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Papanikolaou, Apostolos (National Technical University of Athens) | Zaraphonitis, George (National Technical University of Athens) | Jokinen, Markus (Elomatik Oy) | Aubert, Adrien (Bureau Veritas) | Harries, Stephan (Friendship Systems AG) | Marzi, Jochen (Hamburger Schiffbau-Versuchsanstalt GmbH) | Mermiris, George (Tritec Marine Limited) | Gunawan, Rachmat (Bureau Veritas)
The pattern of seaborne trade and goods transportation is changing and ships need to adapt to changes of customer and market requirements, cargo volumes, and new legislation for the safety of ships and nowadays, even more, to the strict regulatory requirements for the protection of the environment. Responding to the urgent needs for substantial reduction of GHG (Green House gas) emissions from marine operations in line with the ambitious targets set by the International Maritime Organisation and the European Commission, a series of research and development works were initiated in the maritime sector for the ships designed and built today and be operating in the next decades to meet future environmental requirements. Responding to these needs, the recently completed Horizon 2020 European Research project – HOLISHIP – Holistic Optimisation of Ship Design and Operation for Life Cycle (2016-2020) has developed suitable tools and software platforms, as necessary for the creation of innovative design solutions meeting the set low emission strategic objectives. The present paper is presenting the HOLISHIP, multi-objective optimisation approach to green shipping and demonstrates a subset of its functionality by two green design RoPAX case studies.
Xu, Zhiguo (National Marine Environmental Forecasting Center, Ministry of Natural Resources. Beijing) | Wang, Zongchen (National Marine Environmental Forecasting Center, Ministry of Natural Resources. Beijing) | Shi, Jianyu (National Marine Environmental Forecasting Center, Ministry of Natural Resources. Beijing) | Li, Hongwei (National Marine Environmental Forecasting Center, Ministry of Natural Resources. Beijing)
ABSTRACT Multiple-point source solution of 2020 Samos Mw7.0 earthquake in Greek was inverted using iterative deconvolution method from near field seismic records. The retrieving results have revealed that Samos Mw7.0 earthquake consisted of at least two subevent with similar normal fault-typing, the smaller subevent corresponds to ~3 s rupture time close to mainshock epicenter, the larger one has its position approximately 25 km west of the original rupture point with 8 s later moment release. We inferred that Samos earthquake occurred on a normal fault along the nearly EW trending, and two subevents successively ruptured separated by ~5 s. Furthermore, numerical simulation of the tsunami generated by Samos normal faulting earthquake was conducted from the uniform slip source model, indicating the Samos earthquake occurred as subsidence of normal fault hanging wall, and led to a large sudden coseismic vertical deformation surrounding the focal region, thus displacing the overlying water and produced a small scale local tsunami. INTRODUCTION A massive Mw = 7.0 earthquake that occurred ~10 km to the north and offshore of Samos Island, Greece (37.897°N 26.784°E) On 30 October 2020 11:51 UTC, at a shallow depth of ~21 km. This earthquake caused extensive damage on its surrounding areas, resulted in the collapse of buildings, numerous fatalities, and missing people, at least ~117 people were killed by earthquake. Most notably, the mainshock also triggered a powerful local tsunami that flooded into the island of Samos Island, Greece and the Aegean coast of the Izmir region, Turkey, and caused severely damage to building and structure, one person killed by drowning. After the Samos mainshock, the researchers from various earthquake agencies have made great progresses in understand this earthquake. The analysis of the mainshock and aftershock sequence reveals that it occurred on a nearly EW striking dip-slip normal fault located off the northern shore of Samos Island (Onder-Cetin et al., 2020; Papadimitriou et al. 2020). The distance between the USGS's initial epicenter and GCMT's centroid location is ~19 km (Fig. 1), indicating the the seismogenic zone is not considered to be single point source, the main rupture slip is located to west of the epicenter. The two major slip patches derived from the regional finite fault modeling. Hence, we employed the multiple-point source modeling to explore the focal mechanism characteristics, and further unveiling the temporal and spatial characteristics of the rupture.
Nowadays, geophysical prospecting is routinely used to detect, map or image buried ancient remnants and ancient It was recognized from the commencement of the structures. The principle is that the concealed antiquities "archaeological prospection", and stated emphatically in the pose a discernible contrast in physical properties with fundamental paper of Schollar et al (1986), that the survey respect to the burial environment. Therefore, they create outcomes should be visualized in a form showing the ground anomalies at the natural or manmade geophysical fields. The view of the buried antiquities. I.e., the mapped geophysical recorded anomalies, after appropriate processing and fields have to be transformed in an image resembling more visualization, usually yield images looking like the ground or less the ground view of the subsurface bodies which have view of the antiquities.
Ilias Gavrielatos Ilias Gavrielatos is a Graduate Research and Teaching Assistant currently pursuing a PhD in Petroleum Engineering at The University of Tulsa (TU), Oklahoma, USA. His research interests include enhanced oil recovery (EOR) processes, multi-phase flow in porous media and pipes, flow assurance (oil/water emulsions), and renewable energy technologies. Gavrielatos holds advanced degrees in Chemical Engineering from the University of Patras in Greece, as well as an MS in Petroleum Engineering from TU. Gavrielatos is a member of SPE and ASME. Gavrielatos holds advanced degrees in Chemical Engineering from the University of Patras in Greece, as well as an MS in Petroleum Engineering from TU. Gavrielatos is a member of SPE and ASME.
