Search results for: Gashaw Abebaw
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 12

Search results for: Gashaw Abebaw

12 The Effect of Partially Replacing Cement with Metakaolin on the Properties of Concrete

Authors: Gashaw Abebaw

Abstract:

Concrete usage in Ethiopia is expanding at a faster rate than before. Cement is the most important and costly ingredient in this respect. The construction industry is currently challenged by cement scarcity and stock market inflation. Scholars' trays, on the other hand, will use natural pozzolan material to substitute cement. Apart from that, Metakaolin has pozzolanic characteristics. According to the industrial mineral occurrence map, Ethiopia kaolin may be found in abundance. Some of them include Debretabor, so it is good to utilize Metakaolin as cement replacement material. In this study, the capability of Ethiopian Metakaolin as a partial substitute for cement in C-25 concrete production with 0%, 5%, 10%, 15%, and 20% replacement of PPC by MA with 0.49 percent water to cement ratio is investigated. The study examines; the chemical properties of MA, Physical properties of cement paste, workability, compressive strength, water absorption, density and sulfate attack of concrete was investigated. The chemical composition of Metakaolin was examined and the summation of SiO₂, AlO₃, and FeO₃ is 86.25% and the ash was classified class N pozzolan. The normal consistency percent of water increases as the MA replacement amount increase and both initial and final setting time rang increase as the MA replacement amount increase. On the 28th day, the compressive strength of concrete with MA replacement of 5%, 10%, and 15% exceeds the goal mean strength (33.5Mpa) with compressive strength enhancements of 2.23 %, 4.05 %, and 2.23 %, respectively. Similarly, on the 56th day, 5 %, 10%, and 15% replacement enhance concrete strength by 2.06 %, 3.06 %, and 1.2 %, respectively. The MA mixed concrete has improved significantly in terms of water absorption and sulphate attack, with a 15% replacement level. MA content Metakaolin could possibly replace cement up to 15%, according to the studies. The study's findings will help to offset cement price increases while also boosting house affordability without significantly degrading.

Keywords: metakaolin, compressive strength, sulphate attack, water absorption, N pozzolan

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11 Phytoremediation of Cr from Tannery Effluent by Vetiver Grass

Authors: Mingizem Gashaw Seid

Abstract:

Phytoremediation of chromium metal by vetiver grass was investigated in hydroponic system. The removal efficiency for organic load, nutrient and chromium were evaluated as a function of concentration of waste effluent (40 and 50% dilution with distilled water). Under this conditions 64.49-94.06 % of chromium was removed. This shows vetiver grass has potential for accumulation of chromium metal from tannery waste water stream.

Keywords: chromium, phytoremediation, tannery effluent, vetiver grass

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10 Prevalence and Associated Factors of Attention Deficit Hyperactivity Disorder among Children Age 6 to 17 Years Old Living in Girja District, Oromia Regional State, Rural Ethiopia: Community Based Cross-Sectional Study

Authors: Hirbaye Mokona, Abebaw Gebeyehu, Aemro Zerihun

Abstract:

Introduction: Attention deficit hyperactivity disorder is serious public health problem affecting millions of children throughout the world. Method: A cross-sectional study conducted from May to June 2015 among children age 6 to 17 years living in rural area of Girja district. Multi-stage cluster sampling technique was used to select 1302 study participants. Disruptive Behavior Disorder rating scale was used to collect the data. Data were coded, entered and cleaned by Epi-Data version 3.1 and analyzed by SPSS version 20. Logistic regression analysis was used and Variables that have P-values less than 0.05 on multivariable logistic regression was considered as statistically significant. Results: Prevalence of Attention deficit hyperactivity disorder (ADHD) among children age 6 to 17 years was 7.3%. Being male [AOR=1.81, 95%CI: (1.13, 2.91)]; living with single parent [AOR=5.0, 95%CI: (2.35, 10.65)]; child birth order/rank [AOR=2.35, 95%CI: (1.30, 4.25)]; low family socio-economic status [AOR= 2.43, 95%CI: (1.29, 4.59)]; maternal alcohol/khat use during pregnancy [AOR=3.14, 95%CI: (1.37, 7.37)] and complication at delivery [AOR=3.56, 95%CI: (1.19, 10.64)] were more likely to develop Attention deficit hyperactivity disorder. Conclusion: In this study, the prevalence of Attention deficit hyperactivity disorder was similar with worldwide prevalence. Prevention and early management of its modifiable risk factors should be carryout alongside increasing community awareness.

