited in quantity and quality. Assessment of the groundwater potential (GWP) in the basin is crucial for sustainable use of water resources. This study aims at assessing the GWP in the basin using remote sensing and GIS-based Multi Criteria Decision Analysis (MCDA). Seven factors (lithology, lineaments, drainage density, rainfall, slope, land use/land cover and soils) that affect groundwater distribution were considered. Analytical Hierarchy Process (AHP) approach were used to compute each layer weight. Thematic weighted layers were overlaid in ArcGIS to identify GWP are-as in the basin. The result indicated that, 15% (1765 km2) classified as “very high”, 26.5% (3151 km2) as “high”, 31% (3592 km2) as “medium”, and 27.5% (3224 km2) were classified as “low” GWP zones in the basin. The GWP map was validated using observed borehole and springs data in the basin, and it indicated that 76% of agreement. It was found that GWP was highly sensitive to lithology and rainfall with mean variation index of 2.7% and 2.0%, respectively. High GWP is available at the southern and eastern side of the Lake Tana.

Agumase T. Kindie, Temesegen Enku, Mamaru A. Moges, Berhanu S. Geremew, Haimanot B. Atinkut

Hydrothermal Synthesis of Na-P1 Zeolite from Pumice to Enhance Moisture Content and Water Retention Capacity of Sandy Soil

In this study, pumice as a precursor from Semen Shoa, Minjar Shenkora Woreda was used in synthesis of Na-P1 zeolite. Hydrothermal treatment was performed with sodium hydroxide at different ratio of pumice to NaOH pellets (1:1.2, 1:1.5 and 1:1.8) at varying temperatures of 60, 80 and 100 °C and reaction time of 70,100 and 130 min. Effect of pumice to NaOH ratio, reaction temperature and reaction time on Si/Al ratio of synthesized zeolite was studied. Optimal silica to alumna ratio of 2.5 was obtained at temperature of 100 °C, reaction time of 100 min and pumice to NaOH ratio of 1:1.5. Na-P1 zeolite obtained at optimum operating conditions was used for other characterizations such as FTIR, XRD and surface area analysis and for the moisture testing & pressure plate extractor testing. The surface area for this zeolite was found to be 56.04 m2/g. The XRD patterns of the synthesized material after formation of zeolite Na-P1 was observed through reflections on 2θ = 19.31°, 23.44°, 28.32°, 32.43°, 33.5° and 49.10o. The synthesized zeolite showed the most prominent reflection peak at 32.43°. Effects of different dozes of the synthesized zeolite on sandy soil moisture content and water retention capacity were studied. As the dose of zeolite increased from 0 g/kg to 20 g/kg, the rate of moisture loss from sandy soil decreased. The results showed that application of zeolite to the sandy soil significantly increased the moisture content in the mixtures of soil-zeolite. The water holding capacity of the amended soil was tested using pressure plate extractor at 1, 3, 5 and 15 bars. At 0 bars, all soil samples were observed to have the same water content since at the beginning all soil samples had been moistened with water (70% by weight. Then at 1 bar sandy soil without zeolite had a moisture content about 12% whereas sandy soil with 10 g/kg had 15.65%. As the amount of zeolite added increased from 10 g/kg to 15 g/kg and to 20 g/kg, it was observed that adding zeolite on the sandy soil increases the water retention capacity of the soil.

Yonas Desta, Nigus Gabbiye, Agegnehu Alemu

Spectrum Sensing Using Adaptive Threshold Based Energy Detection for LTE Systems

The rapid growth of wireless communication system has put pressure on radio spectrum usage. Due to the widely used fixed spectrum access, spectrum utilization is very low. In order to overcome this problem, cognitive radio (CR), which leads the way for dynamic spectrum access capability is necessary. CR listens to the channel and enables to access unused spectrum of the primary user (PU). The detection decision would be done by either a single secondary user (SU) or by multiple SUs cooperating with each other. Adaptive threshold based energy detection (ED) is the proposed detection technique in which the received signals SNR will be estimated by the SUs using minimum mean square error (MMSE) estimator and if SU is not efficient enough to detect the idleness of the channel due to the reception of weak signal, the SUs will cooperate to detect the PU signal. The simulation results indicate that the proposed system yields much better detection performance both at low and high SNR values.