Loukogeorgaki, Eva (Aristotle University of Thessaloniki) | Michailides, Constantine (Cyprus University of Technology) | Lavidas, George (Delft University of Technology) | Chatjigeorgiou, Ioannis K. (National Technical University of Athens)
Abstract In this paper, we determine optimum layouts of a cluster of oblate spheroidal heaving point absorbers in front of a wall, that maximize the annual averaged power absorbed by the cluster, while satisfying specific spatial constraints. An iterative optimization process is developed by coupling a hydrodynamic model with a genetic algorithms solver. Optimization is performed for three near-shore sites in the Aegean Sea, Greece. Optimum layouts are obtained considering part of or the whole wall length, available for the PAs' sitting. The effect of the incident wave direction on the optimum layouts' formation and the absorbed power is also assessed. Finally, the dependence of the maximized absorbed power upon the deployment site is illustrated. Introduction Contemporary technological advances seek the efficient exploitation of the vast wave energy potential. Accordingly, the technology of Wave Energy Converters (WECs) is continuously being developed during the past years, aiming at delivering commercially competitive solutions that maximize efficiency, ensure survivability, reduce costs and minimize environmental impacts. Heaving type Point Absorbers (PAs) correspond to one of the most technologically advanced type of WECs, characterized by the "one-mode" operation simplicity. Some characteristic examples of PAs are the Wavestar (Hansen et al., 2013) and the Seabased AB (Chatzigiannakou et al., 2017). In order to absorb an adequate amount of power and, thus, contribute to the reduction of the high Levelized Cost of Electricity (LCoE), representing currently one of the main drawbacks of WECs (Rusu and Onea, 2018), multiple PAs in the form of clusters (arrays) can be deployed (e.g., Stratigaki et al., 2014; Balitsky et al., 2018). Alternatively to offshore marine areas, PAs clusters can be also deployed at near-shore locations. In those cases, coastal structures, such as vertical (wall-type) breakwaters, occupying a large ocean space, may exist, while the relevant asset owners and operators may seek for additional integrated alternative uses of the existing marine facilities. Within this context, clusters of PAs can be deployed in the seaward side of wall-type breakwaters facilitating the exploitation of both the incident waves and the waves reflected from the wall. This idea falls within the wider approach of integrating WEC technologies with coastal structures (e.g., Zhao et al., 2019; Rosa-Santos et al., 2019; Vicinanza et al., 2012; Michailides and Angelides, 2015) and it can support the realization of cost-efficient solutions through costs sharing.
Abstract In the present study a Froude scale model of an offshore wind turbine (OWT) was designed, based on the NREL 5MW-OC3-Hywind floating OWT concept minor modifications, and its dynamic response was experimentally tested under varying wave conditions. Spectral analyses of the measurements were carried out to investigate the dynamic behavior of the wind turbine including the calculation of the Response Amplitude Operator (RAO) for the critical motions of the OWT. Results demonstrate that the critical motions of the OWT under incident regular and irregular waves are surge and pitch. For regular waves the critical frequency of the OWT motions coincides with the frequency of the waves, while for irregular waves the critical frequency is the free oscillation (natural) frequency of the respective OWT motion. Introduction In the last years, the increased demand for electricity, in combination with the commitments to significantly reduce CO2 emissions at the same time, makes the need of sustainable energy extremely imperative. Among the different sources for renewable energy production, blue energy is becoming more and more popular regarding energy production from wind, waves, and tidal potential. The first to visualize large scale floating offshore wind turbines (OWTs) was Heronemus in 1972 (Tomasicchio et al., 2018). However, until nowadays the dynamic response of such structures, under the combined attack of wind and waves, remains a multiparametric and challenging topic that still attracts the interest of researchers worldwide. Greece, with its exceptional wind potential and vast marine space, should pursue the installation and use of floating OWTs so that it will both meet its energy needs and effectively deal with potential shortfalls of wind turbines on land. The implementation of such systems should be planned according to the winds blowing in Greece as well as by the relatively small depth of its coastal seas. To date, mainly the high cost associated with such ventures has proved to be a stumbling block since the existing floating OWTs are extremely sizeable for the environmental conditions not only of Greece but in the Mediterranean in general. Therefore, designing a smaller and more economical floating OWT, adapted to the conditions in Greece, as well as the assessment of its hydrodynamic behavior has been deemed appropriate.
This month I want to discuss what has recently become a very popular topic among both industry and academia--developing our talent. To weather the big crew change successfully, much of the solution surely involves how we instruct petroleum engineering students, how we train young professionals once they join the industry, and how we continually educate experienced engineers to ensure a sufficiently competent workforce. As the recent SBC O&G HR Benchmark Study (Schlumberger 2012) and the 2013 SPE Forum on Engineering Education (Chase 2013) both concluded, the issue isn't just about the numbers (people shortage), it is about the skills (talent gap). The way in which we educate at the university level is under revolutionary change in all disciplines, including the science, technology, engineering, and math subjects that feed our industry. Considering that the brick-and-mortar, lecturer-student model has been substantially the same since ancient Greece, it's probably time for change.