Keywords: attention deficit hyperactivity disorder, ADHD, associated factors, children, prevalence

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9 Commercialization of Smallholder Rice Producers and Its Determinants in Ethiopia

Authors: Abebaw Assaye, Seiichi Sakurai, Marutama Atsush, Dawit Alemu

Abstract:

Rice is considered as a strategic agricultural commodity targeting national food security and import substitution in Ethiopia and diverse measures are put in place a number of initiatives to ensure the growth and development of rice sector in the country. This study assessed factors that influence smallholder farmers' level of rice commercialization in Ethiopia. The required data were generated from 594 randomly sampled rice producers using multi-stage sampling techniques from four major rice-producing regional states. Both descriptive and econometric methods were used to analyze the data. We adopted the ordered probit model to analyze factors determining output commercialization in the rice market. The ordered probit model result showed that the sex of the household head, educational status of the household head, credit use, proportion of irrigated land cultivated, membership in social groups, and land dedicated to rice production were found to influence significantly and positively the probability of being commercial-oriented. Conversely, the age of the household, total cultivated land, and distance to the main market were found to influence negatively. These findings suggest that promoting productivity-increasing technologies, development of irrigation facilities, strengthening of social institutions, and facilitating access to credit are crucial for enhancing the commercialization of rice in the study area. Since agricultural lands are limited, intensified farming through promoting improved rice technologies and mechanized farming could be an option to enhance marketable surplus and increase level of rice market particicpation.

Keywords: rice, commercialization, Tobit, ordered probit, Ethiopia

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8 Hematological Profiles of Visceral Leishmaniasis Patients before and after Treatment of Anti-Leishmanial Drugs at University of Gondar Leishmania Research and Treatment Center Northwest, Ethiopia

Authors: Fitsumbrhan Tajebe, Fadil Murad, Mitikie Tigabie, Mareye Abebaw, Tadele Alemu, Sefanit Abate, Rezika Mohammedw, Arega Yeshanew, Elias Shiferaw

Abstract:

Background: Visceral leshimaniasis is a parasitic disease characterized by a systemic infection of phagocytic cells. Hematological parameters of these patients may be affected by the progress of the disease or treatment. Thus, the current study aimed to assess the hematological profiles of visceral leishmaniasis patients before and after treatment. Method: An institutional based retrospective cohort study was conducted among visceral leishmaniasis patients at University of Gondar Comprehensive Specialized Referral Hospital Leishmaniasis Research and Treatment Center from 2013 to 2018. Hematological profiles before initiation and after completion of treatment were extracted from registration book. Descriptive statics was presented using frequency and percentage. Paired t-test and Wilcoxon Signed rank test were used for comparing mean difference for normally and non- normally distributed data, respectively. Spearman and Pearson correlation analysis was used to describe the correlation of hematological parameters with different variables. P value < 0.05 was considered as statistically significant. Result: Except absolute nerutrophil count, post treatment hematological parameters show a significant increment compared to pretreatment one. The prevalence of anemia, leucopenia and thrombocytopenia was 85.5%, 83.4% and 75.8% prior to treatment and it was 58.3%, 38.2% and 19.2% after treatment, respectively. Moreover, parasite load of the disease showed statistically significant negative correlation with hematological profiles mainly with white blood cell and red blood cell. Conclusion: Majority of hematological profiles of patients with active VL have been restored after treatment, which might be associated with treatment effect on parasite proliferation and concentration of parasite in visceral organ, which directly affect hematological profiles.

