Ascertaining the source of major dissolved solute and recharge mechanism of groundwater in the Golina River Basin, Northern Ethiopia

Hindeya Gebru^1,2*, Tesfamichael Gebreyohannes², and Ermias Hagos^2
1 Department of Earth Sciences, Samara University, Samara, Ethiopia
² School of Earth Sciences, Mekelle University, Mekelle, Ethiopia
*Corresponding author: hindualem@gmail.com 

This study uses major ions and stable water isotopes to understand the solute acquisition, origin, and recharge mechanisms of groundwater of the alluvial deposits (sand and gravels) and weathered and fractured volcanic rocks aquifers in the Golina River Basin (GRB), Ethiopia. The results of the hydrogeochemistry indicates that the solutes of the groundwater are dominantly acquiring by the natural weathering of Ca²⁺ and M^g2+-rich silicate minerals. The study suggest that groundwater preferentially flow through the basalts and little through the acidic rocks which determine the four groundwater facies (Ca²⁺–HCO₃^-, Mg²⁺–HCO₃^-, Ca²⁺–Mg²⁺–HCO₃^-, and Na⁺–HCO₃^-) in the area. Further, there is an ion exchange between groundwater and its host environment during the movement process, creating disequilibrium within the aquifer. Based on the similarity of their hydrochemical properties, the groundwater in the area is grouped into four major groups and four subgroups. The stable water isotopes results suggest that seasonal variances in the slope and intercepts of the local meteoric water line (LMWL) is associated with changes in meteorology and moisture sources, which underlie the subtle variations in δ¹⁸O and δ²H in precipitation over time and space. The seasonal local meteoric water lines of the Golina River Basin were obtained; resulting δ²H = 7.3±4.4δ¹⁸O +8.8±1 for wet season precipitations (months between June and September) and δ²H = 4.5±3.5δ¹⁸O +11.6±1.1 for dry season precipitations (months between October to May). The study further reveals that groundwater exhibits lower slope (5.1±2) and lower intercept (5.6±0.77) than LMWL and that of GMWL, indicating the evaporation of infiltrating meteoric waters before it joining the aquifer system. Therefore, the present study finds that groundwater is recharged from direct infiltration of the precipitation and recharged from the nearby mountainous regions on west and east of the basin.

Keywords: Solute source, groundwater recharge, stable water isotopes, Golina River Basin

Evaluation of underutilized cultivated Anchote (Coccinia abyssinica (Lam.) Cogn.) accessions in West Shewa Zone, Oromia Regional State, Central Ethiopia

Zinash Teferi Abdena^1* and Mosisa Chewaka Aga^1
1 Ambo University, College of Agriculture and Veterinary Sciences, Ambo, Ethiopia
* Corresponding author Email: Zinashteferiabdena2022@gmail.com 

Abstract
Anchote (Coccinia abyssinica) is an endemic root and tuber crop species of Ethiopia, which belongs to the Cucurbitaceae family. The aim of this study was to assess C. abyssinica accessions to identify better physical adaptability potential and high-yielding in the West Shewa zone, central highland of Ethiopia. Sixteen (16) promising Anchote accessions were planted in a 2m x 2m plot area by using a randomized complete block design, with three replications for three consecutive main rain-fed cropping seasons from 2018-2020 years. In the present study, the statistically analyzed outputs of the measured agronomic parameters of individual accession mean values were varied in the range of seedlings emergency percentage (77-96.13%), vine number per plant (2.34-3.54), vine length per plant (1.99-6.35m), vine internodes length (7.70-11.57cm), number of leaves per plant (116.66-129), Leaf area per plant (92.27-162.8 cm2); storage root diameter (62.35–136.26 cm), storage root dry matter content (5.55-25.14%), total storage root weight per plant (0.41-1.15kg), total storage root yield per hectare (52.25-143.79 tonne/ha), marketable storage root yield per hectare (50.63-143.7 tonne/ha) and unmarketable storage root yields per hectare (0.05–1.62 tonne/ha) were recorded. From this study, six (6) accessions: 223090, 223113, 223086, 223100, 223105, and 223104 were identified as those that produced the highest storage root yield (> 101 tonne/ha), highest marketable storage root yield (> 101 tonne/ha), and highest dry matter content (> 21 %) which indicating a good performance and adaptation in west Shewa central highland of Ethiopia. Therefore, these accessions are suggested to produce and scale up by farmers in the central highland of a country, and other areas of similar agroecological zones.