Hiwot Birhanu, Yihenew Wondie, Fikreselam Gared

Evolving 3D Facial Expressions Using Interactive Genetic Algorithms

Interactive Genetic Algorithms (IGA) are applied in optimization problems where the fitness function is fuzzy or subjective. Its application transcends several domains including photography, fashion, gaming and graphics. This work introduces a novel implementation of Interactive Genetic Algorithm (IGA) for evolving facial animations on a 3D face model. In this paper, an animation of a facial expression represents a chromosome; while genes are equivalent, depending on the crossover method applied, either to a keyframe point information (f-curve) of a facial bone or f-curves of grouped sub-parts such as the head, mouth or eyes. Crossover techniques uniform, cut-and-spice, blend and their hybrids were implemented with a user playing fitness function role. Moreover, in order to maximize user preference and minimize the user fatigue during evolution, sub-parts based elitism was implemented. Subjective measurements of credibility and peculiarity parameters among a given artist animated and evolved expressions were done. For the experiment results here, an average crossover percentage of 85%, a mutation level of 0.01, initial population of 36, and 8 rounds of evolution settings were considered. As detailed in the experiment section, the IGA based evolved facial expressions scored competitive results to the artist-animated ones.

Meareg Hailemariam, Ben Goertzel, Tesfa Yohannes

Comparative Study of Modulation Techniques for 5G Networks

Fifth Generation (5G) communication systems applications are expected to use or require lower latency, higher data rates, and efficient spectrum usage which are impacted by the adopted modulation scheme. Thus, proper selection and usage of efficient modulation scheme is crucial. Orthogonal Frequency Division Multiplexing (OFDM) suffers from high peak to average power ratio, which results in low efficiency of power amplifier and increases the battery consumption. Moreover, the OFDM spectrum has high out of band side lobes or side lobe leakage causing problem of low spectral efficiency. So, to overcome some of these drawbacks new modulation techniques for 5G communication systems such as Generalized Frequency Division Multiplexing (GFDM), filtered – OFDM (f-OFDM), Universal Filtered Multi-Carrier (UFMC), Filter Bank Multi-Carrier (FBMC) are considered. In this paper, we perform the comparative study of UFMC and FBMC in terms of Spectral Efficiency (SE) and Power Spectral Density (PSD). Simulations were done to evaluate the performance variation that can be achieved by varying the parameters of these modulation techniques, such as filter length, burst duration and overlapping factor. Our simulation results show that, FBMC has better SE for large burst durations whereas UFMC is better for small burst durations. In terms of PSD, FBMC has lower side lobe than UFMC. This implies that FBMC is more preferable to minimize the inter symbol interference and inter carrier interference.

Getachew H. Geleta, Dereje M. Molla, Kinde A. Fante

Phytoremediation Potential of Free Floating Plant Species for Chromium Wastewater: The Case of Duckweed, Water Hyacinth, and Water Lilies

Chromium is the second most toxic metal in groundwater, soil, and sediments. Due to its large scale industrial utilization, it exist in various forms in the environment. The present technologies used to eliminate chromium are too expensive and not eco-friendly. Phytoremediation, which is low cost and eco-friendly technology for wastewater treatment was analyzed via Aquatic free-floating plants. This study was conducted to check the phytoremediation capability of three free-floating aquatic plants: Duckweed, Water lilies, and Water hyacinth for the removal of chromium (III) and (VI) in aqueous solutions. The aquatic plants were put in 15 L solution containing 1, 5, and 10 mg/L of Cr (III) and Cr (VI) for 14 days after two weeks acclimation period. The relative growth, tolerance index and chromium uptake by the three plants were measured. The concentrations of chromium in the samples were analyzed using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The results showed a significant increase (P < 0.05) in accumulation of chromium in the plant’s tissues. Maximum total accumulation of 322.57 and 82 mg/kg for plant treated with 10 mg/L for both solution of Cr (III) and Cr (VI) were obtained in Water hyacinth as compared to Duckweed with maximum accumulation of 169.43 and 37.29 mg/kg at 10 mg/L for both Cr (III) and Cr (VI) respectively. Water lilies show a relatively low removal performance with a maximum uptake of 160.82 and 28.78 mg/kg at 5 mg/L for both Cr (III) and Cr (VI) respectively. The relative growth of all plants increase with time but decrease for an increase in concentration of chromium. The study showed that Water hyacinth as an efficient candidate for phytoremediation of chromium compared with Duckweed and Water lilies.

