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En este documento, proponemos una solución de eficiencia energética para implementar la codificación de red (NC) en redes inalámbricas basada en el estándar IEEE 802.11. El mecanismo propuesto, llamado GreenCode, permite a los nodos realizar el ciclo de trabajo cambiando a un estado de baja potencia (suspensión) cuando escuchan transmisiones de paquetes codificados que no proporcionarán ninguna información nueva para ellos. Para facilitar la operación de suspensión, las transmisiones bidireccionales que involucran paquetes codificados y no codificados entre pares de nodos remitente-receptor se integran en la operación de GreenCode. Tanto los resultados analíticos como de simulación presentados en este documento muestran la alta eficiencia energética de GreenCode con ganancias de hasta el 360% en comparación con los mecanismos existentes basados en el Estándar IEEE 802.11. Dans cet article, nous proposons une solution écoénergétique pour la mise en œuvre du codage de réseau (NC) dans les réseaux sans fil basée sur la norme IEEE 802.11. Le mécanisme proposé, appelé GreenCode, permet aux nœuds de fonctionner en passant à un état de faible puissance (veille) lorsqu'ils entendent des transmissions de paquets codés qui ne leur fourniront aucune nouvelle information. Pour faciliter le fonctionnement en veille, des transmissions bidirectionnelles impliquant à la fois des paquets codés et non codés entre des paires de nœuds expéditeurs-récepteurs sont intégrées dans le fonctionnement de GreenCode. Les résultats d'analyse et de simulation présentés dans cet article montrent l'efficacité énergétique élevée de GreenCode avec des gains allant jusqu'à 360% par rapport aux mécanismes existants basés sur la norme IEEE 802.11. In this paper, we propose an energy-efficient solution for implementing Network Coding (NC) in wireless networks based on the IEEE 802.11 Standard. The proposed mechanism, called GreenCode, allows nodes to duty cycle by switching to a low-power (sleep) state when they overhear coded packet transmissions that will not provide any new information for them. To facilitate the sleep operation, bidirectional transmissions involving both coded and non-coded packets between pairs of sender-receiver nodes are integrated into the operation of GreenCode. Both analytical and simulation results presented in this paper show the high energy efficiency of GreenCode with gains of up to 360% when compared to the existing mechanisms based on the IEEE 802.11 Standard. في هذه الورقة، نقترح حلاً موفرًا للطاقة لتنفيذ ترميز الشبكة (NC) في الشبكات اللاسلكية بناءً على معيار IEEE 802.11. تسمح الآلية المقترحة، المسماة GreenCode، للعقد بدورة العمل عن طريق التبديل إلى حالة منخفضة الطاقة (السكون) عندما تسمع عمليات إرسال الحزم المشفرة التي لن توفر أي معلومات جديدة لها. لتسهيل عملية السكون، يتم دمج عمليات الإرسال ثنائية الاتجاه التي تنطوي على كل من الحزم المشفرة وغير المشفرة بين أزواج من عقد المرسل والمستقبل في تشغيل GreenCode. تُظهر كل من النتائج التحليلية والمحاكاة المقدمة في هذه الورقة كفاءة الطاقة العالية للـ GreenCode مع مكاسب تصل إلى 360 ٪ بالمقارنة مع الآليات الحالية القائمة على معيار IEEE 802.11.

The primary goal of this paper is to investigate the most cost-effective decommissioning and refurbishment investment decision for existing gas networks. An optimization model is developed and tested on a real test bed in an Austrian federal state. The analysis is performed from the network operator’s perspective and depicts different network decommissioning or refurbishment options under the decision of supplying or not supplying available gas demands. Whether or not there is ensured supply, we find that smaller gas networks (in terms of pipeline capacity and network length) are needed in the future. Analyzed shadow prices indicate that a balance/trade-off between the cost-optimal gas network design with and without ensured supply could lead to a robust and economically competitive future for downsized gas networks. The results demonstrate that it is necessary to socialize network operators’ costs among the remaining consumers connected to the network in the future. This adds a cost component to consumers, which needs to be considered when determining the profitability of sustainable alternatives to natural gas.

