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Operative estimation of global horizontal irradiance using transfer functions through network types of artificial neural network in some selected sites in North-East Ethiopia: assessment and comparison

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Heliyon 2025年第10期11卷

作者： Woldegiyorgis, Tegenu Argaw Assamnew, Abera Debebe Benti, Natei Ermias Desalegn, Gezahegn Assefa Anose, Fikru Abiko Mossie, Sentayehu Yigzaw Department of Physics College of Natural Sciences Wollo University P.O. Box 1145 Dessie Ethiopia Computational Data Science Program College of Natural and Computational Sciences Addis Ababa University P. O. Box 1176 Addis Ababa Ethiopia Department of Physics College of Natural and Computational Sciences Wolkite University Wolkite Ethiopia

The estimation of global horizontal irradiance (GHI) for a specific location is crucial to the design, modeling, and effective operation of photovoltaic (PV) and solar thermal energy conversion systems. This study aims to predict the monthly average daily and monthly average GHI for three locations in Ethiopia (Kemissie, Haik, and Woldiya) using artificial neural networks (ANNs) with various activation functions. Days of the year, elevation, and average values (maximum and minimum temperatures, surface pressure, wind speed, relative humidity, wind direction, and precipitation) were fed into the ANN during training. For the prediction of monthly average daily GHI, the CFBP-tansig, FFBP-tansig, and FFBP-logsig networks proved to be the most accurate. Likewise, for monthly average GHI prediction, the FFBP-tansig, CFBP-tansig, and LR-tansig networks exhibited the best performance. The daily and monthly GHI predictions achieved RMSE values ranging from 0.00058 to 0.04042, with correlation coefficients (r) between 0.95417 and nearly 1.0. In comparison, traditional methods showed RMSE values between 0.1 and 0.2, indicating that the ANN models provided up to 80 % better accuracy. The EBP-purelin, CFBP-purelin, and LR-purelin models were less effective, with RMSE values between 0.13815 and 0.17307, and r from 0.91153 to 0.96719. Among the studied locations, Kemissie exhibited the highest GHI potential, emphasizing the region's significant capability for solar energy generation in Ethiopia. © 2025 The Authors

关键词： Activation function Artificial neural network Global horizontal irradiance Network types Prediction

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Molecular Genetic Diversity of Plectranthus edulis (Vatke) Agnew as Revealed by Inter Simple Sequence Repeat Markers

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Proceedings of the National Academy of sciences India Section B - Biological sciences 2021年第2期91卷 361-371页

作者： Shiferaw, Ijara Feyissa, Tileye Petros, Yohannes College of Natural Science Salale University P.O. Box 245 Fitche Ethiopia Institute of Biotechnology Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia Department of Microbial Cellular and Molecular Biology College of Natural and Computational Sciences Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia College of Natural and Computational Sciences Haramaya University Haramaya Dire Dawa Ethiopia

Plectranthus edulis (Vatke) Agnew is an underutilized and neglected ancient Ethiopian indigenous annual tuber crop. Very limited research has been done to improve this crop especially in the area of molecular genetic diversity. Therefore, this study was aimed to assess the genetic diversity of this crop using ISSR markers. Fourteen ISSR primers were screened, and four polymorphic and reproducible primers were selected. These primers generated a total of 46 scorable bands of which 42 were polymorphic. Primer UBC-880 showed 100% polymorphism, and a unique band in some individuals was observed. Within-population diversity ranged from 41.30% to 65.22% with overall percentage of polymorphic loci of 91.30%, Nei’s gene diversity of 0.18–0.30 with overall diversity of 0.33, Shannon information index of 0.25–0.39 with overall index of 0.48, and 74.23% within-population variation was detected. Sodo Zuria, Gojam-II and Areka populations showed the highest diversity, whereas the lowest was exhibited by Nekemte. According to Jaccard’s pairwise similarity coefficient, Ambo and Sodo Zuria were most related populations exhibiting 0.648 similarity coefficient, and Gojam-I and Sodo Zuria were the most distantly related populations with similarity coefficient of 0.489. Wolaita and Wollega populations showed the highest genetic diversity so that these populations should be considered as the primary sites in designing conservation strategies for this crop. © 2021, The National Academy of sciences, India.

