Advances of Science and Technology

The construction industry in Ethiopia is booming with a resulting increase in requirement of cement concrete as an input. The industry faced with depletion of natural aggregate, increasing the scarcity of landfills, haulage and landfill costs. The environmental and economic concern is not limited to concrete wastes but it also includes non-degradable wastes originating from materials like waste glass. In this study, recycled concrete aggregate (RCA) produced from a demolished concrete structure and waste glass powder (WGP) sourced from end-life and broken glass containers and bottles are used. A detailed experimental analysis is conducted to assess the workability and compressive strength of recycled aggregate concrete (RAC) made with partial replacement of natural aggregate (NA) and cement by recycled concrete aggregate (RCA) and waste glass powder (WGP) respectively. A concrete mix prepared with 0%, 25%, 50%, and 75% replacement of NA by RCA and 0%, 10% and 20% partial replacement of cement by WGP in each RAC mixes. The result shows that the waste glass powder replaced recycled aggregate concrete shows better workability and compressive strength development than the recycled aggregate concrete mix without waste glass powder and comparable with the control mix. The waste glass powder (WGP) as a partial replacement of cement can overcome the limitations of recycled concrete aggregate and paving the way for its broadly used in recycled aggregate concrete (RAC) production. The outcomes of this research would assist the growing construction industry to be sustainable thereby reducing waste and conserving the natural resource.

Concrete is the main construction material used for infrastructure construction around the globe. Since it is a brittle material, applied loads on concrete structures will result in sudden failure of the structure, and consequently the service of the structure will be affected. To prevent such failure, it is necessary to understand and predict the behavior and failure mechanics of concrete. Recently, the concept of the cohesive zone model has been widely applied to investigate various material failure phenomena. The potential-based model has advantages over the non-potential-based cohesive model in that their traction-separation relations are determined by taking the derivative of potential (cohesive interaction) concerning normal and tangential opening displacements. The purpose of this study is to evaluate the application of potential-based cohesive model for the study of concrete fracture by employing a user element in ABAQUS. The simulation is compared with reproduced experimental results and good agreement has been found between load-displacement curves.

Groundwater resources have a fundamental importance to satisfy the rapidly increasing agricultural, livestock and domesticwater requirements within the region especially in Robit watershed. Hence the quantification of this water resource is important for the efficient and sustainable water resource management. In this study spatial variability of irrigation water requirement, water use (abstractions) and groundwater recharge were estimated for Robit watershed within the eastern part of Lake Tana. Satellite image of Planet Scope on 2nd February 2017 was used to estimate area and type of crops cultivated in the watershed. CROPWAT model has been used to calculate the particular evapotranspiration and water requirement for irrigation using local climatic data. This was calculated for the dominant irrigated crops of Khat (Catha edulis Forsk), hop (Rhamnus prinoides), coffee, tomato and green pepper within the study area. Calibrated QSWAT model was applied to estimate net ground water recharges using local climatic data, soil map, crop management data and derived land use map from satellite image processing. The assessment showed that the entire amount of water applied for irrigation, domestic and livestock purposes was estimated as 1.35 Mm3/year, 0.02 Mm3/year and 0.03 Mm3/year respectively. Net groundwater recharge was estimated as 3.18 Mm3/year within the watershed. The estimation from the water abstraction survey showed that the total volume of water abstracted within the watershed was estimated as 1.40 Mm3/year. From the assessment it can be clearly seen that only 44% of ground water resource is extracted annually within the area and there is some potential to expand irrigation areas and the current water usage for various purposes in the future.

Currently, in developing countries, the construction industry which uses a huge amount of concrete is booming at a faster growth rate due to an ever-increasing population and urbanization. To satisfy the high concrete demand natural resources like natural sand are depleting and river beds are eroded due to mining of natural sand. On the other hand, construction and demolition wastes disturb the environment due to different construction and demolition activities. Thus, in this study RCFA from concrete cubes at a laboratory was used to check the suitability of RCFA for concrete production as a partial replacement of natural sand. A mix of C - 25 concrete was prepared with 0%, 10%, 20%, 30%, 40%, 50%, and 100% replacement of natural sand by RCFA with and without admixture to check the compressive strength and workability of concrete. The workability of mixes without admixture increases as the replacement ratio of RCFA increases and vice versa for mixes with an admixture. The compressive strength of concrete decreases as the replacement ratio of RCFA increases. Even if there is a decrease in compressive strength as replacement ratio of RCFA increases, it is possible to replace NS up to 20% without an admixture and up to 50% with an admixture for the production of C-25 concrete without a significant compressive strength loss from the control mix.