Keywords: visceral leshimaniasis, hematological profile, anti-leshimanial drug, Gondar

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7 Reconceptualizing Human Trafficking: Revealings of the Experience of Ethiopian Migrant Returnees

Authors: Waganesh Zeleke, Abebaw Minaye

Abstract:

This study examined the act, means, and purpose of human trafficking in the case of Ethiopian migrant returnees from the Middle East and South Africa. Using a questionnaire survey data was gathered from 1078 returnees. Twelve focus group discussions were used to solicit detailed experience of returnee about the process of their 'unsafe' immigration. Both quantitative and qualitative analysis results revealed that against the mainstream thinking of human trafficking means such as forcing, coercing, abducting or threatening, traffickers used 'victims’ free will' means by providing false promises to and capitalizing on the vulnerability of migrants. The migrants’ living condition including unemployment, ambitious view to change their life, and low level of risk perception were found to be risk factors which made them vulnerable and target of the brokers and smugglers who served as a catalyst in the process of their 'unsafe' migration. Equal to the traffickers/brokers/agency, the migrants’ family, friends and Ethiopian embassies contributed to the deplorable situation of migrant workers. 64.4% of the returnees reported that their migration is self-initiated, and 20% reported peer pressure and 13.8 percent reported family pressure, and it is only 1.8% who reported having been pushed by brokers. The findings revealed that 69.5% of the returnees do not know about the lifestyle and culture of the host community before their leave. In a similar vein, 50.9% of the returnees reported that they do not know about the nature of the work they are to do and their responsibilities. Further, 81% of the returnees indicated that the pre-migration training they received was not enough in equipping them with the required skill. Despite the returnees experiences of various forms of abuse and exploitation in the journey and at the destination they still have a positive attitude for migration (t=9.7 mean of 18.85 with a test value of 15). The returnees evaluated the support provided by sending agencies and Ethiopian embassies in the destination to be poor. 51.8% of the migrants do not know the details of the contract they signed during migration. Close to 70% of the returnees expressed that they had not got any legal support from stakeholders when they faced problems. What is more is that despite all these 27.9% of the returnees indicated re-immigrating as their plan. Based on these findings on the context and experience of Ethiopian migrant returnees, implications for training, policy, research, and intervention are discussed.

Keywords: trafficking, migrant, returnee, Ethiopia, experience, reconceptualizing

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6 Assessing Impacts of Climate Variability and Change on Water Productivity and Nutrient Use Efficiency of Maize in the Semi-arid Central Rift Valley of Ethiopia

Authors: Fitih Ademe, Kibebew Kibret, Sheleme Beyene, Mezgebu Getnet, Gashaw Meteke

Abstract:

Changes in precipitation, temperature and atmospheric CO2 concentration are expected to alter agricultural productivity patterns worldwide. The interactive effects of soil moisture and nutrient availability are the two key edaphic factors that determine crop yield and are sensitive to climatic changes. The study assessed the potential impacts of climate change on maize yield and corresponding water productivity and nutrient use efficiency under climate change scenarios for the Central Rift Valley of Ethiopia by mid (2041-2070) and end century (2071-2100). Projected impacts were evaluated using climate scenarios generated from four General Circulation Models (GCMs) dynamically downscaled by the Swedish RCA4 Regional Climate Model (RCM) in combination with two Representative Concentration Pathways (RCP 4.5 and RCP8.5). Decision Support System for Agro-technology Transfer cropping system model (DSSAT-CSM) was used to simulate yield, water and nutrient use for the study periods. Results indicate that rainfed maize yield might decrease on average by 16.5 and 23% by the 2050s and 2080s, respectively, due to climate change. Water productivity is expected to decline on average by 2.2 and 12% in the CRV by mid and end centuries with respect to the baseline. Nutrient uptake and corresponding nutrient use efficiency (NUE) might also be negatively affected by climate change. Phosphorus uptake probably will decrease in the CRV on average by 14.5 to 18% by 2050s, while N uptake may not change significantly at Melkassa. Nitrogen and P use efficiency indicators showed decreases in the range between 8.5 to 10.5% and between 9.3 to 10.5%, respectively, by 2050s relative to the baseline average. The simulation results further indicated that a combination of increased water availability and optimum nutrient application might increase both water productivity and nutrient use efficiency in the changed climate, which can ensure modest production in the future. Potential options that can improve water availability and nutrient uptake should be identified for the study locations using a crop modeling approach.