La energía solar térmica para procesos industriales (SHIP por sus siglas en inglés) está adquiriendo una relevancia creciente como una de las formas de satisfacer la demanda de energía térmica necesaria para la industria. Esto conlleva un doble beneficio: en primer lugar, al utilizar una fuente de energía renovable, se reduce el consumo de combustibles fósiles, así como las emisiones de contaminantes y gases de efecto invernadero a la atmósfera; en segundo lugar, el calor para los procesos industriales se postula como un nicho de mercado distinto para la tecnología solar, lo que puede conducir a una disminución en el coste de los colectores solares mediante economías de escala en la fabricación y avances en la curva de aprendizaje en la implementación. Este trabajo presenta el proyecto ASTEP (Application of Solar Thermal Energy to Processes), que desarrolla un concepto innovador de SHIP, así como los avances actuales, recopilando los resultados del proyecto hasta la fecha.

Floods are among the most devastating disasters in terms of socio-economics and casualties. However, these natural disasters can be managed and their effects can be minimized by flood modeling performed before the occurrence of a flood. In this study, flood modeling was developed for the Göksu River Basin, Mersin, Türkiye. Flood hazard and risk maps were prepared by using GIS, HEC-RAS, and HEC-HMS. In hydraulic modeling, Manning’s n values were obtained from 2018 CORINE data, return period flow rates (Q25, Q50, Q100, Q500) were obtained from HEC-HMS, and the application was carried out on a 5 m resolution digital surface model. In the study area, the water depths could reach up to 10 m, and water speeds were approximately 0.7 m/s. Considering these values and the fact that the study area is an urban area, hazard maps were obtained according to the UK Department for Environment, Food and Rural Affairs (DEFRA) method. The results indicated that possible flood flow rates from Q25 to Q500, from 1191.7 m3/s to 1888.3 m3/s, were detected in the study area with HEC-HMS. Flooding also occurred under conditions of the Q25 flow rate (from 4288 km2 to 5767 km2), and the impacted areas were classified as extremely risky by the DEFRA method.

Monthly Indian energy and activity data used for estimating India's monthly fossil CO2 emissions. Data are collated from a large number of source files, all in the public domain, and documented in the journal article of the same title. NOTE: These data are being regularly updated here: https://robbieandrew.github.io/india/.

Decarbonisation of the iron and steel industry would require the use of innovative low-carbon production technologies. Use of 100% hydrogen in a shaft furnace (SF) to reduce iron ore has the potential to reduce emissions from iron and steel production significantly. In this work, results from the techno-economic assessment of a H2-SF connected to an electric arc furnace(EAF) for steel production are presented under two scenarios. In the first scenario H2 is produced from molten metal methane pyrolysis in an electrically heated liquid metal bubble column reactor. Grid connected low-temperature alkaline electrolyser was cosnidered for H2 production in the second scenario. In both cases, 59.25 kgH2 was required for the production of one ton of liquid steel (tls). The specific energy consumption (SEC) for the methane pyrolysis based system was found to be 5.16 MWh/tls. The system used 1.51 MWh/tls of electricity, and required 263 kg/tls of methane, corresponding to an energy consumption of 3.65 MWh/tls. The water electrolysis based system consumed 3.96 MWh/tls of electricity, at an electrolyser efficiency of 50 KWh/kgH2. Both systems have direct emissions of 129.4 kgCO2/tls. The indirect emissions are dependent on the source of natural gas, pellet making process and the grid-emission factor. Indirect emissions for the electrolysis based system could be negligible, if the electricity is generated from renewable energy sources. The levellized cost of production(LCOP) was found to be $631, and $669 respectively at a discount rate of 8%, for a plant-life of 20 years. The LCOP of a natural gas reforming based direct reduction steelmaking plant of operating under similar conditions was found to be $414. Uncertainty analysis was conducted for the NPV and IRR values. The Python scripts used for the calculations can be accessed at 10.5281/zenodo.4504841 {"references": ["10.5281/zenodo.4504841"]}

An increasing penetration of EVs and their charging impose challenges to the energy grid stability. As a consequence, an optimal management of EV charging in parking lots becomes essential. This work presents an approach of a cooperative control of charging stations based on a stochastic optimization model for the energy management of a group of charging stations. Uncertainties regarding the number of charging EVs at each time step were modelled using a Markovian process, while the probability mass function was generated using a Monte Carlo simulation. Furthermore, the concept prioritizes the exploitation of local renewable resources and energy storage for EV charging. The stochastic optimization model was integrated into our own developed Stochastic Optimization Software Framework (SOFW), which deploys the application as Model Predictive Control (MPC) in the real-time scenario using dynamic programming. The cooperative control of charging stations presented in this work was evaluated succesfully with a variety of EV driving scenarios. The approach will be validated in the future on the field in a car park of a DSO company including renewable generation and energy storage system.