An experimental and CFD study of the extreme waves impact on OC3-Hywind Spar Floating offshore wind turbine

The study presents a combined wave tank experiment and Computational Fluid Dynamics(CFD) study on the OC3-Hywind Spar Floating [1] offshore wind turbine under extreme wave conditions. Focused wave is adopted in the present study as one of the effective ways to model the extreme wave. The main objectives of this study are to demonstrate how the focused waves could represent the extreme waves and the difference of focused waves approach and other wave types to model extreme waves, i.e., irregular waves. The experimental tank test was carried out with a 1/74 scale model both in irregular and focused wave conditions in Kelvin Hydrodynamics Laboratory at the University of Strathclyde. The irregular waves are designed by using identical wave spectrum with focused waves in the wave tank, and it will be helpful to determine the viability of using different wave types to represent high amplitude waves. The study provides a comparison of the dynamic responses, motion RAOs of the floater between focused waves and irregular waves. In addition, an in-house CFD code[2][3][4] based on an open-source CFD framework OpenFOAM [5] is adopted to simulate the fluid flow around the Spar-FOWT in a numerical wave tank under regular and focused wave conditions. Firstly, for code validation, the dynamic response of the Spar-FOWT is simulated under regular waves and the results are compared with the existing research [6]. Next, the focused wave with the identical wave spectrum provided by the experimental test is generated in our numerical wave tank without the floating structure. After the validation of the focused wave generation, the wave-structure interaction and the dynamic response of the Spar-FOWT is investigated under the focused wave. The results show good agreement with the tank test which demonstrates the capacity and the fidelity of our CFD tools

Towards practical guidelines for conversion from fixed to reconfigurable manufacturing automation systems

It is generally considered that economic feasibility of a reconfigurable manufacturing system is only attainable if the system is defined to be reconfigurable at the outset of its design. In this work we consider the potential exception to this perception, in the context of a common industrial scenario where a specialized and expensive manufacturing machine or system will otherwise be rendered useless due to loss of business of the particular product being manufactured. Specific guidelines to convert from a fixed to a reconfigurable system are proposed, and evaluated through a case study. It is shown that under certain conditions, reconfigurable manufacturing systems may be economically feasible even if they are developed through the modification of pre-existing dedicated systems.peer-reviewe

Towards practical guidelines for conversion from a fixed to a reconfigurable manufacturing automation system

It is generally considered to be a key requirement in the development of reconfigurable manufacturing systems, that economic feasibility is only attainable if the system is defined to be reconfigurable at the outset of its design. In this work we consider the potential exception to this requirement, in the context of a common industrial scenario where a specialized and expensive manufacturing machine or system will otherwise be rendered useless due to loss of business of the particular product being manufactured. Specific guidelines to convert from a fixed to a reconfigurable system are proposed, and evaluated through a case study.peer-reviewe

Skills of the user-relevant ocean indicators

This document demonstrates the capability of seasonal forecasting systems to predict observable and user-relevant ocean climate indicators