关键词： Genetic variation Molecular markers Polymorphism Population structure

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Effects of Environmental and Disturbance Factors on Plant Community Distribution in Tropical Moist Afromontane Forests, South-West Ethiopia

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International Journal of Forestry Research 2023年第1期2023卷

作者： Tadese, Semegnew Soromessa, Teshome Gebeyehu, Getaneh Addis Ababa University College of Natural and Computational Sciences Centre for Environmental Science Addis Ababa Ethiopia Injibara University Department of Biology Injibara Ethiopia

This study was carried out to investigate the effects of environmental and disturbance factors on plant community distribution in the Majang Forest Biosphere Reserve (MFBR) in south-west Ethiopia. A systematic sample design was conducted to collect vegetation and environmental factors in four study sites. In a nested plot design, the vegetation data were collected from 140 main plots, i.e., 400 m2 (trees), 25 m2 subplots (shrubs, lianas, seedlings, and saplings), and 1 m2 (herbs), respectively. The plant community classification was performed using agglomerative hierarchical cluster analysis (Ward's Linkage method) in R software (version 4.0.1). The distribution of plant communities along an environmental gradient was computed using canonical correspondence analysis (CCA). In this study, a total of 15 (9.5%) endemic plant species were recorded in MFBR. Four plant community types were identified, and these were Celtis zenkeri-Blighia unijugata, Pouteria altissima-Lecaniodiscus fraxinifolius, Antiaris toxicaria-Celtis toka, and Dracaena afromontana-Cyathea manniana. Environmental and disturbance factors, such as elevations, slopes, harvesting indexes, soil pH, silt, and herbaceous cover, were the most important for determining plant community distribution in the area. Elevation and slope were found to have a significant (P < 0.05) negative and positive relationship with species diversity and richness, respectively. Therefore, the finding of this study provides baseline information that could be necessary for making further conservation and management in MFBR. © 2023 Semegnew Tadese et al.

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Physicochemical characterization and heavy metals analysis from industrial discharges in Upper Awash River Basin, Ethiopia

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Toxicology Reports 2022年 9卷 1297-1307页

作者： Dessie, Bitew K. Tesema, Bezaye Asegide, Endaweke Tibebe, Degefie Alamirew, Tena Walsh, Claire L. Zeleke, Gete Water and Land Resource Centre of Addis Ababa University Addis Ababa Ethiopia Ethiopian Institute of Water Resources Addis Ababa University Ethiopia College of Natural and Computational Sciences University of Gondar P.O.Box 196 Gondar Ethiopia ARUA Water CoE Institute for Water Research Rhodes University South Africa School of Engineering Newcastle University Newcastle upon Tyne NE1 7RU United Kingdom Adama Science and Technology University School of Architecture and Engineering Ethiopia

The recent expansion of industries in addis ababa is causing additional environmental pollution through wastewater discharges;this is becoming a critical concern. addis ababa is located in the upper Awash River basin, and is the main source of industrial pollutants to the river. In this study, physicochemical parameters, nutrients and heavy metal content of wastewaters released from 16 factories, 6 tanneries, 6 beverages and 4 diverse factories, and the Akaki-Kality central wastewater treatment plant in addis ababa, were sampled to assess the level of pollutants. Heavy metals were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Analysis of nutrients were conducted using Palintest Photometer. Physicochemical characteristics were measured either in situ using a portable micro meter or in the laboratory. Among the measured physicochemical properties, critical issues were observed with electrical conductivity, total dissolved solids and total hardness. Effluents from all of the tanneries, and a number of other factories, were found at levels higher than the maximum limits of various guideline standards. In addition, samples from two of the tanneries (T1 and T5), two beverage factories (B3 and B6) and the central wastewater treatment plant showed elevated concentrations of PO₄^3-, which violated the limit (10 mg/l) set by Environmental Protection Agency of Ethiopia (ETHEPA). The two tanneries (T1 and T5) also contained higher SO₄^2- than the guideline limit of 1000 mg/l. On the other hand, only one factory, one brewery (B3), exhibited NO₃^- above the standard limit of 20 mg/l. Whereas NH₃, NH₄⁺, Cl^-, S^2- and NO₂^- were within the limits in all of the samples. Severe pollution was found in wastewaters from tanneries, where half of them (T1, T5 and T6) contained Cr beyond the maximum limit of 2000 µg