Estimating water supply through irrigation canal distribution systems is a crucial process for better water management in the irrigation schemes. This study aimed to develop an approach to predict the discharge delivered to unregulated irrigation canals (such as quaternary canals) from geometric and hydraulic information of regulated section of the system (such as tertiary and others) using machine learning approaches. The prediction performance of four Caret-based Supervised Machine Learning Models, namely; Multivariate Adaptive Regression Splines (MARS), Artificial Neural Networks (ANN), Random Forest (RF), and Radial Basis Support Vector Machines (SVM), were developed in the R programming environment, followed by variability assessment among canal outlets at Koga irrigation Scheme. Water delivery performance at quaternary canals showed a significant flow variation among the canal outlets. The comparative study of model prediction results showed identified MARS as the optimal model, both at the training stage (RMSE = 0.074 & R2 = 0.86 with normalized data) and testing stage (RMSE = 3.89 & R2 = 0.85 with rescaled data). Furthermore, the model building process and output equations of MARS were relatively interpretable compared to neuro and tree-based models, such as Artificial Neural Network and Random Forest. Thus, the MARS model was recommended to estimate the water supply to ungated irrigation canals as a function of flow rate information at gated distributary canal and other field data at lower components of irrigation schemes.

The efficient use and combination of the compressive strength of the concrete and the tensile strength of the structural steel create a high-quality solid composite material. However, the loose bond between the two materials has a huge negative effect by lowering the bending capacity unless connectors are introduced. Even if headed stud shear connectors are commonly used in the construction sector, the present study investigated the load-bearing capacity of partially encased composite beams through the replacement of the head studs with T shaped reinforcement shear connectors. Three-point loading with displacement control analysis had been performed numerically. The length of the flange, the height of the web and the location of the shear connections were considered key parameters. Among the parameters, the increased flange of the shear connector improved the tensile behavior of the concrete through the formation of adhesion. On the other hand, the intermediate web height showed a positive result to confine the concrete with the equivalent bond formation with the structural steel. For general composite beams, slip and concrete cracking increase away from the neutral axis which reduces the load-bearing capacity of the composite beams. Hence, lowering the shear connector’s location to the bottom flange reduced the slip. As a result, the capacity of the composite beam was improved by creating an efficient anchorage with the shear connector, which increased the stiffness of the composite beam.

In the recent time Ribb River is under immense morphological change due to various natural, planned and unplanned anthropogenic activities such as, lake level regulation for hydropower production, embanking, sand mining, and water extraction. In the present time, Lake Tana level is raised (kept fairly constant) after the Chara-Chara weir construction and Belese Hydropower operation. These will strongly alter both River regime water and sediment discharge to downstream reach and causing morphology adjustment. Hence, this study assessed Lake level fluctuation impact on River morphological change on Ribb River, Lake Tana Basin, Ethiopia for about 20 km. The objectives of this study were to assess lake level impact on river cross-sections of Ribb River and investigate back water extension length and its consequent for River training structures. Primary data (River cross-sections, dyke dimensions and grain sizes) were collected through, surveying using standard measuring equipment’s (total station, GPS) and laboratory analysis. Secondary data (stream flow, Lake level, sediment, rainfall and climatic) were also collected from MoWRIE. For data preparation and analysis, Arc GIS and HEC-RAS were used. River bed change has been studied from 2005 to 2014 period and the result show that the reach exhibit both aggradation and degradation. The study reach is affected by back water for about 1.5 km length and this back water effect caused an average annual rate of 0.22 m deposition.

Water quality is used to demonstrate chemical, physical and biological characteristic of water. It has a significant impact on human’s day to day activity. Even if it has such prominence, its quality is not constant with time and known as a media for disease transmission in the globe. In Ethiopia, there is a shortage of information in seasonal variation of water quality characteristics of drinking water sources. Thus, a cross-sectional study was undertaken to analyze water quality characteristics of drinking water sources in Finote Selam. A total of 32 water samples were collected from four drinking water sources and used to analyze turbidity, EC, TDS, NO3, TC, FC, Ca, Mg, PO4, PH, Fe, NH3 and temperature. From a total of 16 water samples tested for water quality parameters in each season, some of the parameters were above the WHO standard in the dry and wet season. For turbidity 2 (12.5%), EC 16 (100%), TC 16 (100%), PO4 3 (18.75%) and FC 12 (75%) were above WHO standard in the dry season whereas for turbidity 11 (68.75%), EC 14 (87.5%), TC 16 (100%), PO4 6 (37.5%), Mg 2 (12.5%) and FC 16 (100%) were above WHO standard in the wet season. For PH 11 (68.75%) and 12 (75%) water samples were below WHO standard in the dry and wet season respectively. The research result indicated that the quality of water sources were not safe in dry and wet season since majority of the samples taken were not meet WHO standard. So, it is desirable to monitor and manage drinking water sources.

In the recent decade, the change in land use and land cover have changed the ecosystem services more rapidly than the previous similar periods. Land use land cover (LULC) change is the major factor that affect the watershed response. The main objective of this study was to assess the impact of land use and land cover change on the response of the Borkena watershed. The LULC change analysis was evaluated using supervised classification in ENVI software. The SWAT model was used to assess the impact of LULC change on streamflow for the period from 1996 to 2016. The study result revealed that the Borkena watershed experienced significant LULC changes from 1986 to 2016. Most of the grass land, cultivated land, and shrub land were changed to build-up and bare Land. The LULC map showed an increase of buildup area and bare land by 3.6% and 5.9%, respectively. There was a good agreement between simulated flow and observed data with a coefficient of determination (R2) and Nash-Sutcliff Efficiency (NSE) values of 0.81 and 0.79 in calibration, and 0.75 and 0.74 in validation periods, respectively. The evaluation of the SWAT hydrologic response due to the change in LULC showed that monthly streamflow was increased by 5.4 m3/s in the wet season and decreased by 0.5 m3/s in the dry season, and there was a significant effect (p < 0.05) of LULC change on watershed response. The changes in land use have resulted in changes in streamflow, due to the expansion of urbanization and land degradation.

