Acoustic (AE), electromagnetic (EME), and neutron (NE) emissions were measured during laboratory compression tests on rock specimens loaded up to failure.

Detecting prestressed wire breakage in concrete bridges is essential for ensuring safety and longevity and preventing catastrophic failures. This study proposes a novel approach for wire breakage detection using Mel‐frequency cepstral coefficients (MFCCs) and back‐propagation neural network (BPNN). Experimental data from two bridges in Italy were acquired to train and test the models. To overcome the limited availability of real‐world training data, data augmentation techniques were employed to increase the data set size, enhancing the capability of the models and preventing over‐fitting problems. The proposed method uses MFCCs to extract features from acoustic emission signals produced by wire breakage, which are then classified by the BPNN. The results show that the proposed method can detect and classify sound events effectively, demonstrating the promising potential of BPNN for real‐time monitoring and diagnosis of bridges. The significance of this work lies in its contribution to improving bridge safety and preventing catastrophic failures. The combination of MFCCs and BPNN offers a new approach to wire breakage detection, while the use of real‐world data and data augmentation techniques are significant contributions to overcoming the limited availability of training data. The proposed method has the potential to be a generalized and robust model for real‐time monitoring of bridges, ultimately leading to safer and longer‐lasting infrastructure.

In the Garisenda Tower of Bologna, several non-destructive (NDT) techniques are being used to examine structural damage and cracking evolution. The acoustic emission (AE) activity emerging from the masonry structures is analysed and related to surrounding temperature and strain measurements by distributed fibre optic sensors (FOSs). A seismometer was used to monitor low-frequency vibrations propagating across the ground-building foundation interface in order to examine the impact of local seismic activity or heavy vehicle traffic on tower vibration. The obtained data has led to the identification of several sources of AE activity, which apparently indicates the existence of an evolving cracking pattern. A consistent increase in the cumulated function of AE signals suggests that tower damage is caused by more than temperature changes. As a result, the origin of damage can be identified as the material's time-dependent creep behaviour under dead load and its interaction with fatigue generated by thermal fluctuations.

In the last few decades, several scientific papers have reported experimental evidence of anomalous nuclear reactions occurring in condensed matter during electrolytic phenomena or mechanical instabilities such as fracture (in solids) and cavitation (in liquids). Despite the numerous research activities carried out in the field of so-called “Cold Nuclear Fusion”, this phenomenon remains today not fully understood. In recent contributions by the authors, the formation of cracks on the surface of the electrodes used during electrolysis tests, together with chemical composition variations and anomalous sub-atomic particle emissions, were described. A mechanical interpretation of the experimental evidence can be based on low-energy phono-fission reactions, which are a conse- quence of hydrogen embrittlement, microcracking, and THz vibrations. In the present paper, the repeatable results of different laboratory testing programs obtained by means of Pd and Ni are discussed. Preliminary short notes about the energy balance close the paper.

Brittle crushing of iron-rich natural rocks was demonstrated to produce neutron emission, sometimes orders of magnitude larger than the environmental background. Chemical composition changes and a global ponderal equivalence, respecting atomic weight and atomic number balances, were observed. Phonons and plasmons induced by brittle crushing, if sufficiently energetic and resonant with the atomic lattice, may split the nucleus into different fragments and neutrons. It is relevant to emphasize how the earth’s crust evolution from basaltic to sialic can be consistently explained by these experimental data and theoretical assumptions when applied to tectonics.

Extensive experimental investigations were conducted on Gypsum and Quartz compression specimens of different sizes. They were brought to complete failure, showing two different failure modalities: (1) Very brittle loading drop for micro-crystalline Gypsum and Quartz; (2) Stable strain-softening behaviour for macro-crystalline Gypsum. All the tested specimens emitted acoustic and electromagnetic waves and the single events cumulated up to the peak load. On the other hand, neutron emissions were evident only for the largest specimens. The significant chemical composition changes occurring on the fracture surfaces are consistently explained by the assumption of Low-energy Nuclear Reactions (LENR), both fusion and fission. It is the first time that fusion reactions emerge from crushing tests, whereas fission reactions have already consistently explained the results related to other materials like the iron-rich natural rocks. Therefore, a correlation emerges between fusion nuclear reactions and strain-softening mechanical behaviour, as well as between fission nuclear reactions and brittle mechanical behaviour.