Keywords: Accessions, Anchote, Coccinia abyssinica, root crops, underutilized crop
 

Assessment of Solar Energy Potential for Solar Cooking - a Case of Daassenech, Ethiopia

Ephrem Milikias Meja^1* and Addisu Bekele Alemayehu^2
1 Department of Mechanical Engineering, Dilla University, Dilla, Ethiopia
² Department of Mechanical Engineering, Adama Science and Technology University, Adama, Ethiopia
*Corresponding author: Ephremm.2013@gmail.com
 

Abstract
The main aim of this paper is to explore the available solar energy potential for the purpose of designing and experimental analysis of small-scale low-cost solar cookers in the Daassenech area. Solar energy evaluation is done based on sunshine data collected from the Ethiopian national metrology agency and other four satellite-based data are analyzed from different freely accessible international databases. The averages of the five solar radiation data sources are used to estimate the solar energy potential of the area. From the estimated solar energy potential of the study area, the maximum global solar radiation is obtained in the month of February (6.563 KW/m²/day) and minimum in the month of July (5.578 KW/m²/day) and the overall annual average daily solar radiation of the area is 6.134 KW/m²/day. Finally, based on the estimated solar energy potential, a small-scale low-cost solar cooker has been designed and tested. Experimental values of the first figure of merits are 0.1349, 0.1238, and 0.1453 for conventional BSC, improved BSC with and without thermal storage, respectively. The second figure of merits of all solar cookers' average values are calculated as 0.524, 0.97, and 1.0964 for conventional box solar cookers, improved solar cookers with thermal energy storage, and ISC without any TES respectively.

Keywords: Solar radiation, solar energy potential, solar cooker, solar thermal system
 

Roles of Botanical Gardens for Conservation and Requirements for their Establishment: Review

Mehari Girmay
Plant Research Directorate, Gullele Botanical Garden, P.O. Box: 153/1029, Addis Ababa, Ethiopia
Corresponding author email: meharirgm@gmail.com

Abstract
Botanical gardens are extremely important institutions that safeguard the environment from everincreasing environmental concerns, educate people about environmental issues, provision of recreational opportunities, conducting of various research and conservations. Their mission is to keep documented collections of living plants for scientific research, conservation, display, and education, but this may vary depending on the resources available and the special interests pursued at each garden. Botanists and gardeners are typically on the staff. Currently, about 3,765 botanical gardens conserve approximately 30% of the species. A wide and distinctive collection of living plants serves as a foundation for research and modern taxonomic studies in morphology, ecology, genetics, systematics, and evolution in the twenty-first-century botanical garden. Furthermore, botanical gardens provide germplasm for the hybridization of species, which allows for the improvement of economically important varieties of flowers, fruits, and vegetable plants. Prior to the establishment of the botanical garden, important components such as site selection, feasibility
study, defined objectives, vision and mission, detailed design, construction specifications, theme stablishment, weeds and pest control links, professional experts, and mode of operation must be considered. This review determines a brief description of the botanical garden, the conditions for establishment, and its role in plant and habitat protection.
 

Keywords: Botanical Garden, Conservation, Ecology, Germplasm, Plants

Study of Organometallic Sensitizer Regeneration Kinetics by Scanning Electrochemical Microscopy

Ataklti Abraha Gebreyohanes^*1 and Getachew Alemu Anshebo¹
College of Natural and Computational Sciences, Department of Physics, Samara University,
Samara, Ethiopia, B.O.Box 132.
*Corresponding author: atklt.physics@gmail.com

Abstract

Organometallic perovskite is used as a sensitizer for nanoporous nickel oxide films in photoelectrochemical solar cell applications. The regeneration kinetics of light-absorbing sensitizer molecules by the organic electrolyte 1-methy-1H-tetrazole-5-thiolate (T-) were studied using scanning electrochemical microscopy's feedback mode (SECM). The approach curves were used to calculate the regeneration rate constants. The rate constants (k_red) for perovskite
and organic dye have been found as 9.98 × 10⁶ mol^-1cm³s^-1 and 4.51 × 10⁵mol^-1cm³s^-1 respectively. Similarly, The absorption cross section (Φhv), for perovskite and organic dye have been found as 6.87 × 10⁶ mol cm² for blue LED and 4.89 × 10⁶ mol cm² for red LED, and 3.56 × 10⁵ mol cm² for blue LED and 2.15 × 10⁵ mol cm² for red LED respectively. Thus, we observed that regeneration parameters of organometallic perovskite were higher than organic dye. Generally, SECM investigation opens a new outlook for p-type dye-sensitized solar cell characterization.