Enhancing performance of irrigation schemes requires an improvement in the timing and amount of irrigation application from head to tail of irrigation infrastructures. This can be achieved using non-invasive techniques using thermal imaging to assess soil moisture regimes and plant water status. An infrared thermometry with hand held thermal camera attached to a tablet was used to measure the temperature of wheat canopy under three irrigation treatments in Koga irrigation scheme: wetting front detector (WFD), chameleon and control reflecting farmers’ practices. The experiment followed a randomized complete block design (RCBD) in two irrigation blocks (Adibera and Chihona) with three treatments and three replications. The temperature of the canopy was measured before and after irrigation. The calculated Crop Water Stress Index (CWSI) using canopy temperature was significantly different in the WFD treatment during the development stage given the larger irrigation intervals observed (p > 0.05). Overall, both irrigation technologies show potential in improving water management close to the overall estimated gross irrigation requirement with some further improvement in the mid development stage. The study showed the potential of using thermal imaging to not only identify CWSI and assess the effect of agronomic field trials using in-situ thermal camera’s but also the potential of using canopy temperatures in estimating actual ET and therefore gross irrigation requirements. This would provide a new opportunity for agricultural extension agents to advice smallholder farmers in irrigation schemes and beyond on when and how much to apply without the need for WFD or chameleon sensors. Further research is needed to calibrate and validate the irrigation predictions based on different soil and crop types.

Concrete has a very low fracture energy and due to this, it cracks at very low load in brittle mode. The main objective of this study was to determine the effect of the addition of glass fiber on the fracture energy of plain concrete of grade C20/25 and C25/30. The percentage of glass fiber added ranges from 0% to 0.6% by volume with a constant increasing interval of 0.2%. The glass fiber are placed in three layers with equal amount placed at uniform interval. The test is performed according to RILEM TC 50 FMC recommendation following the Work of Fracture Method (WFM). It has been observed that addition of glass fiber increases the fracture energy of plain concrete very significantly and change the failure mode from brittle to ductile.

Floods are considered as harmful and the most dangerous natural disaster affecting annually millions of people. This study aimed to present a geospatial information system based multi-criteria evaluation techniques (MCE) methodology for flood hazard areas mapping. The distance from drainage network, slope, recurrent heavy rainfall, curve number, normalized difference vegetation index (NDVI), and the population density are the six factors considered as relevant to the flood hazard areas mapping of the basin. The final flood hazard areas map of the basin shows a satisfactory agreement between the spatial distribution of historical floods that happened in the basin for the past years and the flood hazard zones. The flood hazard map showed that Bilate-Humbo area at the very entry of Bilate River to Lake Abaya, Shashego area at Boyo Lake resulting from Guder River, and Shashego area at Boyo Lake resulting from Metenchiso River are the areas of very high flood hazard. These areas are categorized by low NDVI, gentle slope, high rainfall, high curve number and close to the drainage network. The proposed methodology of assessing flood hazard areas using spatial information system delivers a good basis for developing a system of flood risk management in a river basin.

Steel fiber improves the strength, ductility (post-peak ductility), and energy absorption capacity of concrete. Despite of its numerous advantages, application of steel fiber in structural members like beam, column and elevated slabs is still in its early stage. In a structural member where complexity of loading is prevailed due to many reasons, torsional or twisting load avail itself either with other loads like shear and flexure or dominantly by itself called pure torsion. Failure of torsion of concrete on the post cracking stage can be predicted by the skew bending or space truss analogy and it is reliant on the tensile strength of the concrete and its ductility which in turn concrete is lack of. Therefore, with the advancement of technology addition of fiber (i.e. that is well known by its crack arresting behavior) in concrete gives an advantage on concretes inability. The improvement degree of steel fiber in concrete is also affected by concrete strength, fiber type, volumetric ratio, and fiber aspect ratio. Thus, this paper provides a summary of the properties of steel fiber reinforced concrete subjected to a twisting loading and gives a recommendation on areas that yet need further investigation.