Samuel Gemeda, Nigus Gabbiye, Agegnehu Alemu

Rainfall-Runoff Process and Groundwater Recharge in the Upper Blue Nile Basin: The Case of Dangishta Watershed

For planning, development and management of water resources, understanding runoff mechanism and groundwater recharge is useful especially to watershed management and groundwater use for domestic and irrigation water supply. During the period of the study, stream flow, groundwater levels, infiltration tests, rainfall and soil moisture measurements were conducted. The result from these measurement showed that saturation excess runoff were dominant in Dangishta watershed while infiltration excess runoff also contributes in some parts of the upslope area. This result was also corroborated by better correlation of (R2 = 0.82) at the main outlet than upstream sub watershed outlet (R2 = 0.56) using SCS runoff equation. The result from groundwater level measurement using water table fluctuations approach showed that the total annual groundwater recharge were found to be 400 mm (i.e. 24% of the total annual rainfall) which is a significant amount likely because of the interflow processes to each well.

Abdu Yimer Yimam, Ayele Mamo Bekele, Prossie Nakawuka, Petra Schmitter, Seifu Admasu Tilahun

Testing the Bending Strength of Solid Bamboo and Hollow Bamboo Particleboard

The aim of this study is to test experimentally and determine the bending strength of a particleboard made from hollow and solid bamboo chip composition with urea formaldehyde. The particle board is manufactured at Ethiopian Chip Wood And Furniture Share Company in Addis Ababa. The ratio of solid bamboo to hollow bamboo is 75/25, 25/75, and 50/50 respectively with urea formaldehyde. The bending strength of 75% hollow bamboo (HB) and 25% solid bamboo (SB) is 32.13 MPa and eucalyptus particleboard (EPB) bending strength is 30.63 MPa. The bending strength of 75/25 SB/HB is 159 MPa. The bending strength of 50/50 HB/SB is 30.80 MPa and the bending strength of eucalyptus particleboard is 30.63 MPa. The test results show that the bending strength of bamboo particle board is greater than the bending strength of eucalyptus particle board, and these boards can be used instead of eucalyptus particleboards. Based on the result of the study, bamboo can be recommended as a raw material.

Melak Misganew, Nehemiah Peddinti

Investigations of the Influence of Fiber Orientation on Strength Properties of Agrostone Composites

Agrostone is a construction material and a substitute for concrete that used as an exterior wall and interior partition. It is composed of Magnesium Oxide Powder (MgO), Magnesium Chloride (MgCl2), Bagasse, Glass fiber and Pumice. The Agrostone panel has improved damage tolerance, environmental resistance, fire resistance, and recyclability, good strength, lightweight and potential for fast processing. However, the influence of fiber orientation on tensile, compressive and bending strength of agrostone panel is not studies from the previous researchers. The aim of this experimental study is investigate the influence of different fiber orientation arrangements on tensile, compressive and bending strength of agrostone panel. The testing specimens for experimental analysis prepared by hand layup process using a mixing ratio of 1.5 kg Magnesium oxide Powder (MgO) and 2 L Magnesium Chloride (MgC12). Waste recyclable bagasse 0.15 kg, 0.065 kg Fiber Glass and 0.2 kg of Pumice based on ASTM standard D 3039/D 3039M for tensile testing, D 3410/D 3410M – 03 for Compressive testing and D 790 – 02 for Flexural testing at 0°, 45°, 90°, cross and random arrangement are prepare. From the experiment, the tensile, compressive and bending result of 0° is higher than the other arrangements that has the value of 191.87 MPa, 178 MPa and 181 MPa respectively, therefore it means 0° fiber orientation give a better strength values in general for tensile, compressive and bending loading as compare to others.