关键词： addis ababa Effluents Heavy metals ICP-OES Nutrients Photometer 7500

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Analysis of Spatio-Temporal Precipitation and Temperature Variability and Trend Over Sudd-Wetland, Republic of South Sudan

SSRN

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SSRN 2023年

作者： Zeleke, Tadesse Terefe Lukwasa, Andu Zakaria Wani Beketie, Kassahun Ture Ayal, Desalegn Yayeh Centre for Environmental Science College of Natural and Computational Sciences Addis Ababa University Ethiopia Institute of Geophysics Space Science and Astronomy Atmospheric and Oceanic Science Addis Ababa University Ethiopia Center for Food Security Studies College of Development Studies Addis Ababa University Ethiopia School of Arts and Humanities Department of Geography University of Juba Ssd

The Sudd Wetland, which supports millions of pastoralists and farmers, as well as the internationally renowned Ramsar Wetland, are under pressure from population growth and climate change extremes such as flooding and drought. Using the Climate Hazards Group Infrareds Precipitation with Station (CHIRPS) and Climate Research Unit (CRU-TS4.06) datasets, this study investigates the spatiotemporal trend and variability of precipitation and temperature. As a result, descriptive statistics were used to describe the spatiotemporal behavior of precipitation and temperature. The Rotated Empirical Orthogonal Function (REOF) was used to detect the spatiotemporal variability of precipitation. The person correlation method was used to investigate the relationship between SST and precipitation. The results revealed that Sudd-wetland receives1910 mm mean spatial annual precipitation and experienced 36°C mean annual temperature with high spatio-temporal variations. It receives the highest precipitation in summer season followed by autumn and spring. The precipitation amount decreases towards the north in all seasons. The Sudd wetland has been affected by prolonged drought and frequent flood events alternatively. The prolonged drought linking with the shrinking of the wetland are potential threats to the farmers and pastoralists to adapt the changing climate. Hence, it is imperative to systematically analyze the wetland ecosystem from different dimensions and adjust the livelihood settings of the people in to less climate sensitive activities. Therefore, we suggest in depth drought and flood risk evaluation and implementation of realistic adaptation strategy to sustain the ecological and economic benefit of the wetland. © 2023, The Authors. All rights reserved.

关键词： Drought

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Leakage and abutment slope stability analysis of Arjo Didesa dam site, western Ethiopia

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Arabian Journal of Geosciences 2022年第19期15卷 1-17页

作者： Asfaw, Legesse Meten, Matebie Garo, Tola Department of Geology College of Applied Sciences Addis Ababa Science and Technology University Addis Ababa Ethiopia Department of Geology College of Natural and Computational Science Bule Hora University Bule Hora Ethiopia Mineral Exploration Extraction and Processing Center of Excellence Addis Ababa Science and Technology University Addis Ababa Ethiopia Department of Applied Geology School of Applied Natural Science Adama Science and Technology University Adama Ethiopia

Arjo Didesa dam is located in western Ethiopia which is designed for irrigation purposes to improve the food security problem in the country. This site is characterized by a complex geological and structural setup that makes it susceptible to engineering geological problems of leakage and slope instability. This study is, therefore, aimed at evaluating the leakage and abutment slope stability of the dam site. The leakage evaluation was done based on results obtained from the Lugeon tests, while slope stability analysis was performed using the kinematic method, limit equilibrium method (LEM), and finite element method (FEM). From the Lugeon tests conducted along the dam axis, more than 57% showed a potential for excessive leakage which needs grouting to control leakage. From these percentages with more than 3 Lugeon units (Lu), about 19.04% were classified into high and very high permeability classes. This indicates that rock masses along the dam axis are mostly cut by interconnected open joints. Slope stability analysis through kinematic analysis showed that some slope sections of both abutments are unstable for a planar mode of failure. Further stability analysis using LEM for a planar mode of failure revealed the presence of potentially unstable slopes at saturated conditions. Moreover, both LEM and FEM showed that some slope sections of both abutments are unstable for a circular mode of failure at saturated conditions with the factor of safety (FOS) and stress reduction factor (SRF) as low as 0.1 and 0.132, respectively. The results from slope stability analysis indicated that the water pressure through seepage is the major causative factor of slope instability. Hence, curtain grouting to the depths of 40 m at the left abutment, 53 m at the central foundation, and 43 m at the right abutment was recommended to control the leakage problem. Moreover, removal of overhanging rocks and slope angle reduction and applying rock bolts and inserting drain hol