Keywords: crop model, climate change scenario, nutrient uptake, nutrient use efficiency, water productivity

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5 Evaluating the Effect of Climate Change and Land Use/Cover Change on Catchment Hydrology of Gumara Watershed, Upper Blue Nile Basin, Ethiopia

Authors: Gashaw Gismu Chakilu

Abstract:

Climate and land cover change are very important issues in terms of global context and their responses to environmental and socio-economic drivers. The dynamic of these two factors is currently affecting the environment in unbalanced way including watershed hydrology. In this paper individual and combined impacts of climate change and land use land cover change on hydrological processes were evaluated through applying the model Soil and Water Assessment Tool (SWAT) in Gumara watershed, Upper Blue Nile basin Ethiopia. The regional climate; temperature and rainfall data of the past 40 years in the study area were prepared and changes were detected by using trend analysis applying Mann-Kendall trend test. The land use land cover data were obtained from land sat image and processed by ERDAS IMAGIN 2010 software. Three land use land cover data; 1973, 1986, and 2013 were prepared and these data were used for base line, model calibration and change study respectively. The effects of these changes on high flow and low flow of the catchment have also been evaluated separately. The high flow of the catchment for these two decades was analyzed by using Annual Maximum (AM) model and the low flow was evaluated by seven day sustained low flow model. Both temperature and rainfall showed increasing trend; and then the extent of changes were evaluated in terms of monthly bases by using two decadal time periods; 1973-1982 was taken as baseline and 2004-2013 was used as change study. The efficiency of the model was determined by Nash-Sutcliffe (NS) and Relative Volume error (RVe) and their values were 0.65 and 0.032 for calibration and 0.62 and 0.0051 for validation respectively. The impact of climate change was higher than that of land use land cover change on stream flow of the catchment; the flow has been increasing by 16.86% and 7.25% due to climate and LULC change respectively, and the combined change effect accounted 22.13% flow increment. The overall results of the study indicated that Climate change is more responsible for high flow than low flow; and reversely the land use land cover change showed more significant effect on low flow than high flow of the catchment. From the result we conclude that the hydrology of the catchment has been altered because of changes of climate and land cover of the study area.

Keywords: climate, LULC, SWAT, Ethiopia

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4 Application of DSSAT-CSM Model for Estimating Rain-Water Productivity of Maize (Zea Mays L.) Under Changing Climate of Central Rift Valley, Ethiopia

Authors: Fitih Ademe, Kibebew Kibret, Sheleme Beyene, Mezgebu Getnet, Gashaw Meteke

Abstract:

Pressing demands for agricultural products and its associated pressure on water availability in the semi-arid areas demanded information for strategic decision-making in the changing climate conditions of Ethiopia. Availing such information through traditional agronomic research methods is not sufficient unless supported through the application of decision-support tools. The CERES (Crop Environmental Resource Synthesis) model in DSSAT-CSM was evaluated for estimating yield and water productivity of maize under two soil types (Andosol and Luvisol) of the Central Rift Valley of Ethiopia. A six-year data (2010 – 2017) obtained from national fertilizer determination experiments were used for model evaluation. Pertinent statistical indices were employed to evaluate model performance. Following model evaluation, yield and rain-water productivity of maize was assessed for the baseline (1981-2010) and future climate (2050’s and 2080’s) scenario. The model performed well in predicting phenology, growth, and yield of maize for the different seasons and phosphorous rates. A good agreement between simulated and observed grain yield was indicated by low values of the RMSE (0.15 - 0.37 Mg/ha) and other indices for the two soil types. The evaluated model predicted a decline in the potential (23.8 to 26.7% at Melkassa and from 21.7 to 26.1% at Ziway under RCP4.5 and RCP8.5 climate change scenarios, respectively) and water-limited yield (15 to 18.3% at Melkassa and by 6.5 to 10.5% at Ziway) in the mid-century due to climate change. Consequently, a decline in water productivity was projected in the future periods that necessitate availing options to improve water productivity in the region. In conclusion, the DSSAT-CERES-maize model can be used to simulate maize (Melkassa-2) phenology, growth and grain yield, as well as simulate water productivity under different management scenarios that can help to identify options to improve water productivity in the changing climate of the semi-arid central Rift valley of Ethiopia.