There is a need to identify alternative fuels suitable for running diesel engine as a replacement of diesel to address the problems like depletion of fossil fuel reserves and environmental pollution. The fuels derived from bio-resources found to be good alternatives for conventional petro-fuels in solving such issues. The impact of cotton seed oil biodiesel blend on vehicle performance with four stroke four cylinder diesel engine was investigated. Emission test was performed on six cylinder engine vehicle using 100% diesel of petroleum origin (fossil diesel), and B10, B20, B30 of cottonseed oil methyl ester. Analysis was carried out on major performance parameters Pb, Tb, bsfc & emissions such as NOx, CO, CO2, O2 and HC. It is observed that Blends of biodiesel B10, B20 & B30 reduced brake torque by 5%, 7% & 12%, also reduced brake power by 6%, 8% & 11% and increased in fuel consumption by 4%, 8% & 20% respectively. However, the emissions of the CI engine running on three biodiesel blends were reduced, CO by up to 16%, CO2 by 17% and HC by 12% & increase NOx by 14% & O2 by 18% as compared to diesel fuel. It is concluded that blend of 20% cotton seed biodiesel can be used in an unmodified diesel engine.

Composite materials are group of engineering materials which are combinations of more than one material type with the intention of getting specific material properties. The components of the composite may be metals, ceramics, plastic or other materials. The manufacturing methods of composite materials especially fiber reinforced plastics requires combining two or more materials in defined orientation. Among the different fiber reinforced plastic composites manufacturing methods hand layup method comprises 22% and exclusively implemented in developing countries. Other advanced manufacturing methods such as resin transfer molding, compression molding and auto calve require high capital and technical expertise. It is possible to say all the manufacturing methods have their own limitations. Resin spray over a laid up fiber stack is first phase of a new manufacturing setup which will be followed by pressure compaction. In this paper the spray process is modeled using computational fluid dynamics in 3D spray region of size 30 × 30 × 60. In the modeling spray characteristics of the fairly viscous unsaturated polyester resin using different nozzle types have been analyzed. The result shows only few types of nozzles are capable of spraying the 0.3 kg/m-s viscosity liquid with fairly good area and distance of coverage. In the case of pressure swirls atomizer about 30 cm distance from the atomizer results a fairly uniform distribution.

This study aims to supply sufficient drinking water for hot land regions in Ethiopia, specifically higher institutions such as ASTU, Dilla, Semera, Derie dawa, Gambiela and Assosa Universities. The investigation focuses on evaluating the performance of locally manufactured public water coolers developed using the VCRS system.The predestined parameters are inlet temperature of water (44 ℃), the estimated time, the volume of water, surrounding temperature of the air (28 ℃), and heating load of evaporates (12847.87 kJ). Two models are designed in the present investigation, the first one for experimental and the second for numerical analysis and for compare with experimental analysis and previse investigation. After design and select the component the model developed and simulated using EXCEL. R134a is selected as a refrigerant because it has less global warming potential, zero ozone depletion potential value, inexpensive and easily available. Aluminum sheet, R134a, spray foam, thermostat, and VCRs components are materials used to fabricate the coolers. The walls of the storage tank is wounded by the evaporator coil. Due to high performance of cooler, the storage type of water cooler is selected. The theoretical results have been validated with experimental results and the present study compares with the literature. As per this investigation, the cop of the cooler is recorded 3.17 and 3.89 for experimental and theoretical results respectively. This result variation is detected due to ideal assumption of VCRs process.

Plastics have become the most popular and ubiquitous material in our daily lives and global plastic production has increased significantly. A large portion of the plastic is used to produce disposable packaging items, which are discarded and accumulated as post-consumer wastes both on the land and oceans. Distributive recycling of waste plastics through additive manufacturing became the most effective solution to overcome environmental pollution and reduce the use of fossil oils and gases. With the rise of additive manufacturing, the demand for polymers has increased exponentially and many scholars are concerned about how 3D printing filaments should be reproduced from recycled plastics. This review aimed to study the potentials of using recycled plastic for 3D printing filament to minimize environmental pollution and preserve material sustainability. The study revealed promising results for the use of recycled post-consumer plastic as a more sustainable and environmentally friendly 3D printing filament material. The impact of plastic degradation on their mechanical and thermal properties due to subsequent extrusion and contamination of plastics by impurities was also studied. Besides, the additive materials used to enhance mechanical properties and increase the molecular weight of recycled material are discussed. Finally, a conclusion is drawn and future research opportunities are also addressed.

Sustainable performance demands to show a sustained competitive advantage that lasts a long period. “Industrial Parks” is now the gateway to sustainable development, especially in the least developing countries like Ethiopia, for example. The industrial parks are highly attracting foreign direct investment and working for the inclusive development of the country. Though this is a good start, the capability is at an initial stage and needs support in terms of their performance towards creating a sustainable operation. Based on the evidence of both theoretical and empirical literature findings, this study paper conducted a review and identified the sustainability measures and practices from which it tries to filter the key capability measures and practices for the Ethiopian industrial parks. For integrating the identified practices and measures, as a methodological approach, the theory of dynamic capability process is considered, encompassing sensing, learning, and transforming the cyclic loop. Practices and measures are incorporated in each process of dynamic capability pillars. A conceptual model was developed as the final output showing the holistic map of the integrated sustainability measures and practices. The measures and practices identified will fully support the sustainable growth and decision process of the industrial park operation. It also adds value to the body of knowledge in industrial sustainability in special economic zones.