The study reported in this paper concerns the temporal variation in the b-value of the Gutenberg–Richter frequency–magnitude law, applied to the earthquakes that struck Italy from 2009 to 2016 in the geographical areas of L’Aquila, the Emilia Region, and Amatrice–Norcia. Generally, the b-value varies from one region to another dependent on earthquake incidences. Higher values of this parameter are correlated to the occurrence of low-magnitude events spread over a wide geographical area. Conversely, a lower b-value may lead to the prediction of a major earthquake localized along a fault. In addition, it is observed that each seismic event has a different “occurrence time”, which is a key point in the statistical study of earthquakes. In particular, its results are absolutely different for each specific event, and may vary from years to months or even just a few hours. Hence, both short- and long-term precursor phenomena have to be examined. Accordingly, the b-value analysis has to be performed by choosing the best time windows to study the foreshock and aftershock activities.

The premises for Law and Political Science faculties are an important milestone in the building programme of the University of Turin. Not far from the historical seat of the University, the Luigi Einaudi Campus has transformed an abandoned industrial area into a new cultural forum for the city. The geometric complexity of the layout, which originates from the free volumes designed by Foster + Partners, has led to a sophisticated internal spatial differentiation and to innovative solutions developed to give formal unity due to the roof solution. The system of the light-weight tent structures of the roof is characterized by fifty-two reticulated arches anchored at the reinforced concrete slabs on the top of each architectural volumes. The arches are topped by waterproof teflon-coated fiberglass membrane with high mechanical strength and stability against weathering. In this paper, a study of some most representative portions of the structure is proposed considering the influence of connection stiffness reductions. In particular, the robustness under conditions of reduced bracing and various stiffness configurations of the steel nodes of the interconnected arches is an evident problem to be assessed in these kinds of buildings.

In this contribution, in which the preliminary outcomes on the monitoring of the “Garisenda” Tower are discussed, there are also briefly presented the results already obtained from the monitoring of the “Asinelli” Tower, carried out a few years ago by the authors. The two medieval towers, recognized as the “twin towers” of Bologna, represent a remarkable symbol of the city and of Italian Architectural Heritage. The Asinelli Tower was built during the period 1109–1119. It rises to a height of 97.30 m above the ground, and shows a deviation from verticality of 2.38 m. The Garisenda Tower, built around the same time, is much smaller (48 m) but with a steeper leaning (3.22 m) due to an early and more marked subsidence of soil and foundation. The data collected during the AE monitoring period of the Asinelli Tower were analyzed to evaluate the damage progress in a certain region of the masonry structure and correlate it with other considered phenomena, such as the influence of vehicle traffic, seismic activity, and wind action. To arrive at a comprehensive and objective evaluation of the structural conditions of the Garisenda Tower, whose monitoring is still ongoing, the results obtained by the AE technique were supplemented with data obtained from other zones of the structure, subject to different stress–strain conditions or by means of other techniques. Thanks to this arrangement, the AE signals distribution is related to the data measured by optical cables and a seismometer to obtain an objective correlation between the actions generated by the environment and the tower damage.

Acoustic emissions (AE) due to microcracking in solid materials permit the monitoring of fracture processes and the study of failure dynamics. As an alternative method of integrity assessment, measurements of electrical resistance can be used as well. In the literature, however, many studies connect the notion of criticality with AE originating from the fracture, but not with the changes in the electrical properties of materials. In order to further investigate the possible critical behavior of fracture processes in rocks and cement-based materials, we apply natural time (NT) analysis to the time series of AE and resistance measurements, recorded during fracture experiments on cement mortar (CM) and Luserna stone (LS) specimens. The NT analysis indicates that criticality in terms of electrical resistance changes systematically precedes AE criticality for all investigated specimens. The observed greater unpredictability of the CM fracture behavior with respect to LS could be ascribed to the different degree of material homogeneity, since LS (heterogeneous material) expectedly offers more abundant and more easily identifiable fracture precursors than CM (homogenous material). Non-uniqueness of the critical point by varying the detection threshold of cracking events is apparently due to finite size effects which introduce deviations from the self-similarity.

High-frequency pressure waves (up to TeraHertz, 10^12 Hz), produced by mechanical instabilities at the nano-scale, can trigger fracto-emission signals in the form of Acoustic Emission AE, Electromagnetic Emission EME, and Neutron Emission NE. The same phenomenon can take place during the early stages of a seismic event. Cracking is a multi-scale phenomenon within the earthquake preparation zone, nano-cracks coalesce to form larger ones, and the preparation area shrinks until coinciding with the quake epicentre. At the same time, pressure wave frequencies vary from THz for fracture at the nano-scale up to the simple Hz at the kilometre scale, which is the typical frequency of seismic oscillations. In this framework, fracto-emissions can represent a promising tool in seismology, not only for their monitoring capabilities during the earthquake, but also for their forecasting potentialities before the event. Another important seismic precursor is represented by the temporal variation of the b-value, a sort of statistical parameter deriving from the magnitude-frequency relation proposed by Gutenberg and Richter, that is also successfully applied to study the cracking process. In general terms, the fracture moves from nano to macrocracks and the b-value decreases from about 1.5 in the initial stages to 1.0 or less approaching the final collapse. In seismology, values of unity are commonly related to an incoming seismic event: i.e. an earthquake is often preceded by a b-value decrement in the weeks to few days before the quake occurrence. Since July 2013, an in-situ experimental campaign has started at a gypsum mine located in Northern Italy, revealing the strong seismic forecasting potentialities of the fracto-emissions by means of a dedicated monitoring platform and a multi-modal statistical analysis. In particular, AE, EME, and NE tend to anticipate the next seismic swarm peak with an evident and chronologically ordered shifting of about one day, three-four days, and one week, respectively. On the other hand, the b-value trend, estimated for all the major seismic swarms observed during the in-situ monitoring, shows a decrement to values below 1.0 approximately one-two days before the swarm peak occurrence.