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Effect of Forest Management on Carbon Stock of Tropical Moist Afromontane Forest

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International Journal of Forestry Research 2022年第1期2022卷

作者： Daba, Damena Edae Dullo, Bikila Workineh Soromessa, Teshome Center for Environmental Science College of Natural and Computational Sciences Addis Ababa University Addis Ababa Ethiopia Plant Biology and Biodiversity Management College of Natural and Computational Sciences Addis Ababa University Addis Ababa Ethiopia

Moist tropical forests have a significant role in provisioning and regulating ecosystem services. However, these forests are under threat of deforestation and forest degradation. In Ethiopia, the moist evergreen Afromontane forests have the potential for carbon storage and support a high diversity of plant species. However, it is under severe threat of deforestation and *** investigation was conducted to obtain adequate information on the carbon stock potential of the moist Afromontane forest of southwestern Ethiopia. A comparison of carbon stock was conducted between disturbed and undisturbed forests. A systematic sampling design was applied for recording woody species and soil data. A total of 100 main plots of 400 m2 were laid to record trees and shrubs with a diameter at breast height (DBH) ≥ 5 cm. The soil data were collected from 1 m2 subplots established at the four corners and the center of each main plot. The DBH and height were measured to calculate the aboveground carbon of trees and shrubs with DBH ≥ 5 cm. A total of 68 tree and shrub species belonging to 59 genera and 33 families were recorded. The mean carbon stock density was 203.80 ± 12.38 t·ha-1 (aboveground carbon stock) and 40.76 ± 2.47 t·ha-1 (belowground carbon stock). The highest proportion of aboveground carbon (t·ha-1) (42.34%) was contributed by a few tree individuals with DBH > 70 cm. The soil organic carbon stock (SOCS) (t·ha-1) for the depth of 0-30 cm is ranging from 58.97 to 198.33 across plots;the mean is 117.16 ± 3.15. The carbon stored in the moist Afromontane forest indicates its huge potential for climate change mitigation. Therefore, for the enhancement of forest biodiversity and carbon sequestration effective conservation measure and sound management approach is essential. © 2022 Damena Edae Daba et al.

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The Golden Afromontane ecosystems at cross-road: Wetland-based upstream-downstream linkage in Genale Dawa River Basin

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Heliyon 2025年第2期11卷 e41658页

作者： Temesgen, Habtamu Ketema, Haile Kebede, Gezahegn Woldemariyam, Fikadu Tesfaye, Gebremedihin Dilla University College of Agriculture and Natural Resource Department of Natural Resource Management Dilla Ethiopia Adama Science and Technology University College of Natural and Computational Science Department of Applied Geology Adama Ethiopia Addis Ababa University Institute of Water Resource Addis Ababa Ethiopia

