Chapter Il progetto SEPA360 nella percezione degli studenti

This chapter focuses on the perception of the students about the video 360° and their didactic value in the academic teaching. The results of an online survey, administered to more than 200 students in three European countries who followed an academic course where a video 360° was used, are then presented and discussed highlighting how, despite the relative novelty of this tool for academic teaching, the results seem quite promising for their further adoption in the Higher Education

Endocannabinoid-related compounds in gastrointestinal diseases

The endocannabinoid system (ECS) is an endogenous signalling pathway involved in the control of several gastrointestinal (GI) functions at both peripheral and central levels. In recent years, it has become apparent that the ECS is pivotal in the regulation of GI motility, secretion and sensitivity, but endocannabinoids (ECs) are also involved in the regulation of intestinal inflammation and mucosal barrier permeability, suggesting their role in the pathophysiology of both functional and organic GI disorders. Genetic studies in patients with irritable bowel syndrome (IBS) or inflammatory bowel disease have indeed shown significant associations with polymorphisms or mutation in genes encoding for cannabinoid receptor or enzyme responsible for their catabolism, respectively. Furthermore, ongoing clinical trials are testing EC agonists/antagonists in the achievement of symptomatic relief from a number of GI symptoms. Despite this evidence, there is a lack of supportive RCTs and relevant data in human beings, and hence, the possible therapeutic application of these compounds is raising ethical, political and economic concerns. More recently, the identification of several EC-like compounds able to modulate ECS function without the typical central side effects of cannabinomimetics has paved the way for emerging peripherally acting drugs. This review summarizes the possible mechanisms linking the ECS to GI disorders and describes the most recent advances in the manipulation of the ECS in the treatment of GI diseases

SPH propagation back-analysis of Baishuihe landslide in south-western China

Background Landslides and landslide dams are a major natural hazard causing high socioeconomic risk in inhabited mountainous areas. This is also true for vast parts of south-western China, which are highly prone to slope failures due to several factors, such as a humid climate with high precipitation in the summer months, geological predisposing factors with highly weathered sedimentary rocks and a high seismicity. In order to assess possible run-out distances and the potential of landslides to block rivers, it is crucial to understand which factors influence landslide propagation and how they can be quantified. Since it is often difficult or impossible to measure related geotechnical parameters in the field, their back analysis with a numerical modelling approach can be useful. In this study a numerical modelling analysis was implemented for the case of a complex landslide in south-western China, which transformed into a debris flow and blocked the river and a major road after heavy rainfall. For this purpose a quasi-3D smoothed particle hydrodynamics (SPH) model that can account for geotechnical slope parameters, run-out distance, velocities, and deposition heights was used. Based on field observations regarding initial landslide volume and final deposition volume, height, and length, the mechanical properties of the landslide were estimated in a back-analysis

Remote damage inspection with AR custom headset

Nowadays key factors in high technology industries are digitalization, networking, data management, informatization and automation. The mutual interactions between these factors led toward the quickly evolving industrial revolution called “Industry 4.0” (or IR4) defined as the integration of new technologies within the design, manufacturing, and maintenance processes. This dynamic scenario is made possible by the so-called Internet of Things (IoT). In this context the inspection sector is rapidly upgrading in order to cope with the new technology paradigm of industry. The application of new technologies in NDE can improve the effectiveness, in terms of time and costs, of many inspection processes and include much more data and details exploiting multiple devices and sensing systems (NDE 4.0). In this work a remote damage inspection device is introduced, based on a stereo-laser depth map system connected to a custom headset. A laser speckle pattern is projected on the inspected component and acquired through a stereo cameras system. Damage is detected as a change in the depth map. The detected damage is then superimposed on the structure and streamed to the headset. The proposed idea would be extremely beneficial during the inspection process of large structures to assess whether a damage is present. This, in turn, would mak

an innovative algorithm to estimate risk optimum path for unmanned aerial vehicles in urban environments

Abstract The diffusion of the Unmanned Aerial Vehicles (UAVs) requires a suitable approach to define safe flight operations. In this paper, an innovative algorithm able to quantify the risk to the population and to search for the minimum risk path is proposed. The method has two main phases: in the former, a risk-map is generated quantifying the risk of a specific area, in the latter, a path planning algorithm seeks for the optimal path minimizing the risk. The risk-map is generated with a risk assessment method combining layers related to the population density, the sheltering factor, no-fly zones and obstacles. The risk-aware path planning is based on the well-known Optimal Rapidly-exploring Random Tree, with the minimization of the risk cost with respect to the flight time. Simulation results corroborate the validity of the approach

Chapter Didattica immersiva all’università: obiettivi e azioni del progetto SEPA360

This chapter introduces the relevance of the digital technologies for a constant update of the teaching and learning practices in the Higher Education and the challenges to cope with for their effective development, especially in the pandemic and post-pandemic period. The Erasmus+ project SEPA360 aiming at introducing the emerging technology of video 360° as a tool for helping the students in enhancing their capability in learning is then presented together with the activities carried out in the SEPA360 Consortium

On the fatigue improvement of railways superstructure components due to cold expansion – Part I: Experimental analysis