This paper aims at developing a model for the planned maintenance program and long-run average cost. Markov process decision approach in its discrete version used to model the problem. Penalty cost model due to shifting paradigm as approach applied for textile boiler maintenance program by taking three components of the boiler. Whereas, a three-step policy iteration algorithm, initialization, value determination and policy improvement, for numerical experimentation based on component current age and the schedule maintenance time for the planned maintenance program considered. Relative values (RV), which are not only immediate value from an action taken from planned activity but also are guaranteed values that would be resulted from the accomplishment of the maintenance action specified on the maintenance policy proposed. More importantly, unless a trade-off is made, RVs instead are costs in the long run and this is what the average cost-policy compromise and the policy iteration assures while, as time gets advance the deterioration rate of the components expected to increase, shifting forward will bear an extra cost is the underlying. With this proposed approach, for validation purpose, relative values (RV), based on the two shifting strategies, Forward (FW) and Backward (BW) shifting compared with that of on-schedule (OSC) maintenance, stationary policy based on the long-run average cost obtained to be 2053Birr for the specified case.

Traditional paddy threshing is still carried out by man-power, and animal trampling in the rural village of Fogera district in the Amhara region of north-west Ethiopia. This paper was aimed to reduce paddy losses, minimize drudgery activities, and avail the technology in this area. The developed rice thresher also protects the paddy from mud mixing for further prevention of fast wearing and damaging of rubber roll during rice milling. The 3D modeling and working drawing are prepared by using CATIA software for fabrication and testing purposes. The paddy thresher is designed to separate paddy from panicles without damaging the stalk of rice. The research seeks to develop a power-operated rice thresher that can be manufactured by local manufacturers, and accessed by all small-holder rice producing farmers in Ethiopia. Components of the thresher were designed, fabricated, and assembled from the available materials in the local market. The experimental test in this study indicated that the threshing capacity of the designed paddy thresher is approximately 128 kg/h using two labor participation. Considering the unthreshed loss, drum loss, and broken grains, the average efficiency of the machine noted 96.6%.

This review paper focuses on the metal injection molding process and undesirable defects that occur during part manufacturing. In this paper, common types of metals for injection molding, process parameters, and MIM applications are deeply reviewed from recent research works. MIM process merges the high capability of plastic injection molding technology to produce intricate molds with the advantages of a powder route to process metallic, ceramic, or composites materials. The drawbacks of the MIM process come from diverse technical steps involved in the production of the part (feedstock production, injection, debinding, and sintering). The product quality of MIM is depending on feedstock preparation, mold design, process parameters like temperature and pressure, debinding technique, sintering process, etc. However, the advancement of MIM has proven that can produce very small size and large volume production with low cost when we compare to another manufacturing process. Generally, this study has been presented MIM process parameters, existed defects in MIM and possible remedial solutions, and also future research scope.

It is true that advancement in engineering and technology directly depends on the advancement of modified or new engineering materials. Now a day’s Composite materials are receiving remarkable attention by enhancing the desirable properties of monolithic materials. Some product design requires a material that has a combination of two or more desirable properties in one, such as strength, hardness, wear-resistant, corrosion-resistant, good thermal and electrical conductivity, castability, machinability, etc. Metal matrix composites can satisfy the functional requirements of a specific product by varying the weight ratio of the selected metal matrix, and reinforced particles. Currently, aluminum matrix composite has a wide application in the production of enhanced automotive, aerospace, medical, and other machinery spare parts. This review paper mainly focused on the aluminum metal matrix composite which contains silicon carbide particles as reinforcement. In this review paper, different properties like mechanical, chemical, and physical properties (thermal and electrical conductivity) of the aluminum matrix composite are discussed, besides various types of manufacturing techniques, process parameters, applications, and future research gaps were studied in detail. This review paper specifically studies the effect of silicon carbide particles (SiCp) reinforcement in the aluminum metal matrix and their related phenomenon.

The objective of this work is to investigate the ballistic affect energy absorption behavior manufactured from Kevlar and jute-epoxy fiber sandwich composite materials by using finite element analysis and simulation techniques for impact protective helmet applications. Energy consumed and bullet speeds for these composites are examined analytically and using finite element analysis (FEA). Finite element analysis of Kevlar (KM2) plates is carried out at distinctive thicknesses (12 mm, 14 mm, and 24 mm). The analytical results of KM2 and KM2 with JE sandwich plates agree well with the results obtained from FE analysis with a maximum error of 1.14 m/s. The study on the KM2 composite plate uncovers that thickness has a noteworthy impact on the energy absorption properties. The energy absorption of the KM2 sandwich is 78.167% greater than the KM2 plates.