The mediterranean sea we want

open58siThis paper presents major gaps and challenges for implementing the UN Decade of Ocean Science for Sustainable Development (2021-2030) in the Mediterranean region. The authors make recommendations on the scientific knowledge needs and co-design actions identified during two consultations, part of the Decade preparatory-phase, framing them in the Mediterranean Sea’s unique environmental and socio-economic perspectives. According to the ‘Mediterranean State of the Environment and Development Report 2020’ by the United Nations Environment Programme Mediterranean Action Plan and despite notable progress, the Mediterranean region is not on track to achieve and fully implement the Sustainable Development Goals of Agenda 2030. Key factors are the cumulative effect of multiple human-induced pressures that threaten the ecosystem resources and services in the global change scenario. The basin, identified as a climate change vulnerability hotspot, is exposed to pollution and rising impacts of climate change. This affects mainly the coastal zones, at increasing risk of extreme events and their negative effects of unsustainable management of key economic assets. Transitioning to a sustainable blue economy is the key for the marine environment’s health and the nourishment of future generations. This challenging context, offering the opportunity of enhancing the knowledge to define science-based measures as well as narrowing the gaps between the Northen and Southern shores, calls for a joint (re)action. The paper reviews the state of the art of Mediterranean Sea science knowledge, sets of trends, capacity development needs, specific challenges, and recommendations for each Decade’s societal outcome. In the conclusions, the proposal for a Mediterranean regional programme in the framework of the Ocean Decade is addressed. The core objective relies on integrating and improving the existing ocean-knowledge, Ocean Literacy, and ocean observing capacities building on international cooperation to reach the “Mediterranean Sea that we want”.openCappelletto M.; Santoleri R.; Evangelista L.; Galgani F.; Garces E.; Giorgetti A.; Fava F.; Herut B.; Hilmi K.; Kholeif S.; Lorito S.; Sammari C.; Lianos M.C.; Celussi M.; D'alelio D.; Francocci F.; Giorgi G.; Canu D.M.; Organelli E.; Pomaro A.; Sannino G.; Segou M.; Simoncelli S.; Babeyko A.; Barbanti A.; Chang-Seng D.; Cardin V.; Casotti R.; Drago A.; Asmi S.E.; Eparkhina D.; Fichaut M.; Hema T.; Procaccini G.; Santoro F.; Scoullos M.; Solidoro C.; Trincardi F.; Tunesi L.; Umgiesser G.; Zingone A.; Ballerini T.; Chaffai A.; Coppini G.; Gruber S.; Knezevic J.; Leone G.; Penca J.; Pinardi N.; Petihakis G.; Rio M.-H.; Said M.; Siokouros Z.; Srour A.; Snoussi M.; Tintore J.; Vassilopoulou V.; Zavatarelli M.Cappelletto M.; Santoleri R.; Evangelista L.; Galgani F.; Garces E.; Giorgetti A.; Fava F.; Herut B.; Hilmi K.; Kholeif S.; Lorito S.; Sammari C.; Lianos M.C.; Celussi M.; D'alelio D.; Francocci F.; Giorgi G.; Canu D.M.; Organelli E.; Pomaro A.; Sannino G.; Segou M.; Simoncelli S.; Babeyko A.; Barbanti A.; Chang-Seng D.; Cardin V.; Casotti R.; Drago A.; Asmi S.E.; Eparkhina D.; Fichaut M.; Hema T.; Procaccini G.; Santoro F.; Scoullos M.; Solidoro C.; Trincardi F.; Tunesi L.; Umgiesser G.; Zingone A.; Ballerini T.; Chaffai A.; Coppini G.; Gruber S.; Knezevic J.; Leone G.; Penca J.; Pinardi N.; Petihakis G.; Rio M.-H.; Said M.; Siokouros Z.; Srour A.; Snoussi M.; Tintore J.; Vassilopoulou V.; Zavatarelli M

Myocardial energy depletion and dynamic systolic dysfunction in hypertrophic cardiomyopathy

Evidence indicates that anatomical and physiological phenotypes of hypertrophic cardiomyopathy (HCM) stem from genetically mediated, inefficient cardiomyocyte energy utilization, and subsequent cellular energy depletion. However, HCM often presents clinically with normal left ventricular (LV) systolic function or hyperkinesia. If energy inefficiency is a feature of HCM, why is it not manifest as resting LV systolic dysfunction? In this Perspectives article, we focus on an idiosyncratic form of reversible systolic dysfunction provoked by LV obstruction that we have previously termed the 'lobster claw abnormality' — a mid-systolic drop in LV Doppler ejection velocities. In obstructive HCM, this drop explains the mid-systolic closure of the aortic valve, the bifid aortic pressure trace, and why patients cannot increase stroke volume with exercise. This phenomenon is characteristic of a broader phenomenon in HCM that we have termed dynamic systolic dysfunction. It underlies the development of apical aneurysms, and rare occurrence of cardiogenic shock after obstruction. We posit that dynamic systolic dysfunction is a manifestation of inefficient cardiomyocyte energy utilization. Systolic dysfunction is clinically inapparent at rest; however, it becomes overt through the mechanism of afterload mismatch when LV outflow obstruction is imposed. Energetic insufficiency is also present in nonobstructive HCM. This paradigm might suggest novel therapies. Other pathways that might be central to HCM, such as myofilament Ca2+ hypersensitivity, and enhanced late Na+ current, are discussed

Copernicus Ocean State Report, issue 6

The 6th issue of the Copernicus OSR incorporates a large range of topics for the blue, white and green ocean for all European regional seas, and the global ocean over 1993–2020 with a special focus on 2020