Identification of aerodynamic damping matrix for operating wind turbines

© 2020 Elsevier Ltd Accurate knowledge of wind turbine tower vibration damping is essential for the estimation of fatigue life. However, the responses in the fore-aft and side-side directions are coupled through the wind-rotor interaction under operational conditions. This causes energy transfers and complicates aerodynamic damping identification using conventional damping ratios. Employing a reduced two-degree of freedom wind turbine model developed in this paper, this coupling can be accurately expressed by an unconventional aerodynamic damping matrix. Simulated time series obtained from this model were successfully verified against the outputs from the wind turbine simulation tool FAST. Based on the reduced system obtained, a matrix-based identification method is proposed to identify the aerodynamic damping for numerically simulated wind turbine tower responses. Applying harmonic excitations to the tower allowed the frequency response functions of the wind turbine system to be obtained and the aerodynamic damping matrix to be extracted. Results from this identification were compared to traditional operational modal analysis methods including standard and modified stochastic subspace identification. The damping in the fore-aft direction was successfully identified by all methods, but results showed that the identified damping matrix performs better in capturing the aerodynamic damping and coupling for the side-side responses

Experimental and Numerical Investigation of a Direct Injection Spark Ignition Hydrogen Engine for Heavy-Duty Applications

International audienceThe H2 internal combustion engine is gaining increasing interest especially for commercial vehicles. Regarding the optimization of the combustion process, results of experimental investigations on a H2 heavy-duty single-cylinder engine in combination with numerical 3D-CFD investigations are presented. In addition to a Direct Injection (DI) Spark Ignited (SI) configuration, Port Fuel Injection (PFI) is explored to provide a reference with near homogeneous cylinder charge. The main objective is to assess a 3D-CFD-RANS framework based on ECFM and state-of-the art sub-models to describe the most important phenomena occurring in H2 spark ignition engines and to support the experimental analysis. Experimental results show that the PFI configuration provides efficiency and emissions benefits at the expense of volumetric efficiency. The proposed CFD model demonstrates the ability to successfully simulate different engine operating conditions for both PFI and DI systems. In particular, it is shown that the charge stratification typical for DI systems is not beneficial for the studied configuration as it increases wall heat losses and NOx formation

A MAGE-3 peptide presented by HLA-B44 is also recognized by cytolytic T lymphocytes on HLA-B18

Antigens encoded by MAGE genes are of particular interest for cancer immunotherapy because of their tumoral specificity and because they are shared by many tumors. Antigenic peptide MEVDPIGHLY, which is encoded by MAGE-3 and is known to be presented by human leukocyte antigen (HLA)-B44, is currently being used in therapeutic vaccination trials. We report here that a cytolytic T lymphocyte (CTL) clone, which is restricted by HLA-B*1801, recognizes the same peptide and, importantly, lyzes HLA-B18 tumor cells expressing MAGE-3. These results imply that the use of peptide MEVDPIGHLY can now be extended to HLA-B18 patients. We also provide evidence that, under limiting amounts of protein MAGE-3, HLA B*1801 and B*4403 compete for binding to the peptide