The main objective of this study is to investigate the effects of the fiber surface treatment on the mechanical properties of bamboo fiber reinforced polyester resin composite materials for different applications. To investigate the mechanical properties of the materials different chemical treatments and experimental testing setups have been used. Four different types of testing samples were prepared from bamboo fiber reinforced polyester resin composites using untreated bamboo fiber, 10 Vol% NaOH treated bamboo fiber (10TBF), 20 Vol% NaOH treated bamboo fiber (20TBF), and 10 Vol% NaOH plus corn starch soaked for 30 min treated bamboo fiber. To characterize the mechanical properties of the fabricated composite materials, the WAW 1000D hydraulic universal tensile testing machine with ASTM ISO-6892 standard, ABAQUS CAE finite element analysis, and GOM Correlate Software integrated digital image correlation (DIC) analysis were used. The results obtained indicate that the use of higher volume percentage of NaOH treatment chemical leads to uniform distribution of stress fields on the surface of materials. In addition to that, the use of 10 Vol% NaOH plus corn starch soaking of bamboo fiber gives improved elastic and elongation properties.

The Halohydrine dehalogenase (HheC), active site is buried deep inside the structure of the enzyme and to enter the active site, the substrate must cross via the body of the enzyme called tunnels. In several studies revealed that they have been influenced substrate selectivity, stability and activity of enzymes. Know a day, identifying and understanding how tunnels exert selectivity, stability, and activity regulation of enzymes have been growing interest in the fields of computational approach and enzyme engineering. As far as, the HheC concerned studies suggest that the release of chloride ion determines the overall activity of the enzyme and thus tunnels are assumed to exist. Swiss-Modell, Auto dock 3.2, Gromacs 5.2.1, Caver 3.0, and RAMD computational techniques were applied to identify and analyze tunnels and how chloride ions migrate through these tunnels. The purpose of this study is to identify tunnels and analyzes how to influence Chloride ion-releasing activity in the HheC enzyme and provide prerequisite data for wet-lab experiment used to improve overall activity. In this study, we found the presence of Chloride ion narrowed tunnels compare to free HheC enzyme. Moreover, conformation difference, tunnel lining residues and bottle-neck residues were identified for next wet-lab experiment. Future wet-lab investigations to validate the role of residues that are found in tunnel lining could be needed to engineer the activity of HheC.

Europium doped gehlenite phosphor glassy powders were successfully prepared by spray pyrolysis followed by annealing under air, N2 and N2/H2 treated gases. In this paper, it is of great attention and importance to find that the reductions of Eu3+ to Eu2+ ions can be realized. To identify the oxidations of europium ions, the X ray photo spectroscopy (XPS) was used. The photoluminescence (PL) properties intensively studied under different excitation in which the result shows that the europium doped phosphor gehlenite glassy powders emit a strong red light in air and N2 treated gases; while under N2/H2 treated gas, blue light was observed.

The Solar chimney power plant is a naturally driven power generating system. In this research, a solar chimney power plant is studied by developing an experimental model for a maximum power output of $$32\,\mathrm{W}$$ 32 W . The performance of large-scale electricity generation from the plant is predicted by analyzing different geometrical configurations. CFD model is used to study flow characteristics of air temperature inside the collector. Then, for 30 kW power output, the selected optimized dimensions are: chimney height, collector diameter, chimney diameter, and collector height are estimated to be 15 m, 15 m, 0.2 m, and 0.2 m respectively. For a fixed chimney diameter and collector height, an increase in height of the chimney raises the power output until it reaches the designed optimum height, an increase in chimney height beyond the optimum value will result in an energy loss due to lower total pressure difference caused by frictional pressure rise. The experimental model developed is scaled down to a chimney height of $$3\,\mathrm{ m}$$ 3 m and collector diameter of $$2\,\mathrm{m}$$ 2 m with a maximum power output of 32 W. In the experiment, the characteristics of the temperature inside the collector are studied by varying the height of the collector above the ground. The temperature difference between collector exit and collector inlet from the comparison of experimental and simulated modeled are in good agreement. It was found that the implementation of a solar chimney power plant is technically feasible for the generation of electrical energy up to the desired potential by adjusting chimney height and collector diameter.

In the present study the performance of an institutional mirt stove with waste heat recovery system was designed and investigated. The waste heat recovery system is designed to utilize the heat of waste gases of institutional mirt stove as a source of energy for the purpose of injera baking on the secondary mitad. Beside to this main design improvement, adding fuel supporting structure like grates to allow ash falls through it and air to be entered under-neath the fuel and ash collection boxes and ash removal openings below each grate were provided. The performance of the improved stove was compared with that of the existing institutional mirt stove through controlled cooking test method. The result shows that the improved stove saved up to 16% fuel wood and 14% cooking time as compared to the existing institutional mirt stove. During the test a temperature of about 216.3 ℃ on the surface of a secondary mitad is achieved and injera is baked on this surface. Finally, the techno-economic analysis shows that the improved institutional mirt stove with waste heat recovery for injera baking system is economically feasible.

