Ambient vibrations of age-old masonry towers: results of long-term dynamic monitoring in the historic centre of Lucca

The paper presents the results of an ambient vibration monitoring campaign conducted on so-called Clock Tower (Torre delle Ore), one the best known and most visited monuments in the historic centre of Lucca. The vibrations of the tower were continuously monitored from November 2017 to March 2018 using high-sensitivity instrumentation. In particular, four seismic stations provided by the Istituto Nazionale di Geofisica e Vulcanologia and two three-axial accelerometers developed by AGI S.r.l., spin-off of the Istituto Nazionale di Astrofisica, were installed on the tower. The measured vibration level was generally very low, since the structure lies in the middle of a limited traffic area. Nevertheless, the availability of two different types of highly sensitive and accurate instruments allowed the authors to follow the dynamic behaviour of the tower during the entire monitoring period and has moreover provided cross-validation of the results

Characterization of the response of spring-based relative gravimeters during paroxysmal eruptions at Etna volcano

Gravity time sequences collected at Etna volcano by continuously recording spring-based relative gravimeters showed significant variations in temporal correspondence with paroxysmal eruptions. Since the observed gravity variations can only be partially related to subsurface mass redistribution phenomena, we investigated the instrumental effects due to ground vibrations such as those that accompany explosive activity. We simulated the performances of relative gravimeters with laboratory experiments to estimate their response to vertical and horizontal excitations. Laboratory tests were carried out using a vibrating platform capable of accelerating the instruments with intensities and frequencies, in both the vertical and horizontal directions, observed in the ground vibrations associated with paroxysmal events. The seismic signals recorded at Etna volcano during the 10 April 2011 lava fountain were analyzed to retrieve the parameters used to drive the vibration platform. We tested two gravimeters used for Etna volcano monitoring: the LaCoste & Romberg D#185 (Lafayette, CO, USA) and the Scintrex CG-3 M#9310234 (Concord, ON, Canada). The experiment results highlight that the vibrations resembling the seismic waves propagated during paroxysmal events cause an amplitude response in the gravity readings on the order of several hundred microgals (μGal). Generally, the relationship between the vibrations and the gravimeter response is nonlinear, with a fairly complex dependence on the frequencies and amplitudes of the signals acting on the gravimeters

Updates after the Near-Earth Commissioning Phase of Italian Spring Accelerometer – ISA

AbstractISA (Italian Spring Accelerometer) is a high sensitivity accelerometer flying, as scientific payload, on-board one of the two spacecraft (the Mercury Planetary Orbiter) of BepiColombo, the first ESA mission to Mercury. The first commissioning phase (performed in the period November 2018 - August 2019) allowed to verify the functionality of the instrument itself as well as of the related data handling and archiving system. Moreover, the acceleration measurements gathered in this time frame allow to envisage the potentiality of such an instrument as a high-accuracy monitor of the spacecraft mechanical environment

"Galileo Galilei" (GG) a small satellite to test the equivalence principle of Galileo, Newton and Einstein

"Galileo Galilei" (GG) is a small satellite designed to fly in low Earth orbit with the goal of testing the Equivalence Principle-which is at the basis of the General Theory of Relativity-to 1 part in 1017. If successful, it would improve current laboratory results by 4 orders of magnitude. A confirmation would strongly constrain theories; proof of violation is believed to lead to a scientific revolution. The experiment design allows it to be carried out at ambient temperature inside a small 1-axis stabilized satellite (250 kg total mass). GG is under investigation at Phase A-2 level by ASI (Agenzia Spaziale Italiana) at Thales Alenia Space in Torino, while a laboratory prototype (known as GGG) is operational at INFN laboratories in Pisa, supported by INFN (Istituto Nazionale di fisica Nucleare) and ASI. A final study report will be published in 2009

Long-Term Dynamic Monitoring of Medieval Masonry Towers

The aim of the paper is to present and discuss the results of an ambient vibration monitoring campaign conducted in the old town of Lucca, over the period 2015–2018. Despite the low level of the ambient vibrations in the historic center, using high-sensitivity instrumentation allowed the authors to measure and study the dynamic behavior of two medieval masonry towers: the San Frediano belfry and the Clock Tower. The main results of the dynamic identification of the towers are summarized, together with the variation over time of their dynamic properties. Some insights on the towers' response to the anthropic activities in the historic center are also presented. Finally, a finite element simulation is performed with the aim of assessing the influence of temperature variations on the towers' natural frequencies; good agreement is found between numerical and experimental results. The paper provides the scientific and technical community with a detailed report on a singular experiment in the field of architectural heritage.Fondazione Cassa di Risparmio di Lucca (TITANIO project, 2016–2018) and the Region of Tuscany and MIUR (MOSCARDO project, FAR-FAS 2014, 2016–2018)PublishedArticle 95T. Sismologia, geofisica e geologia per l'ingegneria sismicaN/A or not JC

Investigating fundamental physics and the space environment with a dedicated Earth-orbiting spacecraft

We propose a dedicated mission in low Earth orbit to test the gravitational interaction and place improved limits on the atmospheric density at the altitudes of interest. A very simple spacecraft would be placed in a dawn-dusk eccentric orbit between 500 and 1200 km. It should be tracked with high precision, and an on-board accelerometer would measure the non-gravitational accelerations acting on it. The precise orbit determination is expected to provide estimates of general relativistic predictions and of geophysical parameters, while the accelerometer data are fundamental in constraining the atmospheric density. Along with the scientific objectives, a basic mission configuration is described and discussed, highlighting the main issues to be explored. \ua9 2014 IEEE

Progress in the Critical Assessment for a Far-Infrared Space Interferometer with Double Fourier Modulation (FP7-FISICA)

The progress and results of the ongoing FP7-FISICA programme to re-asses the scientific goals of a Far-Infrared Space Interfereometer and push the development of some of its key technology elements are reported

Study on the Confirmation and a Variation of Slide Culture Method (S. C. M.) (【5th. Division】 Division of Biological Chemistry)

The progress and results of the ongoing FP7-FISICA programme to re-asses the scientific goals of a Far-Infrared Space Interfereometer and push the development of some of its key technology elements are reported