Ethiopian Journal of Science and Sustainable Development

Assessment on the Impacts of Vehicle Speed and Slope on Tailpipe Emissions Using Desirability Function Analysis

Amanuel Gebisa Aga — 2024-01-22

Pollutant emissions from vehicles can significantly increase when driving on a road with a positive slope, according to previous studies. In internal combustion engines, minimizing tailpipe emissions like carbon monoxide (CO) and hydrocarbon (HC) by using different strategies increases carbon dioxide (CO2). This likely contributes to global warming through the greenhouse effect. This study aimed at determining the effect of road slope and vehicle speeds on tailpipe emissions, such as CO, HC, and CO2. Full factorial analysis was employed for the design of the experiment. An experiment was conducted in Addis Ababa, Ethiopia, using a portable emissions analyser and Global Positioning System (GPS) to collect emissions data from passenger vehicles at a speed of 10, 20, 30, 40, and 50 km/h and road slopes of -2, 0, 2, 4, and 6 degrees. The regression models developed for CO2, CO, and HC were acceptable, with R-squares of 98.0, 92.9, and 84.9 %, respectively. Finally, desirability function analysis was employed to simultaneously optimize the responses to identify optimum points that minimize CO, HC, and CO2 formation. The most preferable speed to simultaneously reduce CO, HC, and CO2 emissions was found to be 40 km/h on a level road and 30 km/hr on a 2-degree road slope with composite desirability of 0.83 and 0.72, respectively. As a conclusion, it is shown that the use of desirability function analysis can effectively be used to identify the optimum driving speed at which CO, HC, and CO2 emissions are minimized simultaneously for the given road slope.

Finding the Values of Trigonometric Function without the Use of Scientific Calculators: The Case of Tangent Function

Tole Fikadu Aga — 2024-01-22

In the realm of calculating trigonometric functions, computing the tangent function with a high degree of accuracy and precision without using scientific calculators has been an area of interest and importance. However, the manual determination of trigonometric values presents a formidable challenge, demanding careful attention to detail and the application of rigorous techniques. In this article, a set of formulas that enable the computation of tangent function values without resorting to scientific calculators are presented. The proposed formulas generate results that exhibit a remarkably high level of accuracy and precision, reproducible up to three decimal places. They are applicable within the degree intervals of 0 -21o, 21-45o and 45-90o. For angles larger than 90 degrees, the unit circle definition of the function was utilized. The paper provides detailed and comprehensive mathematical derivations for each formula corresponding to their respective intervals and conducts a thorough comparison of the obtained results with the pre-existing tangent function values through the utilization of a tabular method of comparison. Considering the high degree of accuracy and precision exhibited by these formulas, their practical adoption by both students and teachers at all levels of academic pursuits are recommended. Overall, the formulas proposed have the potential to facilitate mathematical calculations and scientific research by providing more accurate and efficient means of calculating tangent function values.

First Report of the Larger Grain Borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) from Stored Maize in Ethiopia

Ofgaa Djirata Dako — 2024-01-22

In Ethiopia, over nine million farmers produce maize on about 14% of the total land area. It serves as food and feed. Various arthropod pests destroy maize in traditional storage. Larger grain borer (LGB), Prostephanus truncatus (Horn) is a devastating storage pest that constrain stored maize in Eastern Africa and beyond. This study was aimed at surveying whether the LGB has been infesting stored maize in southern Ethiopia or not. Community based cross sectional survey was conducted in four purposively selected kebeles in Baka Dawula Ari District in South Omo Zone of South Nations, Nationalities and Peoples Regional State. A total of three maize cobs were picked from each type of storage structure in three replications from every study Kebele. Then, the cobs were taken to the Laboratory of Entomology and Vertebrate Zoology of Arba Minch Plant Health Clinic and the pest species were identified by the use of binocular microscope. A total of 11 species of arthropod pests were identified from the stored maize. P. truncatus was found to be one of the most severely damaging of stored maize. This pest was recorded infesting maize grain in Ethiopia for the first time by this study. It is concluded that LGB has already entered into Ethiopia, it has already been established and it is devastating stored maize. Immediate integrated control of the LGB shall be implemented. A survey of countrywide geographical distribution of the LGB shall be held in order to design large-scale management practices of the pest.

