Search the digital library catalog

Abstract: This article presents the development and implementation of an IoT-enabled, off-grid solar power supply prototype designed to power a range of electrical devices. The developed system comprises a Photovoltaic panel, a Maximum Power Point Tracking (MPPT) charger, a 2.5 kWh/24 V high-performance LiFePO4 battery bank with a Battery Management System, an embedded controller with IoT connectivity, and DC/DC and DC/AC converters. The PV panel serves as the primary energy source, with the MPPT controller optimizing battery charging, while the DC/DC and DC/AC converters supply power to the connected electrical devices. The article includes a case study of a developed platform for powering an information and advertising system. The system features a predictive energy management algorithm, which optimizes the appliance operation based on daily solar irradiance forecasts and real-time battery State-of-Charge monitoring. The IoT-enabled controller obtains solar irradiance forecasts from an online meteorological service via API calls and uses these data to estimate energy availability for the next day. Using this prediction, the system schedules and prioritizes the operations of connected electrical devices dynamically to optimize the performance and prevent critical battery discharge. The IoT-based controller is equipped with both Wi-Fi and an LTE modem, enabling communication with online services via wireless or cellular networks.
Keywords: energy consumption control, forecasted solar irradiation, power management, off-grid power supply, photovoltaic, solar, IoT, LTE, Wi-Fi, ESP32
Published in DKUM: 14.11.2025; Views: 0; Downloads: 2
Full text (5,16 MB)

Abstract: The issue addressed in this paper concerns the erosion of trust within supply chains, as reported by key industry stakeholders. In this context, automotive component buyers frequently rely on single-source suppliers, thereby intensifying competitive pressures on component manufacturers. Consequently, automotive component suppliers must seek to strengthen supplier relationships to enhance trust. Given the limited opportunities for differentiation, automotive component suppliers increasingly pursue alternative strategies to ensure their long-term sustainability, with a particular emphasis on value-driven supplier relationships founded on trust. Existing literature suggests that optimised supplier relationships contribute to trust-building. This study employs a quantitative approach, utilising path analysis to identify the relationship value construct exhibiting the strongest correlation with trust. The findings indicate a significant correlation between product quality and delivery, suggesting that the timely and accurate delivery of products is the most critical factor in fostering trust between buyers and suppliers. Additionally, the analysis reveals that the most statistically significant aspect of relationship value is product quality and delivery. The paper concludes with theoretical and managerial recommendations, including the implementation of a relational governance strategy within automotive supply chains to strengthen trust and enhance long-term sustainability.
Keywords: supply chain relationships, buyer-seller relationships, South African automotive industry, relationship governance
Published in DKUM: 28.10.2025; Views: 0; Downloads: 3
Full text (482,84 KB)
This document has many files! More...

Abstract: The article examines consumer protection in the electricity market, focusing on vulnerable customers and the right to emergency supply. At EU level, it outlines the development from the energy legislative packages to Directive (EU) 2019/944, which strengthens consumer rights and requires Member States to define and protect vulnerable groups. In Slovenia, these issues are regulated by Article 33 of the Electricity Supply Act (ZOEE), implemented through the System Operating Instructions (SONDSEE) and the Energy Agency’s act on criteria for ensuring emergency supply. The article applies normative and comparative legal analysis, reviews the Energy Agency’s Annual Reports, and analyzes case law. The findings reveal a gap between regulation and practice, as only one request for emergency supply was approved in Slovenia, in 2019. It proposes clearer criteria, simpler procedures, and more effective consumer information, particularly for vulnerable groups, to ensure the right to emergency supply is realized in practice.
Keywords: consumer protection, vulnerable customers, emergency supply, electricity market, ZOEE, Directive (EU) 2019/944, energy poverty, Energy Agency
Published in DKUM: 01.10.2025; Views: 0; Downloads: 6
Link to file

Abstract: Energy is an essential component of our daily lives. Despite the expanded use of new and renewable energy sources, oil and gas remain the primary sources of energy. Recently, oil and gas sources have become more vulnerable due to their limited and uncertain availability, as well as geopolitical issues that threaten the security of their supply chains. As a result, securing energy sources in general and oil and gas in particular at reasonable prices and reliable supplies has become a major global concern. As a result, the establishment and operation of energy hubs along energy transit routes between producing and consuming countries is crucial for the security and sustainability of the energy supply. These energy hubs can facilitate the trade and exchange of energy by offering logistics services such as transportation, storage, processing, and distribution. This means that establishing and operating such energy hubs necessitates some logistics requirements. However, previous studies did not tackle the logistics requirements for establishing and operating energy hubs in a single, comprehensive framework. Accordingly, the purpose of this study is to address the logistics requirements of energy hubs, with a focus on oil and gas, and to develop a comprehensive framework for establishing and operating GLEH through conducting an empirical study on the Egyptian oil and gas industry. The study was carried out through seven sequential phases. The study conducted a systematic review of the previous literature using the PRISMA flow diagram and visual bibliometric analysis via VOSviewer software to identify the main research gap and develop an integrated theoretical framework for creating and operating a GLEH. The study then adopted mixed research methods to reap the benefits of both qualitative and quantitative methods. The qualitative technique was used to convert the theoretical framework into a practical framework by conducting semi-structured interviews with key stakeholders. The quantitative method was applied to examine the relationships between the variables and validate the study’s hypotheses in the Egyptian context through a survey. The study set out an applied framework to help establish and operate GLEHs that can improve the security of energy supplies. It also highlighted the key challenges that might face the establishment and operation of GLEHs and suggested strategies to deal with them. The study would contribute to science by developing a unique and comprehensive framework for establishing and operating GLEHs, considering both theoretical and empirical aspects. At a practical level, the proposed framework can help improve the global energy supply chain and its sustainability, especially for oil and gas. It can also be used as a model by other countries and regions to establish and operate logistics hubs for energy and other sectors. Furthermore, the framework can be used in further research to develop the performance of energy hubs.
Keywords: Energy supply chain, energy sustainability and security, global logistics energy hub, oil and gas, Egypt
Published in DKUM: 27.08.2025; Views: 0; Downloads: 4
Full text (9,35 MB)

Abstract: Our study explored the relationships between supply chain (SC) members and theirlocal and global stakeholders in achieving sustainability goals based on requisite ho-listic analysis and system dynamics modeling, which goes beyond the previous at-tempts to improve SC sustainability. In this research, we first developed a model thataddresses the basic holistic treatment of SC sustainability; in a second model of sus-tainable SC (SSC), we then considered requisite holistic interactions among its stake-holders. We used the theory-based viable system model to diagnose the proposedholistic model of SSC. The results show that especially the low-tier SC members re-quire supporting frameworks to develop and maintain the capacity for sustainable in-teractions with nature and society. These supportive frameworks should be providedby the regulatory bodies, society, and nature representatives to surpass the limitedSC profit-oriented incentives and structures. The implications of the proposed modelsare aimed at developing supportive SC sustainable policies and improving the capaci-ties of SC members to coexist with local social and natural environments. Regulators,society, and the natural environment representatives can apply the proposed modelsto establish new policies for sustainable interactions between SC members and othersocietal stakeholders.
Keywords: requisite holism, stakeholders, supply chain, sustainability, systems thinking, viable systems model
Published in DKUM: 01.07.2025; Views: 0; Downloads: 3
Full text (1,61 MB)
This document has many files! More...