This work provides the experimental test results and findings of solar cooker developed in Bahirdar. The cooker is double exposure type consisting of plane reflectors being fixed on top glazing and an asymmetric compound parabolic concentrator fixed on the side wall. It has a box casing with an aspect ratio of 2.66 and overall dimension of $$920\, {\text{mm}} \times 343\,{\text{mm}} \times 400\,{\text{mm}}$$ 920 mm × 343 mm × 400 mm . Stagnation tests were conducted on the double exposure and conventional solar box cooker. From the test maximum absorber plate temperature of 145 ℃ for the double exposure and 122 ℃ for the conventional cooker have been achieved at 12: 30 PM and 12:40 PM respectively. The respective first figure of merit values were found to be 0.123 and 0.088, the former satisfying minimum requirement as per BIS. Water or load test conducted indicates as it has taken 2 h and 30 min for 2 L of water to boil in the double exposure solar cooker while in conventional cooker water doesn’t reach its boiling point, being heated to a maximum temperature of 88 ℃. For the food cooking, 1 kg of rice distributed in two pots was cooked in 1 h and 35 min, starting from 10:00 AM. 1 kg of bean was cooked in 2 h and 45 min. The double exposure cooker is therefore able to cook hard meals like bean and soft meals like rice and spaghetti two and four times per day respectively. This food cooking result has good implication that if intensive work is done, solar cookers can be disseminated into and used by the society.

In Ethiopia injera is consumed by most of the population. However, the application of solar dryers in drying injera is not a common practice. The aim of this study is to evaluate the performance of a modified mixed mode solar injera dryer which integrates a vertical air distribution channel using energy and exergy analysis and to determine the economic significance. The overall drying efficiency of the modified dryer in drying injera was found to be 10% and it takes around 4 h to reduce the moisture content to 0.14 g water/g solids. In drying injera, an even temperature distribution of drying air was observed over the drying trays with 2 ℃ temperature difference. The embodied energy of the modified dryer was obtained to be 765.46 kWh. The overall exergy efficiency of the modified dryer was found to be 13.2% and the result indicated that the exergy efficiency has an inverse relation with exergy loss. The exergy losses of the bottom and top trays were found to have very similar values and the exergy losses were observed to have monotonic relation with exergy inflow and an inverse relation with moisture content. From the economic analysis the saving per day of the modified dryer turns out to be 111.48 ETB/day and the cumulative present worth of the annual savings by using the modified dryer was found as 154,459 ETB with payback period of 104 drying days. This solar injera dryer will be a cost-effective choice for mass producers of dried injera.

Ethiopia is a developing country, where population living in the country side still does not have access to electricity – for the most part. The majority of the population in the rural areas uses fossil fuels for house hold use. Fossil fuels are friendly to the environment. Renewable energy sources are alternative solutions to mitigate these problems. Ethiopia is endowed with numerous renewable energy resources naturally. The major ones are small-scale hydropower, biomass, and solar power. This paper deals with the design and implementation of a hybrid power generation energy management system to be used in the Benti rural village of Fogera Wereda. Managing the different energy sources is discussed in detail. The Fogera site consists of 426 households with a total electric power demand of 120 kW. To satisfy this demand, 50%, 30%, and 20% are to be contributed from hydro, solar, and Biomass power system generations respectively. A fuzzy logic controller is used as the main component of the power management system. The controller monitors the demand coming from the loads and which sources are available to switch to the appropriate power supply regularly.

Areke is a traditionally fermented and distilled beverage. And it is one of the frequently consumed drinks in semi-urban and rural areas of Ethiopia. Also, it is a drink for most people in the country. Regarding its preparation, it is brewed using a three-stone fire which consumes a large amount of firewood and generates significant indoor air pollution. The evaluation and comparison of thermal and emissions performance of existing cook stoves employed for Areke distillation may help the rural poor and semi-urban population to reduce the economic and health costs associated with its preparation. In doing so, Control Cooking Test (CCT) protocol was employed for all the three types of stoves: a three-stone fire, traditional Areke stove, and Mirt Areke stove. The test results showed that Mirt Areke stove reduced fuel use by 51% compared to the three-stone fire while the improvement made by the traditional Areke stove is 36%. Indoor air pollution indicators of CO, PM2.5 and PM10 also showed a reduction by 29%, 53%, and 52%, respectively, while comparing Mirt Areke stove with three-stone fire. In the case of a traditional Areke stove, the percentage increase in CO is 14.3% while percentage reduction in PM2.5, and PM10, is 17.9% and 18.3%, respectively. These results indicate that the improved Mirt Areke stove has a better performance than the traditional Areke stove.

Escalation of small‐scale irrigation is supposed to be an essential requirement for the growth of the agricultural sector in developing countries. In Ethiopia intensification of small-scale irrigation has got a policy priority for rural poverty mitigation, growth, and building climate adaptation economy. The irrigated land in Ethiopia is not far from 5% of irrigable land, and only around 5% of available water resources are utilized annually. To maximize the effort deploying an environmentally friendly and less expensive technological alternative needs attention. In this regard, pressurized irrigation schemes that operate on renewable energies such as hydro-powered pumping contribute more. Even though the technology has an obvious advantage over the other pumping technologies, they are not been used gradually through time and are mostly ignored. The objective of this study was to conduct strengths, weaknesses, opportunities, and threats analysis on prospects of a hydro-powered pumping system for small-scale irrigation in Ethiopia. In this regard, important small-scale irrigation pump problems were examined and prospects and barriers of hydro-powered small-scale irrigation pumping systems were identified. A comparative study was conducted for comparative between existing pump types (Engine powered, Motor powered, and Manual) deployed in the community for small-scale irrigation. According to the study result, the hydro-powered pumps have better prospects for small-scale irrigation.