Analyzing Faculty Publication Trends and Academic Rank Attainment: Haramaya University in the Spotlight

Chala Mosisa Hunduma — 2024-01-22

This study explores into the evolving landscape of faculty publication and academic rank attainment at Haramaya University. A comprehensive analysis was conducted, aligning the university's faculty promotion criteria with the recent Ministry of Education (MoE) standard, with a specific focus on research output. The research methodology comprised a meticulous examination of university records/archival research, including minutes documented by the university's appointment, promotion, and scholarship committee. In addition, the study enriched its insights through in-depth interviews with faculty members. The investigation explored academic promotion, gender dynamics, and the differentiation between native and expatriate faculty. The findings underscored certain disparities, particularly in terms of fields of study, nationality, and gender. A notable discrepancy was observed, with a higher proportion of male faculty members attaining promotions, a phenomenon more pronounced at elevated academic ranks such as Associate Professor and Full Professor. To address these disparities and nurture a more inclusive research environment, Haramaya university promotion policy may partially help as most of the values is given to publication, which was already fixed by the guideline prepared by Ethiopian MoE. A call for transparent promotion standards, robust mentorship programs, and focused support for women in research and leadership roles emerge as a means to bridge the gender gap in staff promotions. Furthermore, additional research and analysis must be undertaken to attain a more profound understanding of the factors influencing publishing trends, facilitate staff promotions, and ultimately advance the promotion of academic excellence.

Enhancing the Synthesis of Biolubricant from Used Chicken Fat: Optimization of Operating Parameters Using Magnesium Oxide Nanoparticles as a Catalyst and Response Surface Methodology

Yohannes Assefa Degaga — 2024-01-22

In light of the growing concerns regarding the environmental impact and sustainability of mineral oil-based lubricants, the use of biolubricants has been advocated as a renewable alternative. The double transesterification of used chicken fat oil involves two steps of converting the triglycerides into methyl esters (UCFME) using methanol and Magnesium oxide Nano Particles (MgO NPs) as catalyst, and utilizing Trimethylolpropane (TMP) and MgO NPs to produce the final biolubricant (UCFBL). This research aimed to optimize the reaction parameters for the transesterification process involving used chicken fat methyl ester (UCFME) and TMP using response surface methodology. A series of 20 individual experiments were conducted, focusing on the variables of reaction temperature, time, and UCFME-to-TMP molar ratio. Through statistical modeling, it was predicted that the transesterification process would yield a maximum conversion rate of 97.5% under the optimized conditions of a reaction temperature 114 °C, a reaction time 227 minutes, and a UCFME-to-TMP molar ratio 10.5:1. Experimental results, obtained from three independent replicates conducted under these optimal conditions, demonstrated an average yield of 98.3 % for the production of UCFBL, which aligned closely with the model's predicted range of 98.35%. The resultant biolubricant has remarkable lubrication qualities, such as a pour point of -5 °C, flash point of 289°C, viscosity index of 213, and kinematic viscosities (KV) of 38.5 and 9.2 cSt at 40 and 100 °C, respectively. These qualities revealed that the biolubricant generated fulfilled the ISO VG-32 criteria, making it an acceptable replacement for petroleum-based lubricants in industrial machine applications.

Tender/Contract Corruption Crimes in Ethiopia: Evidences from Convicted Court Cases

Afework Alemayehu Gobena — 2024-01-25

In a wider qualitative study concerned with corruption crimes in Ethiopia, there are only 16 which are about tender/contract corruption crimes. This study dealt only with these corruption crimes, based on court case files in which defendants were found guilty. The crimes were committed as medium or top level government and private organizations’ officials competed for livelihood goals. To corruptly increase own income or profit, the officials used authority and qualification, manipulated bureaucratic rules, regulations and decisions. They further exploited the free market (money) economy in which items of exchange are not delivered immediately; illegal means of earning the ‘charming’ money or owning other valuable assets remains unquestioned, self-control and ethical concerns have been minimized. The criminals owned properties contrary to socially approved ways while the high monetary values the crimes involved- one to several millions- implied that the criminals reaped huge amounts of kickbacks. The article further argues that these corruption crimes, though committed for economic benefits, could not be considered economic actions. To minimize tender/contract corruption crimes, it is recommended to reward public officials with “secure existence” by means of salaries regularly revised in accordance with inflation and corruption controlling coercive laws at least partially redirected to social sanctions.

Detection of Emotions in Afan Oromo Social Media Texts Using Deep Learning Method

