Uncertainties assessment in real-time hybrid model for ocean basin testing of a floating offshore wind turbine

ABSTARCT: This work analyses the accuracy of large-scale experimental testing procedure in ocean basin facility involving real-time hybrid model testing (ReaTHM) techniques. The analysis is based on a scaled concept for a 15MW floating offshore wind turbine (FOWT) supported by a concrete semi-submersible platform (ActiveFloat) developed within the framework of the project COREWIND. The real-time hybrid model considered includes a multi-fan system located at the aero-rotor interface, which permits to generate the aerodynamic loads, reducing the limitations typically given by scaled problems. In order to assess the uncertainties in the hardware in the loop (HIL) implementation, firstly we define the quantities of interest to be evaluated from all the possible sources liable to inaccuracy identified. Then, we quantify the systematic and random discrepancies of the selected mooring, platform and HIL parameters. Finally, we propagate the previously quantified errors, running simulations in OpenFAST under extremal and severe environmental load cases in Gran Canaria Island (Spain) site. Comparing the platform response and mooring tensions of these uncertainty propagations with the ones of the unperturbed simulation as a baseline case, we analyse the effect of each representative parameter. Thus, the reliability of the results in ocean basin testing is numerically assessed, depending on the design load case.Raúl Guanche also acknowledges financial support from the Ramon y Cajal Program (RYC-2017- 23260) of the Spanish Ministry of Science, Innovation and Universities

Surgical and Interventional Management of Complications Caused by Pancreatitis

Acute pancreatitis has a broad clinical spectrum: from mild, self-limited disease to fulminant illness resulting in multi-organ failure leading to a prolonged clinical course with up to 30% mortality in case of infected necrosis. Management of local complications such as pseudocysts and walled-off necrosis may vary from clinical observation to interventional treatment procedures. Gram negative bacteria infection may develop in up to one-third of patients with pancreatic necrosis leading to a clinical deterioration with the onset of the systemic inflammatory response syndrome and organ failure. When feasible, an interventional treatment is indicated. Percutaneous or endoscopic drainage approach are the first choices. A combination of minimally invasive techniques (step-up approach) is possible in patients with large or multiple collections. Open surgical treatment has been revised both in the timing and in the operating modalities in the last decades. Since 1990s, the surgical treatment of infected necrosis shifted to a more conservative approach. Disruption of the main pancreatic duct is present in up to 50% of patients with pancreatic fluid collections. According to the location along the Wirsung, treatment may vary from percutaneous drainage, endoscopic retrograde pancreatography with sphincterectomy or stenting to traditional surgical procedures. Patients may suffer from vascular complications in up to 23% of cases. Tissue disruption provoked by lipolytic and proteolytic enzymes, iatrogenic complications during operative procedures, splenic vein thrombosis, and pseudoaneurysms are the pathophysiological determinants of bleeding. Interventional radiology is the first line treatment and when it fails or is not possible, an urgent surgical approach should be adopted. Chylous ascites, biliary strictures and duodenal stenosis are complications that, although uncommon and transient, may have different treatment modalities from non-operative, endoscopic to open surgery

OC6 Phase II: Integration and verification of a new soil–structure interaction model for offshore wind design

This paper provides a summary of the work done within the OC6 Phase II project, which was focused on the implementation and verification of an advanced soil–structure interaction model for offshore wind system design and analysis. The soil–structure interaction model comes from the REDWIN project and uses an elastoplastic, macroelement model with kinematic hardening, which captures the stiffness and damping characteristics of offshore wind foundations more accurately than more traditional and simplified soil–structure interaction modeling approaches. Participants in the OC6 project integrated this macroelement capability to coupled aero-hydro-servo-elastic offshore wind turbine modeling tools and verified the implementation by comparing simulation results across the modeling tools for an example monopile design. The simulation results were also compared to more traditional soil–structure interaction modeling approaches like apparent fixity, coupled springs, and distributed springs models. The macroelement approach resulted in smaller overall loading in the system due to both shifts in the system frequencies and increased energy dissipation. No validation work was performed, but the macroelement approach has shown increased accuracy within the REDWIN project, resulting in decreased uncertainty in the design. For the monopile design investigated here, that implies a less conservative and thus more cost-effective offshore wind design.US Department of Energy Office of Energy Efficiency and Renewable Energy Wind Energy Technologies Office, Grant/Award Number: DE-AC36-08GO2830

