Search results for: Anteneh Dagnachew Sewenet

Authors: Anteneh Dagnachew Sewenet, Paola Pisano

Abstract:

The concept of circular economy, circularity, and sustainability are interconnected and promote a more sustainable future. However, previous studies have mainly focused on each concept individually, neglecting the relationships and gaps in the existing literature. This study aims to integrate and link these concepts to expand the theoretical and practical methods of scholars and professionals in pursuit of sustainability. The aim of this systematic literature review is to comprehensively analyze and summarize the interconnections between circular economy, circularity, and sustainability. Additionally, it seeks to develop a conceptual framework that can guide practitioners and serve as a basis for future research. The review employed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. A total of 78 articles were analyzed, utilizing the Scopus and Web of Science databases. The analysis involved summarizing and systematizing the conceptualizations of circularity and its relationship with the circular economy and long-term sustainability. The review provided a comprehensive overview of the interconnections between circular economy, circularity, and sustainability. Key themes, theoretical frameworks, empirical findings, and conceptual gaps in the literature were identified. Through a rigorous analysis of scholarly articles, the study highlighted the importance of integrating these concepts for a more sustainable future. This study contributes to the existing literature by integrating and linking the concepts of circular economy, circularity, and sustainability. It expands the theoretical understanding of how these concepts relate to each other and provides a conceptual framework that can guide future research in this field. The findings emphasize the need for a holistic approach in achieving sustainability goals. The data collection for this review involved identifying relevant articles from the Scopus and Web of Science databases. The selection of articles was made based on predefined inclusion and exclusion criteria. The PRISMA protocol guided the systematic analysis of the selected articles, including summarizing and systematizing their content. This study addressed the question of how circularity is conceptualized and related to both the circular economy and long-term sustainability. It aimed to identify the interconnections between these concepts and bridge the gap in the existing literature. The review provided a comprehensive analysis of the interconnections between the circular economy, circularity, and sustainability. It presented a conceptual framework that can guide practitioners in implementing circular economy strategies and serve as a basis for future research. By integrating these concepts, scholars, and professionals can enhance the theoretical and practical methods in pursuit of a more sustainable future. The findings emphasize the importance of taking a holistic approach to achieve sustainability goals and highlight conceptual gaps that can be addressed in future studies.

Keywords: circularity, circular economy, sustainability, innovation

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Authors: Anteneh Getachew Gebrie, Rabian Wangkeeree

Abstract:

The purpose of this paper is to introduce iterative algorithm solving split system of minimization problem given as a task of finding a common minimizer point of finite family of proper, lower semicontinuous convex functions and whose image under a bounded linear operator is also common minimizer point of another finite family of proper, lower semicontinuous convex functions. We obtain strong convergence of the sequence generated by our algorithm under some suitable conditions on the parameters. The iterative schemes are developed with a way of selecting the step sizes such that the information of operator norm is not necessary. Some applications and numerical experiment is given to analyse the efficiency of our algorithm.

Keywords: Hilbert Space, minimization problems, Moreau-Yosida approximate, split feasibility problem

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Authors: Adine Barett, Jermel Watson, Anteneh Girma, Kacem Thabet

Abstract:

In information security, secure communication of data across networks has always been a problem at the forefront. Transfer of information across networks is susceptible to being exploited by attackers engaging in malicious activity. In this paper, we leverage steganography and cryptography to create a layered security solution to protect the information being transmitted. The first layer of security leverages crypto- graphic techniques to scramble the information so that it cannot be deciphered even if the steganography-based layer is compromised. The second layer of security relies on steganography to disguise the encrypted in- formation so that it cannot be seen. We consider three cryptographic cipher methods in the cryptography layer, namely, Playfair cipher, Blowfish cipher, and Hills cipher. Then, the encrypted message is passed through the least significant bit (LSB) to the steganography algorithm for further encryption. Both encryption approaches are combined efficiently to help secure information in transit over a network. This multi-layered encryption is a solution that will benefit cloud platforms, social media platforms and networks that regularly transfer private information such as banks and insurance companies.