Sufian Kedir Abdella — 2024-02-06

Emotion analysis in foreign languages is common because of its numerous useful applications in commercial activities and decision-making. However, there was a lack of emotion-detection work for Afan Oromo language. Manually identifying and aggregating millions of social media users' emotions into a swift and effective decision-making process is challenging task. Thus, the main objective of this study was to detect emotion in the Afan Oromo social media texts. To achieve this, state-of-the-art deep learning models, namely convolutional neural networks (CNN), long short-term memory (LSTM), bidirectional long short-term memory (BiLSTM), and hybrid of them (CNN-LSTM and CNN-BiLSTM), were designed and investigated to select the best-suited model for emotion detection in Afan Oromo. Data was collected from official Facebook pages, then manually annotated, and preprocessed by using normalization, tokenization and stop-word removal. Word embedding was used for feature encoding, and Keras Python libraries were employed for implementation. The study’s results revealed that the proposed models performed well with accuracies of 92, 87, 88, 88 and 90 % for CNN, LSTM, BiLSTM, CNN-LSTM, and CNN-BiLSTM, respectively. Thus, the CNN model outperformed all the other models. It was also found out that the CNN model suited and gave a better result when it was worked on a small dataset and a short sequence of texts. The accuracy of the comparatively less performing models, particularly the performance of the hybrid models, can be increased through the construction of sufficient data, because they leverage the benefits of each of them.

Bacterial-resistance, growth and immune competence of Oreochromis niloticus fed Lactobacillus fermentum

Orisanona Olugbenga — 2024-02-09

Aquaculture production can be boosted with enhanced feed efficiency, growth and disease resistance using probiotics. In this study, the effects of Lactobacillus fermentum (LF) probiotic on growth, intestine, immune competence of Oreochromis niloticus, and the resistance to virulent Aeromonas hydrophila were investigated. A basal (LF1) diet (35% crude protein) was formulated and five treatments with L. fermentum included at 1 x 10³cfu/g (LF2), 1 x 10⁵cfu/g (LF3), 1 x 10⁷cfu/g (LF4), 1 x 10⁹cfu/g (LF5) and 1 x 10¹¹cfu/g (LF6). The six diets were each allotted to three groups of Oreochromis niloticus (1.85±0.01g mean weight) for 90 days. After which fish were injected with A. hydrophilia, fed and observed for 15 days. At the end of the 90 days, LF diets fed fish had higher (p<0.05) mean weight gain. Feed conversion ratio and specific growth rate were superior in fish fed LF3 and LF4. Villi height was significantly high in LF3, while microbial loads were more in the guts of fish fed probiotics. Blood packed cell volume and haemoglobin increased significantly in the groups fed LF. Hydrogen peroxide and malondialdehyde reduced significantly (p<0.05) in the liver and kidney of fish fed L. fermentum, while glutathione transferase and glutathione peroxidase activities were increased. The challenge test with virulent Aeromonas hydrophila showed improved resistance in fish fed probiotic. Thus, the study disclosed improved growth performance, enhanced health status and better survival with the supplementation of Lactobacillus fermentum in the diets of Oreochromis niloticus.

Antibacterial and Antioxidant Compounds from Root Extracts of Gloriosa superba Linn: A Combined Experimental and Computational Study

Iman Mustefa — 2024-02-12

Throughout history, medicinal plants have globally served as remedies for various ailments, and diseases. The roots of Gloriosa superba are traditionally used to treat antitumor, antimicrobial, and anti-inflammatory diseases. In this study, the roots of G. superba (320 g) were successively extracted with n-hexane, chloroform, and methanol to afford 530 mg (0.17%), 2.89 g (0.90%), and 17.78 g (5.56%) yields, respectively. Silica gel column chromatographic separation of the combined chloroform and methanol extracts gave 4-methoxy caffeic acid heptyl ester (1), desmosterol (2), 3-hydroxymethyl phenol (3), 3-Hydroxy-5-methoxy-benzoic acid (4), sucrose (5) and rutinose (6). In vitro antibacterial study revealed promising zone of inhibition value by chloroform extract against Klebsiella pneumoniae (13±0.00 mm) compared to gentamicin (15.86±4.67 mm). Desmosterol (2), 3-hydroxymethyl phenol (3), and 3-Hydroxy-5-methoxy-benzoic acid (4) displayed promising zone of inhibition against K. pneumonia (12.33±0.58, 11.33±1.53 and 11.33±1.15 mm, respectively) at 1000 μg/mL compared to gentamycin (15.86±4.67 mm at 100 μg/mL). Promising inhibition zone values were also displayed by desmosterol (2) and 3-Hydroxy-5-methoxy-benzoic acid (4) against Pseudomonas aeruginosa (14±1.00 and 14±1.73 mm, respectively) compared to gentamycin (25±2.52 mm).Chloroform extract displayed 95.14% DPPH radical scavenging value compared to ascorbic acid (96.11%) at 200 μg/mL. Compounds 2 and 4 displayed binding affinities of -7.8 and -6.5 Kcal/mol, respectively, against PqsA protein of P. aeruginosa, compared to amoxicillin (-7.3 kcal/mol). Therefore, the in vitro antibacterial and radical scavenging activity results suggest the potential uses of the root extracts of G. superba as promising antibacterial agents and free radical scavengers.