Understanding the relationship between land use and land cover (LULC) change and wetland-based ecosystem services (WESs) is crucial for sustaining wetlands and maintaining hydrological connectivity in the Genale-Dawa River Basin (GDRB). While the quantification of LULC change has received considerable emphasis, WESs are often overlooked in this region. This research aims to analyze LULC change and estimate the potential ecosystem services (ESs) provided by the GDRB. Data were collected through field observations, focus group discussions, and key informant interviews, with respondents selected using simple random and purposive sampling techniques. Landsat images between 2005 and 2020, along with documents review, were utilized to generate datasets. A stakeholders’ consultation forum and expert judgment were employed to understand the historical ecology of WESs in the GDRB. Results showed that: (1) LULC change occurred non-linearly in the GDRB, with agricultural land continuously increasing while forestland, woodland, and grassland decreased between 2005 and 2020;(2) the estimated ecosystem service value (ESV) of the GDRB was approximately US $10,360.28 million in 2005 and US $9033.06 million per year in 2020, indicating a decline of 12.81 %, resulting in a total net loss of US $1327.22 million from the basin. Although provisioning ESV has increased, regulating, supporting, and cultural ESVs have experienced significant losses. The increase in provisioning ESV does not compensate for the overall decline in ESVs in the GDRB. Soil compaction in the upstream part of the GDRB has diminished recharge potential and enhanced flooding downstream, jeopardizing sustainable hydrological connectivity in the basin. This situation has placed the basin at risk and at a critical crossroads. Notably, the upstream landscape is now more exposed to anthropogenic pressures than in the past, with clear impacts observed both locally and downstream. Therefore, robust law enforcement and awar

关键词： Afroalpine Afromontane Historical ecology Upstream-downstream Wetland

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Existence and convergence of commutative mappings on some results of fixed point theory in a class of generalized non-expansive mappings

arXiv

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arXiv 2022年

作者： Tadesse, Gezahegn Anberber Department of Mathematics College of Computational and Natural Science Addis Ababa University Ethiopia

In this paper, we introduce a commutative mappings satisfying the class of generalized nonexpansive mappings which is wider than the class of mappings satisfying the condition (C), so called Condition Bγ,µ. The results obtained in this paper extend and generalized non-expansive mappings and other results in this direction. Different properties and some fixed point results for the mappings are obtained *** Codes MCS-class: 47H10 Copyright © 2022, The Authors. All rights reserved.

关键词： Mapping

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Effectiveness of two-stage horizontal subsurface flow constructed wetland planted with Cyperus alternifolius and Typha latifolia in treating anaerobic reactor brewery effluent at different hydraulic residence times

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Environmental Systems Research 2020年第1期9卷 1-15页

作者： Alayu, Ermias Leta, Seyoum Department of Chemistry College of Natural and Computational Sciences Assosa University Assosa Ethiopia Center for Environmental Science College of Natural Science Addis Ababa University Addis Ababa Ethiopia

Background: Agro-industrial wastewaters in Ethiopia cause severe environmental pollution problems. Research evidence showed that anaerobic reactors are good options for the treatment of these wastewaters. But, their final effluent does not meet the discharge standards. Conversely, a series stage horizontal subsurface flow constructed wetland (HSSFCW) system is encouraging for the polishing of anaerobic reactor effluents. However, its treatment efficiency is dependent on hydraulic residence time (HRT). Cyperus alternifolius and Typha latifolia-based wastewater treatment showed good removal efficiencies individually. However, data on their combined treatment effectiveness is negligible. Therefore, this study assesses HRT influences on the treatment effectiveness of a two-stage HSSFCW system planted with these two macrophytes for the polishing of anaerobic reactor brewery effluent. A series connected two-stage HSSFCW unit planted with Cyperus alternifolius and Typha latifolia was built to treat Kombolcha brewery anaerobic reactor effluent. Then, the macrophytes were endorsed to grow with continuous application of diluted brewery effluent from a reservoir tank using gravity force. After dense stand formation, the experiment was initiated to determine the influence of HRTs on the removal efficiency of a complete wetland system. The system was operated sequentially by supplying fixed influent inflow rates of 2791, 1395, 930, 698, and 558 L day−1, respectively, for 1, 2, 3, 4, and 5 days HRT. Both the influent and effluent of the two-stage HSSFCW system were analyzed following common procedures for main brewery pollutants. Result: Results showed that as HRT increased from 1 to 5 days, the effluent pH and temperature were decreased along with enhanced pollutant removals ranging from 47.8–87.2%, 29.2–90.1%, 32.9–77.7%, 16.8–75.4%, and 18.4–76.8% with decreased influent mass loading rates ranging from 26.4–2.1, 64.5–7.3, 11.5–0.8, 5–0.6, and 3.8–0.4 gm−2 day−1, respectively,

关键词： Efficiency

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