Physical Model Tests on Spar Buoy for Offshore Floating Wind Energy Conversion

ABSTRACT: The present paper describes the experiences gained from the design methodology and operation of a 3D physical modelexperiment aimed to investigate the dynamic behaviour of a spar buoy floating offshore wind turbine. The physical model consists in a Froude-scaled NREL 5MW reference wind turbine (RWT) supported on the OC3-Hywind floating platform. Experimental tests have been performed at Danish Hydraulic Institute (DHI) offshore wave basin within the European Union-Hydralab+ Initiative, in April 2019. The floating wind turbine model has been subjected to a combination of regular and irregular wave attacks and different wind loads. Measurements of displacements, rotations, accelerations, forces response of the floating model and at the mooring lines have been carried out. First, free decay tests have been analysed to obtain the natural frequency and the modal damping ratios of each degree of freedom governing the offshore. Then, the results concerning regular waves, with orthogonal incidence to the structure, are presented. The results show that most of longitudinal dynamic response occurs at the wave frequency and most of lateral dynamic response occurs at rigid-body frequencies.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654110, HYDRALAB+

Immune challenges trigger cellular and humoral responses in adults of Pterostichus melas italicus (Coleoptera, Carabidae)

The present study focuses on the ability of Pterostichus melas italicus Dejean to mount cellular and humoral immune responses against invading pathogens. Ultrastructural analyses revealed the presence of five morphologically distinct types of hemocytes: prohemocytes, plasmatocytes, granulocytes, oenocytoids and macrophage-like cells. Differential hemocyte counts showed that plasmatocytes and granulocytes were the most abundant circulating cell types and plasmatocytes exhibited phagocytic activity following the latex bead immune challenge. Macrophage-like cells were recruited after the immune challenge to remove exhausted phagocytizing cells, apoptotic cells and melanotic capsules formed to immobilize the latex beads. Total hemocyte counts showed a significant reduction of hemocytes after latex bead treatment. Phenoloxidase (PO) assays revealed an increase of total PO in hemolymph after immune system activation with lipopolysaccharide (LPS). Moreover, the LPS-stimulated hemocytes showed increased protein expression of inducible nitric oxide synthase, indicating that the cytotoxic action of nitric oxide was engaged in this antimicrobial collaborative response. These results provide a knowledge base for further studies on the sensitivity of the P. melas italicus immune system to the environmental perturbation in order to evaluate the effect of chemicals on non-target species in agroecosystems

OC6 Phase II: Integration and verification of a new soil–structure interaction model for offshore wind design

This paper provides a summary of the work done within the OC6 Phase II project, which was focused on the implementation and verification of an advanced soil–structure interaction model for offshore wind system design and analysis. The soil–structure interaction model comes from the REDWIN project and uses an elastoplastic, macroelement model with kinematic hardening, which captures the stiffness and damping characteristics of offshore wind foundations more accurately than more traditional and simplified soil–structure interaction modeling approaches. Participants in the OC6 project integrated this macroelement capability to coupled aero-hydro-servo-elastic offshore wind turbine modeling tools and verified the implementation by comparing simulation results across the modeling tools for an example monopile design. The simulation results were also compared to more traditional soil–structure interaction modeling approaches like apparent fixity, coupled springs, and distributed springs models. The macroelement approach resulted in smaller overall loading in the system due to both shifts in the system frequencies and increased energy dissipation. No validation work was performed, but the macroelement approach has shown increased accuracy within the REDWIN project, resulting in decreased uncertainty in the design. For the monopile design investigated here, that implies a less conservative and thus more cost-effective offshore wind design