Keywords: andosol, CERES-maize, luvisol, model evaluation, water productivity

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3 Yield Level, Variability and Yield Gap of Maize (Zea Mays L.) Under Variable Climate Condition of the Semi-arid Central Rift Valley of Ethiopia

Authors: Fitih Ademe, Kibebew Kibret, Sheleme Beyene, Mezgebu Getnet, Gashaw Meteke

Abstract:

Soil moisture and nutrient availability are the two key edaphic factors that affect crop yields and are directly or indirectly affected by climate variability and change. The study examined climate-induced yield level, yield variability and gap of maize during 1981-2010 main growing season in the Central Rift Valley (CRV) of Ethiopia. Pearson correlation test was employed to see the relationship between climate variables and yield. The coefficient of variation (CV) was used to analyze annual yield variability. Decision Support System for Agro-technology Transfer cropping system model (DSSAT-CSM) was used to simulate the growth and yield of maize for the study period. The result indicated that maize grain yield was strongly (P<0.01) and positively correlated with seasonal rainfall (r=0.67 at Melkassa and r = 0.69 at Ziway) in the CRV while day temperature affected grain yield negatively (r= -0.44) at Ziway (P<0.05) during the simulation period. Variations in total seasonal rainfall at Melkassa and Ziway explained 44.9 and 48.5% of the variation in yield, respectively, under optimum nutrition. Following variation in rainfall, high yield variability (CV=23.5%, Melkassa and CV=25.3%, Ziway) was observed for optimum nutrient simulation than the corresponding nutrient limited simulation (CV=16%, Melkassa and 24.1%, Ziway) in the study period. The observed farmers’ yield was 72, 52 and 43% of the researcher-managed, water-limited and potential yield of the crop, respectively, indicating a wide maize yield gap in the region. The study revealed rainfed crop production in the CRV is prone to yield variabilities due to its high dependence on seasonal rainfall and nutrient level. Moreover, the high coefficient of variation in the yield gap for the 30-year period also foretells the need for dependable water supply at both locations. Given the wide yield gap especially during lower rainfall years across the simulation periods, it signifies the requirement for a more dependable application of irrigation water and a potential shift to irrigated agriculture; hence, adopting options that can improve water availability and nutrient use efficiency would be crucial for crop production in the area.

Keywords: climate variability, crop model, water availability, yield gap, yield variability

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2 Optimization of MAG Welding Process Parameters Using Taguchi Design Method on Dead Mild Steel

Authors: Tadele Tesfaw, Ajit Pal Singh, Abebaw Mekonnen Gezahegn

Abstract:

Welding is a basic manufacturing process for making components or assemblies. Recent welding economics research has focused on developing the reliable machinery database to ensure optimum production. Research on welding of materials like steel is still critical and ongoing. Welding input parameters play a very significant role in determining the quality of a weld joint. The metal active gas (MAG) welding parameters are the most important factors affecting the quality, productivity and cost of welding in many industrial operations. The aim of this study is to investigate the optimization process parameters for metal active gas welding for 60x60x5mm dead mild steel plate work-piece using Taguchi method to formulate the statistical experimental design using semi-automatic welding machine. An experimental study was conducted at Bishoftu Automotive Industry, Bishoftu, Ethiopia. This study presents the influence of four welding parameters (control factors) like welding voltage (volt), welding current (ampere), wire speed (m/min.), and gas (CO2) flow rate (lit./min.) with three different levels for variability in the welding hardness. The objective functions have been chosen in relation to parameters of MAG welding i.e., welding hardness in final products. Nine experimental runs based on an L9 orthogonal array Taguchi method were performed. An orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) are employed to investigate the welding characteristics of dead mild steel plate and used in order to obtain optimum levels for every input parameter at 95% confidence level. The optimal parameters setting was found is welding voltage at 22 volts, welding current at 125 ampere, wire speed at 2.15 m/min and gas flow rate at 19 l/min by using the Taguchi experimental design method within the constraints of the production process. Finally, six conformations welding have been carried out to compare the existing values; the predicated values with the experimental values confirm its effectiveness in the analysis of welding hardness (quality) in final products. It is found that welding current has a major influence on the quality of welded joints. Experimental result for optimum setting gave a better hardness of welding condition than initial setting. This study is valuable for different material and thickness variation of welding plate for Ethiopian industries.

Keywords: Weld quality, metal active gas welding, dead mild steel plate, orthogonal array, analysis of variance, Taguchi method

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1 The Politics of Identity and Retributive Genocidal Massacre against Chena Amhara under International Humanitarian Law

Authors: Gashaw Sisay Zenebe

Abstract:

Northern-Ethiopian conflict that broke out on 04 November 2020 between the central government and TPLF caused destruction beyond imagination in all aspects; millions of people have been killed, including civilians, mainly women, and children. Civilians have been indiscriminately attacked simply because of their ethnic or religious identity. Warrying parties committed serious crimes of international concern opposite to International Humanitarian Law (IHL). A House of People Representatives (HPR) declared that the terrorist Tigrean Defense Force (TDF), encompassing all segments of its people, waged war against North Gondar through human flooding. On Aug 30, 2021, after midnight, TDF launched a surprise attack against Chena People who had been drunk and deep slept due to the annual festivity. Unlike the lowlands, however, ENDF conjoined the local people to fight TDF in these Highland areas. This research examines identity politics and the consequential genocidal massacre of Chena, including its human and physical destructions that occurred as a result of the armed conflict. As such, the study could benefit international entities by helping them develop a better understanding of what happened in Chena and trigger interest in engaging in ensuring the accountability and enforcement of IHL in the future. Preserving fresh evidence will also serve as a starting point on the road to achieving justice either nationally or internationally. To study the Chena case evaluated against IHL rules, a combination of qualitative and doctrinal research methodology has been employed. The study basically follows a unique sampling case study which has used primary data tools such as observation, interview, key-informant interview, FGD, and battle-field notes. To supplement, however, secondary sources, including books, journal articles, domestic laws, international conventions, reports, and media broadcasts, were used to give meaning to what happened on the ground in light of international law. The study proved that the war was taking place to separate Tigray from Ethiopia. While undertaking military operations to achieve this goal, mass killings, genocidal acts, and war crimes were committed over Chena and approximate sites in the Dabat district of North Gondar. Thus, hundreds of people lost their lives to the brutalities of mass killings, hundreds of people were subjected to a forcible disappearance, and tens of thousands of people were forced into displacement. Furthermore, harsh beatings, forced labor, slavery, torture, rape, and gang rape have been reported, and generally, people are subjected to pass cruel, inhuman, and degrading treatment and punishment. Also, what is so unique is that animals were indiscriminately killed completely, making the environment unsafe for human survival because of pollution and bad smells and the consequent diseases such as Cholera, Flu, and Diarrhea. In addition to TDF, ENDF’s shelling has caused destruction to farmers’ houses & claimed lives. According to humanitarian principles, acts that can establish MACs and war crimes were perpetrated. Generally, the war in this direction has shown an absolute disrespect for international law norms.

Keywords: genocide, war crimes, Tigray Defense Force, Chena, IHL

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