Fracto-emission signals (Acoustic Emission AE, Electromagnetic Emission EME, and Neutron Emission NE), triggered by high-frequency pressure waves at the different scales, can be used as a promising tool for environmental protection against seismicity. So far, no reliable method has been developed yet for the successful application of earthquake prediction because the physical mechanism of earthquakes and precursors is at present poorly understood, as well as the estimation of the so-called "earthquake preparation zone". On the other hand, recent studies are also re-evaluating the possible correlation between seismic activity and lunar periodicity. Since July 2013 an in-situ experimental campaign has started at a gypsum mine located in Northern Italy, revealing the strong seismic forecasting potentialities of the fracto-emission peaks by means of a dedicated monitoring platform and a mull-modal statistical analysis. In the present paper, an innovative interpretation of the earthquake preparation area is proposed, and the new experimental evidences obtained at the gypsum mine are reported confirming the previous results (Carpinteri and Borla, 2017). Finally, the relationship between small magnitude earthquake swarms occurred in the surroundings of the mine and the Moon phases is also investigated.

TeraHertz vibrations and pressure waves are produced at the nano-scale in solids and fluids by fracture and cavitation, respectively. They present a frequency that is close to the resonance frequency of the atomic lattices and an energy that is close to that of thermal neutrons. Original experiments performed on non-radioactive rocks under mechanical compression loading have shown repeatable neutron emissions in correspondence to micro- and macro-fracture. After these experiments, a considerable reduction in the iron content of the crushed rocks appears to be consistently counterbalanced by an increase in Al, Si, and Mg contents. At the same time, significant measurements of neutron emissions are observed at the Earth's Crust scale before and during seismic activity. In addition, several data coming from geochemistry and geomechanics have recently emphasized how tectonic activity should have been strictly connected to the most important changes in the Earth's Crust chemical composition over the last 4.5 Billion years. On these bases, the hypothesis of a new kind of low energy nuclear reactions finds confirmation and could be considered as a valid explanation for the geologic evolution of the Earth's Crust, Ocean, and Atmosphere. The same phenomenon appears to have occurred also in the chemical evolution of other planets of the Solar System like Mars, and of the Sun itself.

Three different forms of energy might be used as earthquake precursors for environmental protection against seismicity. At the tectonic scale, Acoustic Emission (AE) prevails, as well as Electro-Magnetic Emission (EME) at the intermediate scales, and Neutron Emission (NE) at the nano-scale. TeraHertz pressure waves are in fact produced at the last extremely small scale, and fracture experiments on natural rocks have recently demonstrated that these high-frequency waves are able to induce nuclear fission reactions with neutron and/or alpha particle emissions. Very important applications to earthquake precursors can be proposed. The authors present the results they are obtaining at a gypsum mine located in Northern Italy. In this mine, to avoid interference with human activities, the instrumental control units have been located at one hundred metres underground. The experimental results obtained from July 1st, 2013 to December 31, 2015 (five semesters) are analysed by means of a suitable multi-modal statistics. The experimental observations reveal a strong correlation between the three fracto-emission peaks (acoustic, electromagnetic, and neutron emissions) and the major earthquakes occurred in the surrounding areas. (C) 2017 Published by Elsevier Ltd.

Literature presents several cases of nuclear anomalies occurring in condensed matter, during fracture of solids, cavitation of liquids, and electrolysis. Previous papers by the authors have recently shown that, on the surface of the electrodes exposed to electrolysis, visible cracks and compositional changes are strictly related to nuclear particle emissions. In particular, a mechanical interpretation of the phenomenon was provided accounting the reactions due to hydrogen embrittlement effect. On the other hand, the authors have recently reported that appreciable neutron emissions far from the background level take place in hydrodynamic cavitation. In the present paper, specific measurements have been conducted during two experimental campaigns in order to evaluate the energy balance and the heat generation and its possible correlation to the same nuclear origin during both electrolysis and cavitation phenomena.