The fatigue strength improvement of materials and structures has always been the subject of studies, as a consequence of the rapid development of technologies and strictive safety requirements. In the railway field the fatigue resistance problem is thoroughly studied due to high transportation safety standard. Fatigue cracking is a major issue, in particular at rail-end-bolt holes. Cold Expansion is a common technique to induce beneficial residual compressive stresses around the holes, with the aim to improve the fatigue life of the rail. This paper is the first of a two part-series dealing with the study of the residual stress-strain field induced by the cold expansion process around rail-end-bolt holes. In Part I of this series, a contribution to better understanding the whole strain field distribution arising around rail-end-bolt holes during and after cold expansion is presented. Strains were experimentally measured using both electrical strain gauges and 2D-Digital Image Correlation. Contrary to common literature, strain-time history during the entire cold expansion process was investigated, in order to capture the highly non-linear elasto-plastic response of the material; the results of this study has been used in Part II of this series for the validation of the finite element model described there. The cold expansion process was applied to three rail holes, having equal nominal diameter. At first, the experimental results concerning each expanded hole are analysed. Then, all the results are compared, in order to evaluate the repeatability: - of the measurements; - of the Cold Expansion process; - of the adopted experimental technique, and, above all, to extrapolate the distribution of the hoop and radial residual strains as a function of the distance from the hole edge. At the end, results obtained by strain gauges and 2D-Digital Image Correlation are compared: a good agreement is found on the central flat surface of the rail web, which guarantees the availability of a robust and valuable highly non-linear reference result that has been used for the validation of the finite element model presented in Part II of this series

High velocity impact on generic CFRP blade specimen: baseline free method for impact localisation and damage assessment on complex structure

Nowadays components made of unidirectional composite materials are largely diffused in many engineering fields, such as automotive, railways, marine and aerospace. Main drawback of this class of materials lies in their low out-of-plane properties making them very sensible to impulsive loads such as impact events. After a collision with an external object, composites structures could be affected by damage, sometimes not visible from visual inspections (barely visible damage) hence with detrimental consequences on structure resistance and strength. Therefore, it is fundamental in terms of safety to continuously assess the healthy state of structures during their life and determine whether an impact event has occurred and if it caused damage or not. This work proposes a baseline free methodology to determine the coordinates of very high velocity impact on complex structures and evaluate if damage has occurred during the impact by only acquiring signal during the impact event. The technique overcomes the common limitations of previous technique presented in literature, i.e. a priori knowledge of mechanical properties, vibration response analysis, wave propagation direction dependency, sensor locations. The routine developed is based first on the estimation of the power of the acoustic emission generated by impact events, at sensors location, then the power information through the entire structure is reconstructed exploiting radial basis function network. The actual impact estimation is finally obtained using a weighted method. Furthermore, damage assessment is conducted with a novel method based on Hilbert–Huang transform and mode decomposition. Experimental tests were performed on a generic carbon fibre reinforced polymers blade specimen with a complex stacking sequence and embedded sensors. Two test configurations at different velocities were considered: one at 90 m s−1 and one at 190 m s−1. Before and afterwards the actual impact tests, the blade was excited as well with a modal hammer (pre and post impact). The results from the impact analysis highlighted the validity and reliability of the proposed method, with a high level of accuracy in terms of impact localisation estimation, and qualitative integrity state was effectively evaluated

On the fatigue improvement of railways superstructure components due to cold expansion – Part I: Experimental analysis

The fatigue strength improvement of materials and structures has always been the subject of studies, as a consequence of the rapid development of technologies and strictive safety requirements. In the railway field the fatigue resistance problem is thoroughly studied due to high transportation safety standard. Fatigue cracking is a major issue, in particular at rail-end-bolt holes. Cold Expansion is a common technique to induce beneficial residual compressive stresses around the holes, with the aim to improve the fatigue life of the rail. This paper is the first of a two part-series dealing with the study of the residual stress-strain field induced by the cold expansion process around rail-end-bolt holes. In Part I of this series, a contribution to better understanding the whole strain field distribution arising around rail-end-bolt holes during and after cold expansion is presented. Strains were experimentally measured using both electrical strain gauges and 2D-Digital Image Correlation. Contrary to common literature, strain-time history during the entire cold expansion process was investigated, in order to capture the highly non-linear elasto-plastic response of the material; the results of this study has been used in Part II of this series for the validation of the finite element model described there. The cold expansion process was applied to three rail holes, having equal nominal diameter. At first, the experimental results concerning each expanded hole are analysed. Then, all the results are compared, in order to evaluate the repeatability: - of the measurements; - of the Cold Expansion process; - of the adopted experimental technique, and, above all, to extrapolate the distribution of the hoop and radial residual strains as a function of the distance from the hole edge. At the end, results obtained by strain gauges and 2D-Digital Image Correlation are compared: a good agreement is found on the central flat surface of the rail web, which guarantees the availability of a robust and valuable highly non-linear reference result that has been used for the validation of the finite element model presented in Part II of this series

On the fatigue improvement of railways superstructure components due to cold expansion – Part II: Finite element prediction

This paper is the second of a two-part series dealing with the study of the residual stress field induced by cold expansion (CE) in rail-end-bolt holes. In the aeronautical field, cold expansion is a consolidated practice adopted to induce beneficial residual compressive stresses around holes of aluminium parts, with the aim to improve the fatigue strength. However, in the literature few experimental or numerical studies are proposed on the application of this technique to structural steels. In Part I, an in-depth experimental investigation was carried out on railway steel, in particular on rail-end-bolt holes, with the aim to better understand the full non-linear response of the material during the whole process. In this paper, finite element (FE) analyses simulating CE process are presented, and the experimental results of Part I have been used to validate the FE model. The strain-time history acquired during the entire cold expansion process allowed the comparison with FE-predicted strains, both in terms of residual and maximum strains. This approach is not present in literature, neither for aluminium nor for steel. The results, in terms of trend and magnitude, show that strains in both the experiments and the FE simulations are generally consistent, confirming the reliability of the FE model. In addition, a sensitivity study is presented for different levels of cold expansion. The results can be exploited to develop an a priori prediction of the residual stresses near the hole surface, aiming to an improvement of fatigue strength