Keywords: Organometallic Perovskite, SECM, Regeneration Parameters, Dye-Sensitized Solar Cells, Organic Dye
 

Study of Organometallic Sensitizer Regeneration Kinetics by Scanning Electrochemical Microscopy

Ataklti Abraha Gebreyohanes^*1 and Getachew Alemu Anshebo¹
College of Natural and Computational Sciences, Department of Physics, Samara University,
Samara, Ethiopia, B.O.Box 132.
*Corresponding author: atklt.physics@gmail.com

Abstract

Organometallic perovskite is used as a sensitizer for nanoporous nickel oxide films in photoelectrochemical solar cell applications. The regeneration kinetics of light-absorbing sensitizer molecules by the organic electrolyte 1-methy-1H-tetrazole-5-thiolate (T-) were studied using scanning electrochemical microscopy's feedback mode (SECM). The approach curves were used to calculate the regeneration rate constants. The rate constants (k_red) for perovskite and organic dye have been found as 9.98 × 10⁶ mol^-1cm³s^-1 and 4.51 × 10⁵mol^-1cm³s^-1 respectively. Similarly, The absorption cross section (Φhv), for perovskite and organic dye have been found as 6.87 × 10⁶ mol cm² for blue LED and 4.89 × 10⁶ mol cm² for red LED, and 3.56 × 10⁵ mol cm² for blue LED and 2.15 × 10⁵ mol cm² for red LED respectively. Thus, we observed that regeneration parameters of organometallic perovskite were higher than organic dye. Generally, SECM investigation opens a new outlook for p-type dye-sensitized solar cell characterization.

Keywords: Organometallic Perovskite, SECM, Regeneration Parameters, Dye-Sensitized Solar Cells, Organic Dye
 

Vegetation Structure and regeneration status of Guard Dry Afromontane Forests in North Western Ethiopia

Yitayih Dagne^1*, Liyew Birhanu^1
1Department of Biology, Debremarkos University, P.O. Box: 269, Debre Markos, Ethiopia.
*Corresponding Author: yitdagne@gmail.com

Abstract
The study was conducted in Guard forest in Dejen district, East Gojam zone, North West Ethiopia, to determine the vegetation structure and regeneration status of Guard Dry Afromontane forests. A systematic sampling technique was used for vegetation data collection. 58 plots each with 400 m² (20 m X 20 m) for trees and shrubs. From each main plot, five subplots 4 m² and 1 m² were laid at the four corners and center of the main sample plot to count saplings and seedlings of woody plant species of the forest. The total species richness was 77 woody species belonging to 60 genera and 36 families. The total basal area of woody species is 20m² ha-1. Tree species such as Ficus vasta had 3.5(18%), Millettia ferruginea 2.52(13%), Ficus sycomorus 1.63(8%), Stereospermum kunthianum 1.14(6%), Croton macrostachyus 0.68 (4%), Ekebergia capensis 0.25(2%) contribute the largest basal area and the remaining species contributed 49% of the total basal area. A total of 805 individuals were counted with a DBH class greater than 2.5 cm within the sampled plots, the highest DBH-class mostly recorded in DBH-Class 1(147.4 ha^-1 (48%) then declined towards the end of DBH-Class-8( 5.6 ha^-1 (2%).The upper story was represented by a height greater than 17m, which accounts for about 20% frequency of the woody species, whereas the middle story ranges from 7 m to 17 m (46.8%) and < 7m (32.8 %%) were constituted by the lower story. The total seedling, sapling, and mature tree densities of the 20 selected plant species were about 47.41 ha^-1, 92.2 ha^-1, and 279.31 individuals per hectare respectively, that shows the regeneration status of the forest is poor because the mature trees are greater than saplings and greater than seedlings.

Keywords: Seedling, Vegetation, Regeneration status, DBH.