Keywords: cryptography, steganography, layered security, Cipher, encryption

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Authors: Anteneh Mesfin Yeneneh, Abdul Shakoor, Jimoh Adewole, Safinaz Al Balushi, Sara Al Balushi

Abstract:

The research work focuses on exploring better technologies for solar energy storage. The research has the objective of substituting fossil fuels with renewable solar energy technology. This was the reason that motivated the research team to search for alternatives to develop an eco-friendly desalination process, which fully depends on the solar energy source. The Authors also investigated the potential of using different salt mixtures for better solar energy storage and better pure water productivity. Experiments were conducted to understand the impacts of solar energy collection and storage techniques on heat accumulation, heat storage capacity of various compositions of salt mixtures. Based on the experiments conducted, the economic and technical advantages of the integrated water desalination was assessed. Experiments also showed that the best salts with a higher storage efficiency of heat energy are NaCl, KNO3, and MgCl26H2O and polymers such as Poly Propylene and Poly Ethylene Terephthalate.

Keywords: molten salts, desalination, solar energy storage and utilization, polymers

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Authors: Anteneh Wodaje Bayeh, Daniel Manaye Kabtamu, Chen-Hao Wang

Abstract:

As one of the most promising electrochemical energy storage systems, vanadium redox flow batteries (VRFBs) have received increasing attention owing to their attractive features for largescale storage applications. However, their high production cost and relatively low energy efficiency still limit their feasibility. For practical implementation, it is of great interest to improve their efficiency and reduce their cost. One of the key components of VRFBs that can greatly influence the efficiency and final cost is the electrode, which provide the reactions sites for redox couples (VO²⁺/VO₂ + and V²⁺/V³⁺). Carbon-based materials are considered to be the most feasible electrode materials in the VRFB because of their excellent potential in terms of operation range, good permeability, large surface area, and reasonable cost. However, owing to limited electrochemical activity and reversibility and poor wettability due to its hydrophobic properties, the performance of the cell employing carbon-based electrodes remained limited. To address the challenges, we synthesized heteroatom-doped bimetallic oxide grown on the surface of carbon through the one-step approach. When applied to VRFBs, the prepared electrode exhibits significant electrocatalytic effect toward the VO²⁺/VO₂ + and V³⁺/V²⁺ redox reaction compared with that of pristine carbon. It is found that the presence of heteroatom on metal oxide promotes the absorption of vanadium ions. The controlled morphology of bimetallic metal oxide also exposes more active sites for the redox reaction of vanadium ions. Hence, the prepared electrode displays the best electrochemical performance with energy and voltage efficiencies of 74.8% and 78.9%, respectively, which is much higher than those of 59.8% and 63.2% obtained from the pristine carbon at high current density. Moreover, the electrode exhibit durability and stability in an acidic electrolyte during long-term operation for 1000 cycles at the higher current density.

Keywords: VRFB, VO²⁺/VO₂ + and V³⁺/V²⁺ redox couples, graphite felt, heteroatom-doping

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Authors: Daniel Manaye Kabtamu, Anteneh Wodaje Bayeh

Abstract:

With the development and utilization of new energy technology, people’s demand for large-scale energy storage system has become increasingly urgent. Vanadium redox flow battery (VRFB) is one of the most promising technologies for grid-scale energy storage applications because of numerous attractive features, such as long cycle life, high safety, and flexible design. However, the relatively low energy efficiency and high production cost of the VRFB still limit its practical implementations. It is of great attention to enhance its energy efficiency and reduce its cost. One of the main components of VRFB that can impressively impact the efficiency and final cost is the electrode materials, which provide the reactions sites for redox couples (V₂₊/V³⁺ and VO²⁺/VO₂⁺). Graphite felt (GF) is a typical carbon-based material commonly employed as electrode for VRFB due to low-cost, good chemical and mechanical stability. However, pristine GF exhibits insufficient wettability, low specific surface area, and poor kinetics reversibility, leading to low energy efficiency of the battery. Therefore, it is crucial to further modify the GF electrode to improve its electrochemical performance towards VRFB by employing active electrocatalysts, such as less expensive metal oxides. This study successfully fabricates low-cost plate-like bismuth vanadate (BiVO₄) material through a simple one-step hydrothermal route, employed as an electrocatalyst to adorn the GF for use as the negative electrode in VRFB. The experimental results show that BiVO₄-3h exhibits the optimal electrocatalytic activity and reversibility for the vanadium redox couples among all samples. The energy efficiency of the VRFB cell assembled with BiVO₄-decorated GF as the negative electrode is found to be 75.42% at 100 mA cm−2, which is about 10.24% more efficient than that of the cell assembled with heat-treated graphite felt (HT-GF) electrode. The possible reasons for the activity enhancement can be ascribed to the existence of oxygen vacancies in the BiVO₄ lattice structure and the relatively high surface area of BiVO₄, which provide more active sites for facilitating the vanadium redox reactions. Furthermore, the BiVO₄-GF electrode obstructs the competitive irreversible hydrogen evolution reaction on the negative side of the cell, and it also has better wettability. Impressively, BiVO₄-GF as the negative electrode shows good stability over 100 cycles. Thus, BiVO₄-GF is a promising negative electrode candidate for practical VRFB applications.

Keywords: BiVO₄ electrocatalyst, electrochemical energy storage, graphite felt, vanadium redox flow battery

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Authors: Shewit Kidane, Abebe Getahun, Wassie Anteneh, Admassu Demeke, Peter Goethals

Abstract:

We have reviewed major findings of scientific studies on Lake Tana fish resources and their threats. The aim was to provide summarized information for all concerned bodies and international readers to get full and comprehensive picture about the lake’s fish resource and conservation problems. The Lake Tana watershed comprise 28 fish species, of which 21 are endemic. Moreover, Lake Tana is the one among the top 250 lake regions of global importance for biodiversity and it is world recognized migratory birds wintering site. Lake Tana together with its adjacent wetlands provide directly and indirectly a livelihood for more than 500,000 people. However, owing to anthropogenic activities, the lake ecosystem as well as fish and attributes of the fisheries sector are severely degraded. Fish species in Lake Tana are suffering due to illegal fishing, damming, habitat/breeding ground degradation, wastewater disposal, introduction of exotic species, and lack of implementing fisheries regulations. Currently, more than 98% of fishers in Lake Tana are using the most destructive monofilament. Indeed, dams, irrigation schemes and hydropower are constructed in response to the emerging development need only. Mitigation techniques such as construction of fish ladders for the migratory fishes are the most forgotten. In addition, water resource developers are likely unaware of both the importance of the fisheries and the impact of dam construction on fish. As a result, the biodiversity issue is often missed. Besides, Lake Tana wetlands, which play vital role to sustain biodiversity, are not wisely utilised in the sense of the Ramsar Convention’s definition. Wetlands are considered as unhealthy and hence wetland conversion for the purpose of recession agriculture is still seen as advanced mode of development. As a result, many wetlands in the lake watershed are shrinking drastically over time and Cyprus papyrus, one of the characteristic features of Lake Tana, has dramatically declined in its distribution with some local extinction. Furthermore, the recently introduced water hyacinth (Eichhornia crassipes) is creating immense problems on the lake ecosystem. Moreover, currently, 1.56 million tons of sediment have deposited into the lake each year and wastes from the industries and residents are directly discharged into the lake without treatment. Recently, sign of eutrophication is revealed in Lake Tana and most coarsely, the incidence of cyanobacteria genus Microcystis was reported from the Bahir Dar Gulf of Lake Tana. Thus, the direct dependency of the communities on the lake water for drinking as well as to wash their body and clothes and its fisheries make the problem worst. Indeed, since it is home to many endemic migratory fish, such kind of unregulated developmental activities could be detrimental to their stocks. This can be best illustrated by the drastic stock reduction (>75% in biomass) of the world unique Labeobarbus species. So, unless proper management is put in place, the anthropogenic impacts can jeopardize the aquatic ecosystems. Therefore, in order to sustainably use the aquatic resources and fulfil the needs of the local people, every developmental activity and resource utilization should be carried out adhering to the available policies.

Keywords: anthropogenic impacts, dams, endemic fish, wetland degradation

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