1,720,985 research outputs found
Methanol fuelled hybrid propulsion system for a charter yacht
No full textThe maritime sector is increasingly leaning towards making large and small vessels eco-sustainable. The pleasure craft and yacht sectors are particularly sensitive to environmental issues. This work presents a concept design of a charter yacht able to operate in green-mode by means of an Energy Storage System and High-Temperature PEM Fuel Cell fuelled by methanol.Once the main components were chosen and sized based on the design requirements, a simplified mission profile was parameterized in order to discretize which mission profile is allowed in green mode with the propulsion plant designed. Different sizes of the propulsion system (FC power and batteries capacity) were analysed in terms of performance and overall dimension to provide interesting results for industrial applications
A Methanol Fueled Marine Engine Simulator for Fast Craft Applications
No full textThe paper presents a thermodynamic simulator of a marine four-stroke medium speed engine, fueled by methanol. The study stems from the current lack of information on methanol marine engines, whereas there is a growing interest in this type of alternative fuel, also in the maritime field. The numerical model, developed in Matlab©-Simulink© language and structured in a modular form, is derived from a natural gas marine engine simulator, developed by the authors and already described and validated in a previous research study. In the methanol engine model, for the in cylinder phenomena calculation, the zero dimensional actual cycle approach is adopted, while the turbocharger compressor and turbine are simulated by their performance maps. After a short description of the original natural gas simulator, the paper reports the variations introduced for adapting the engine model to the methanol fuel mode. The obtained outcomes are compared with data referring to a dual fuel natural gas engine, available in the literature. This comparison, between the simulated results of the two fuel modes of the engine, aims at highlighting the differences in efficiency and carbon dioxide emissions, in order to improve the environmental impact of the medium and high-speed vessels
Simulation Analysis of a Methanol Fueled Marine Engine for the Ship Decarbonization Assessment
Full text linkMethanol as marine fuel represents one of the most cost-effective and practical solutions towards low-carbon shipping. Methanol fueled internal combustion engines have a high level of technological readiness and are already available on the market; however, technical data in terms of fuel consumption and emissions are not yet easily accessible. For this reason, the present study deals with the simulation of a virtual spark-ignition methanol engine, carried out in a Matlab-Simulink© R2023a environment to assess the CO2 emissions in several working conditions of a possible ship power system. The thermodynamic model of the methanol fueled engine is derived from a marine gas engine simulator, already validated by the authors in a previous work. This article presents the relevant modifications necessary to adapt the engine to the methanol fuel mode with regard to the different fuel characteristics. The simulation analysis compares the results of the virtual methanol engine with available data from a similar, existing gas engine, highlighting the differences in efficiency and carbon dioxide emissions
Comparative analysis among different alternative fuels for ship propulsion in a well-to-wake perspective
No full textThe shipping sector is required to give a significant contribution to the reduction of Green House Gas (GHG) emissions, according to the ambitious goals fixed by the International Maritime Organization (IMO). To achieve these targets, new technologies and measures are required, related to logistics, digitalization, hydrodynamics, machinery, energy, and aftertreatment. A large potential to reduce GHG emissions is offered by alternative fuels. In this perspective a Well-to-Wake (WtW) approach is due for a comprehensive analysis. The paper is focused on the evaluation of WtW CO2 equivalent emission factors for LNG, methanol, and ammonia. The extensive bibliographic research on this topic outlines the large differences occurring when considering grey or green fuel production pathways. A case study based on a cruise ship allows to compare alternative fuels produced from fossil or renewable sources, considering two typical cruise profiles. Results in terms of Carbon Intensity Indicator confirms that the WtW approach points out the great potential of alternative green fuels for GHG emissions reduction
Conflittualità e legittimazione democratica. Profili di trasformazione dello spazio politico-giuridico fra antagonismo e agonismo
No full textL’impatto del lawyering, della case-theory e dell’epistemologia sulla formazione clinico-legale. Una premessa metodologica
No full textPensare la pratica, teorizzare il diritto in azione: le cliniche legali e le nuove frontiere epistemologiche del diritto
No full textАнтропометричні характеристики юних спортсменів з бочче за спеціалізацією «Раффа»: Аналіз фізичних параметрів юних гравців національного рівня
No full textBackground. The sport of bocce, and in particular the specialty of Raffa, has seen significant competitive development in recent decades, but the scientific literature on the anthropometric characteristics of athletes, especially among young people, is still limited.
Objectives. This study aimed to analyze the physical characteristics of Raffa’s junior players at national level, focusing on anthropometric variables such as height, weight and body mass index (BMI).
Materials and methods. A sample of twenty athletes, divided into a research group consisting of ten athletes of national interest and a control group of ten non-competitive practitioners, was subjected to baseline measurements during regional events.
Results. The findings showed an average height of 170.5 cm and an average weight of 65.8 kg for the research team, with an average BMI of 22.63, indicating a condition of normal weight. However, 33.3% of the athletes in the research group were overweight or class I obese, suggesting the need for greater attention to physical preparation. The data were compared with those of the control group, which had an average height of 173.5 cm, an average weight of 74.5 kg and a BMI distribution with 50% of the athletes classified as overweight. The results were discussed in relation to the initial hypotheses and the existing literature.
Conclusions. This study offers important insights for the development of personalized training programs and for the selection of young talents, highlighting the importance of adequate physical preparation. Future prospects include deepening the analysis of the somatotype and the use of larger and more diverse samples.Історія питання. За останні десятиліття бочче як різновид спорту і, зокрема, спеціалізація «Раффа», зазнали значного конкурентноспроможного розвитку, проте наукова література щодо антропометричних характеристик спортсменів, особливо серед молоді, представлена досі обмежено.
Мета дослідження. Метою цього дослідження було проаналізувати фізичні характеристики юних раффа-гравців на національному рівні, зосередивши увагу на антропометричних показниках, як-от зріст, вага та індекс маси тіла (ІМТ).
Матеріали та методи. Задля проведення базових вимірювань під час регіональних змагань, вибірку із двадцяти спортсменів розподілено на дослідницьку групу, що складалася з десяти спортсменів національного рівня, і контрольну групу з десяти практикуючих осіб, які не брали участі у змаганнях.
Результати. За результатами дослідження середній зріст досліджуваної групи становив 170,5 см, середня вага — 65,8 кг, середній ІМТ — 22,63, що вказує на стан нормальної ваги. Однак 33,3 % спортсменів у досліджуваній групі мали надмірну вагу або ожиріння I ступеня, що свідчить про необхідність приділяти більшу увагу фізичній підготовці. Отримані дані було порівняно із показниками контрольної групи, яка мала середній зріст 173,5 см, середню вагу 74,5 кг та розподіл ІМТ, за яким 50 % спортсменів класифіковано як особи з надмірною вагою. Результати обговорено відповідно до вихідних гіпотез та наявних літературних даних.
Висновки. У цьому дослідженні представлено важливу інформацію для розробки персоналізованих тренувальних програм та відбору молодих талантів, що підкреслює важливість належної фізичної підготовки. Подальші перспективи включають поглиблення аналізу соматотипу та використання більших та різноманітніших вибірок
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