We presented the performance of H-type vertical axis hydrokinetic turbine (VAHKTs). To study the hydrodynamics of VAHKTs an analytical method using a double multi-stream tube (DMST) model was used and an experimental study was employed to validate the DMST results. The key difficulty in the development of VAHKTs technologies is the limited number of researches that show the actual performance under different water velocities. We developed a Matlab code to predict the performance and for validation experimental investigations were performed. The performance operational parameters of power coefficient $$(C_P)$$ ( C P ) and torque coefficient $$(C_Q)$$ ( C Q ) were used with tips speed ratio (TSR). To validate the DMST and experimental results we used a reference turbine (RM2) developed by the USA Department of Energy’s (DOE). A good agreement was found between the analytical and experimental results with the reference turbine. From the study, it is found that the $$C_P$$ C P of VAHKTs show an increment and then decrease as the TSR increased. The operating region for VAHKTs is between $$1.2\le TSR\le 3.8$$ 1.2 ≤ T S R ≤ 3.8 . The study illustrated that at $$TSR \ge 4$$ T S R ≥ 4 it is found that there is no power generation from VAHKTs. As s result, the Matlab code we developed based on DMST can be used as a cost effect and robust tool to design and predict the performance of VAHKTs.

In this study, a comparison of two artificial intelligence inspired solution methods employed to solve Security Constrained Economic Dispatch (SCED) of Ethiopian Renewable Energy Systems (ERES) is presented. The solution methods are Efficient & Parallel Genetic Algorithm (EPGA) and Hopfield Neural Network (HNN). This paper argues that employing intelligent SCED that considers power mismatch and intermittency of renewables can solve ERES’s recursive blackouts. A simulation was conducted on MATLAB. According to the results, both solution methods provide the best solutions for their respective purposes. For providing accurate forecast & predictive control of intermittent generation, it is imperative to employ HNN. When obtaining global maxima of multi-objective function is required, it is recommended to employ EPGA. Generally, employing intelligent SCED is a key planning step in adopting smarter grids as it reduces the production cost and the number of blackouts while increasing the security level of ERES.

Copper doped MnO2 nanoparticles have been developed by co-perception technique without using any surfactants and templates. The physiochemical and thermal properties of the as-prepared nanoparticles have been analysed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Thermogravimetric analysis (TGA) and/or Differential thermal analysis (DTA). The catalytic performance of MnO2 and Cu doped MnO2 nanoparticles have been assessed via cyclic voltammetry (CV). The crystal structure of MnO2 and Cu doped MnO2 nanoparticles was the sharply crystallized α-MnO2. However, the Copper dopant has no noticeable influence on the crystallization of MnO2 as determined by the results of XRD analysis. The formation of M-O (M = Mn, Cu) was confirmed from FTIR study. Cu-doped MnO2 nanoparticles showed improved thermal stability as confirmed by TGA/DTA analysis. The doping amount had a high impact on the catalytic performance of the Cu-MnO2 nanoparticles. The Cu-MnO2 nanoparticles showed better catalytic performance as compared to pure MnO2. Hence, Cu-doped MnO2 nanoparticles showed improved catalytic activity and thermal stability.

Perovskite solar cells are one of the most promising solar cell technologies, showing rapid development in power conversion efficiency (PCE). In this work, the performance and stability of triple-cation perovskite solar cells under continuous outdoor illumination in Bahir Dar climatic conditions and also the luminescence properties using steady-state photoluminescence (PL) spectroscopy has been studied. The work is conducted to study the electrical characterisation of the device under investigation in outdoor testing under ambient conditions to study the open-circuit voltage, short-circuit current density, fill factor, and efficiency of the device and obtained a PCE of above 16%, and a fill factor of above 60% with strong PL peak emission at 757 nm.

In this paper, we aim to develop low cost effective model for evaluating the aerodynamic design and performance of small scale straight blade H-Darrieus vertical axis wind turbine (VAWT). To optimize the rotor design the blades are modeled with variable pitch angle (β) configurations. To this end, DMST model was used to determine optimum pitch configuration at the minimum possible tip speed ratio (λ). Once the optimal design point was obtained, 2D unsteady computational fluid dynamics (CFD) simulation was carried out in order to describe the flow physics of the rotor. The power coefficient (Cp) obtained in DMST model was 0.464 which is in agreement with the present CFD simulation result computed by SST k-ω model (i.e. Cp = 0.4537) and wind tunnel experimental findings from literatures. This implies the performance of straight blade H-Darrieus VAWT with VP design is 37.2% better than one with the fixed pitch (β = 0°) blades. Hence, the present study delineates the performance of H-Darrieus wind turbine is dependent upon the turbine parameters, airfoil profile and desired blade pitch angle for sustainable power generation.