Ephrem Zeleke, Mulugeta Eshetu, Taye Meheretu, Mehiret Betemariam, Samuel Melkamu

A Comparative Analysis of Watermarked and Watermark Images Using DCT and SVD Based Multiple Image Watermarking

In many applications of digital watermarking, watermarked image of good quality is required. But there is a trade-off between a number of embedded watermark images and quality of watermarked image. This aspect is quite important in the case of multiple digital images watermarking. In this case, multiple images singular value decomposition based watermarking algorithm performs much better than other transform based methods. This paper presents robust multiple digital images watermarking using singular value decomposition (SVD) method. The results are compared with Discrete Cosine Transform (DCT) based multiple images watermarking method. In the case of multiple images DCT watermarking or in other transform based method more coefficients are varied according to the watermark images, which degrade the quality of watermarked image. In the case of SVD image watermarking method only singular values are being varied either in single or multiple images watermarking. This helps in preserving the quality of watermarked image.

Tarun Rathi, Rudra P. Maheshwari, Manoj Tripathy, Rahul Saraswat, X. Felix Joseph

The Role of Natural Ecosystem in Purifying Municipal Wastewater in Bahir Dar Metropolitan City

The main purpose of this study was to study the Ecosystem functionality in purifying municipal wastewater. Three drainage lines were selected to determine the efficiency of ecosystem in purifying waste water. The water quality parameters considered for this study were dissolved oxygen, total dissolved solids, biological oxygen demand, pH, conductivity, nitrate, phosphate, and ammonia. Pollutant load concentration flowing along to the three drainage lines and contributions to the Blue Nile river pollution were determined for the months March to May 2018. The load of BOD, TDS, and electrical conductivity, pH, nitrate, phosphate, and ammonia were reduced by 58.10%, 54.33%, 53.50%, 13.55%, 52.28%, and 75.20% respectively. The average concentration load of dissolved oxygen for canals #1 and #2 were enhanced by 70% while for Blue Nile river course it is reduced by 18%. Although the natural ecosystem show significant amount of reduction in chemical pollutants, the concentration in some parameters were still above the standard which requires enhancement of the ecosystem. Most water quality parameters of effluents at the Blue Nile river(Downstream) except BOD and DO were with within levels set by international standards for effluents to be discharged to surface water and FAO maximum permissible level set for waste water to be used for irrigation purposes. To reverse the adverse outcomes of effluents, treating wastes and preservation of the ecosystem is beneficial.

Fitfety Melese, Ayalew Wondie, Nigus Gabye

Analysis of Flexural Strength of Jute/Sisal Hybrid Polyester Composite

A flexural strength is one among the predominant factors for the polymer composites under perpendicular loading conditions against the axis of the member. In this study the flexural strength of Ethiopian Jute – Sisal hybrid polyester composite is investigated both analytically and experimentally. Composite test specimens have been prepared at various categories. They are based on different sequence of fibre layers: Jute-Sisal-Jute-Sisal (J/S/J/S), Sisal-Jute-Sisal-Jute (S/J/S/J) and Sisal-Jute-Jute-Sisal (S/J/J/S); fibres arrangement, based on orientation angle of fibres: [0°/45°/45°/0°], [0°/90°/90°/0°] and [45°/0°/0°/45°]; and based on concentration of fibers (weight ratio): [80% Polyester Matrix/20% Sisal/0% Jute], [81% Polyester Matrix/14% Sisal/5% Jute] and [76% Polyester Matrix/14% Sisal/10% Jute]. When comparing the results with different angle arrangement, [0°/45°/45°/0°] of fiber angled laminates is found to be most effective in flexural strength. And with different concentration of fibers in wt%, 10/14/76 [10% Jute, 14% Sisal and 76% Polyester Matrix] is found to be more satisfactory than the others in the flexural strength. From experimental result in sequence of fiber layers (S/J/S/J) has higher flexural strength than (J/S/J/S) and (S/J/J/S). From experimental result of jute/sisal polyester samples [0°/45°/45°/0°] has highest flexural strength which is 111.8 MPa and can resist maximum force of 469.5 N.

Yesheneh Jejaw Mamo, Ramesh Babu Subramanian

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