A study of dynamic respone of a lighting pole during a downburst through time-domain analysis and full-scale structural monitoring

The effect of downbursts on structures has been a topic of study for the past two decades. Numerical and analytical methods for the calculation of downburst wind loads and the dynamic response of structures have also been proposed. However, the proposed methods have not been verified using full-scale structural response data. This research presents the response of a monitored lighting pole during two downburst events, with a comparison of responses estimated through time-domain analysis. It is shown that the overall trend of the time history of the mean response is in close agreement with the registered response, and the fluctuating component of the response is highly dependent on the assumed wind field coherence

Application of CFD and mass-consistent models for operational wind forecasting

In the context of the San Paolo project "Wind monitoring, simulation and forecasting for the smart management and safety of port, urban and territorial system", a computational grid of Livorno City (Italy) and its surroundings at full scale has been constructed for 3D steady-state RANS simulations to be performed by the open-source code OpenFOAM. Field measurements in the same urban area have been scheduled between December 2017 and March 2018 in order to cover the entire winter season, i.e. the windiest one. The CFD results, obtained by initialising the CFD simulations with wind profiles measured through a LiDAR installed in the Port of Livorno, have been validated by means of two ultrasonic three-axial anemometers installed along a narrow canal which is located in the old city centre, about 1.5 km south-westward of the port area

Wind and structural response monitoring of a lighting pole for the study of downburst effects on structures

Wind excited response of structures due to downbursts has been studied using wind tunnel simulations, computational fluid dynamics applications, and analytical procedures in the previous two decades. However, the studies have not been validated with full-scale wind and structural response measurements. To fill this research gap, continuous wind-and-structural response monitoring of three slender structures was implemented through the European research council-funded project, THUNDERR. This paper focuses on one of the monitored structures, describing the monitoring system, the dynamic and aerodynamic properties, and the registered data during two downburst events. The wind-excited response of the monitored structure during two case studies of downbursts is analyzed. The correlation between the wind speed and structural displacement parameters was also studied and the square of mean wind speed was found to be highly correlated with the mean displacement and the standard deviation of the fluctuating displacement. The fluctuating components of wind speed and top displacement were found to be partially correlated. The simplicity of the selected structure, and the possibility of obtaining both the quasi-steady and resonant components of the structural response from strain registrations, will make this study a benchmark for the validation of methods and simulations of down burst wind load

Extreme wind speed distribution in a mixed wind climate

The meteorological services of mid-latitude countries record wind speeds averaged over 10 min or 1 h periods and peak wind speeds for the same averaging period or a full day. Design wind speeds based on the statistical analysis of this data in a mixed wind climate may prove to be imprecise and unsafe due to the occurrence of intense, small and rapid extreme wind events such as thunderstorm outflows. Considering the 6 year continuous high-frequency records registered in two Port areas of the Upper Tyrrhenian Sea, a preliminary but representative analysis of the extreme wind speed distribution has been carried out in a mixed wind climate area frequently struck by thunderstorms. Results show that wind speeds with a high return period are always related to thunderstorm outflows. The mixed extreme distribution asymptotically overlaps with that for thunderstorms for high return periods and always provides the highest wind speeds. Gathering the ensemble of all extreme values into a single set leads to underestimating of the extreme wind speed. The Italian code provides conservative estimates of the extreme wind speed that protect designers from thunderstorms as well. However, refined analyses of the local wind climate that ignore thunderstorm events may lead to severe underestimations of the design wind velocity

Indicator-based approach to evaluate the resilience of port infrastructures: application to the port of Genoa in the event of extreme weather conditions

The capacity of a community to react and resist to an emergency is strictly related to the proper functioning of its own infrastructure systems. Nodal infrastructure systems, like ports, provide essential services for modern societies. Seaports are critical engineering systems that provide continuous economic activities. Because of their natural location, these systems are exposed to various natural and manmade hazards that can significantly disrupt their services. While limiting the hazards is not possible, improving the resilience of the infrastructure is one of the manageable strategies that can be adopted. To do that, the current resilience state of the system must be identified. This paper proposes a new analytical framework for the assessment of ports’ resilience. The proposed framework is based on the PEOPLES framework. It comprises four dimensions: Physical infrastructures; Organisational and Governmental Services; Resources and Economy Development; and Territory and Environment, summarized under the acronym “PORT”. Each of the dimensions is further split into several components and sub-components to capture the detailed characteristics of the analysed infrastructure. The analysis starts by collecting all indicators related to seaports found in the literature as well as coming up with new indicators. The indicators are then classified under the four dimensions of PORT. Each indicator is given a weight factor to describe its contribution towards the resilience. Then, each indicator is allocated with a measure allowing the quantitative description of the indicator. A resilience curve for the port system is obtained as an output. The resulting resilience assessment allows identifying the current resilience state of the port and the aspects on which most efforts should be placed. The proposed methodology is applied to the port of Genoa for the case of extreme weather conditions. Future research is aimed at completing the quantitative description of the indicators, with the final aim of developing a user-friendly software tool to make the methodology more practical to use

Amyloid precursor protein and Presenilin1 interact with the adaptor GRB2 and modulate ERK 1,2 signaling.

The amyloid precursor protein (APP) and the presenilins 1 and 2 are genetically linked to the development of familial Alzheimer disease. APP is a single-pass transmembrane protein and precursor of fibrillar and toxic amyloid-beta peptides, which are considered responsible for Alzheimer disease neurodegeneration. Presenilins are multipass membrane proteins, involved in the enzymatic cleavage of APP and other signaling receptors and transducers. The role of APP and presenilins in Alzheimer disease development seems to be related to the formation of amyloid-beta peptides; however, their physiological function, reciprocal interaction, and molecular mechanisms leading to neurodegeneration are unclear. APP and presenilins are also involved in multiple interactions with intracellular proteins, the significance of which is under investigation. Among the different APP-interacting proteins, we focused our interest on the GRB2 adaptor protein, which connects cell surface receptors to intracellular signaling pathways. In this study we provide evidence by co-immunoprecipitation experiments, confocal and electron microscopy, and by fluorescence resonance energy transfer experiments that both APP and presenilin1 interact with GRB2 in vesicular structures at the centrosome of the cell. The final target for these interactions is ERK1,2, which is activated in mitotic centrosomes in a PS1- and APP-dependent manner. These data suggest that both APP and presenilin1 can be part of a common signaling pathway that regulates ERK1,2 and the cell cycle