Three different forms of energy might be used as earthquake precursors for environmental protection against seismicity. At the tectonic scale, Acoustic Emission (AE) prevails, as well as Electro-Magnetic Emission (EME) at the intermediate scales, and Neutron Emission (NE) at the nano-scale. TeraHertz pressure waves are in fact produced at the last extremely small scale, and fracture experiments on natural rocks have recently demonstrated that these high-frequency waves are able to induce nuclear fission reactions with neutron and/or alpha particle emissions. The same phenomenon appears to have occurred in several different situations and to explain puzzles related to the history of our planet, like the ocean formation or the primordial carbon pollution. In addition, very important applications to earthquake precursors can be proposed. The authors present the results they are obtaining at a gypsum mine located in Northern Italy. In this mine, to avoid interference with human activities, the instrumental control units have been located at 100 m underground. The experimental results obtained from July 1st, 2013 to December 31, 2015 (five semesters) are analyzed by means of a suitable multi-modal statistics. The experimental observations reveal a strong correlation between the three fracto-emission peaks (acoustic, electromagnetic, neutron) and the major earthquakes occurring in the closest areas.

The main purpose of this Doctorate Thesis is to set-up a multi-parameter monitoring system that takes into account the observation of several seismic precursors. A seismic precursor is a phenomenon which can take place largely in advance to quake occurrence, and also at large distance from the epicentre. It is well known that the dimension of the earthquake preparation area is a function of the magnitude of the incoming quake and it can consist in a geographical zone up to thousands of kilometres. Furthermore, these precursory phenomena are of various nature but, despite their obvious diversity, many of them reflect a common physical origin. In the last decades a great number of laboratory tests and experimental observations evidenced that mechanical, electromagnetic and neutron emissions, together with radon levels, carbon dioxide emanations and temperature variation, are the most reliable natural phenomena that can be linked to earthquake preparation. In the finalization of this research many experimental tests were conducted both on the laboratory rock samples, and in a suitable monitoring site. First of all, specific tests carried out in the Fracture Mechanics Laboratory of the Politecnico di Torino are presented. Through these tests it was possible to demonstrate that the failure phenomena, in particular when they occur in a brittle way, i.e. with a mechanical energy release, emit additional forms of energy related to the fundamental natural forces. By subjecting brittle or quasi-brittle materials, such as rock specimens, to mechanical stress tests, bursts of neutron emission (NE) during the failure process were produced, necessarily involving nuclear reactions, besides the well-known acoustic emission (AE), and the phenomenon of electromagnetic radiation (EME). The main idea is that, if all these phenomena are simultaneously analysed in suitable monitoring sites, they could provide the basis for prediction of the three main parameters of an earthquake: place and time of occurrence, and magnitude of the seismic event. The place where it occurs is to be understood around the monitoring site, and in an area where its effects are always instrumentally perceptible. Nevertheless, the most important problem with all these precursors is to distinguish signals from noise. A single precursor may not be helpful, the prediction program strategy must involve an integral approach including different precursors. For the in-site monitoring the San Pietro - Prato Nuovo gypsum mine located in Murisengo (Alessandria, Italy) was chosen. In this mine, to avoid interference with human activities, the instrumental control units have been located at one hundred meters underground. Finally, the experimental results obtained from July, 1st 2013 to December, 31 2015 (five semesters) are reported. The experimental observations reveal a strong correlation between acoustic, electromagnetic, and neutron emission peaks and the major earthquakes occurred in the closest areas

Three different forms of emission might be used as earthquake precursors for environmental protection against seismicity. At the tectonic scale, Acoustic Emission (AE) prevails, as well as Electro- Magnetic Emission (EME) at the intermediate scales, and Neutron Emission (NE) at the nanoscale. TeraHertz pressure waves are in fact produced at the last extremely small scale, and fracture experiments on natural rocks have recently demonstrated that these high-frequency waves are able to induce nuclear fission reactions with neutron emissions. The authors present the results they are obtaining at a gypsum mine located in Northern Italy. The observations reveal a strong correlation between AE/EME/NE events and the major earthquakes in the surrounding area

The acoustic (AE) and electromagnetic (EM) emission signals detected during the failure of brittle materials are analogous to the anomalous mechanical and geoelectromagnetic waves observed before major earthquakes. These phenomena reinforce the idea that opto-acoustic emissions can be applied as a forerunning tool for seismic events. The elastic energy released by micro-cracking eventually yields to form macroscopic fractures, whose mechanical vibrations are converted into electromagnetic oscillations over a wide range of frequencies, from Hz to THz. This excited state of the matter could be the cause of resonance phenomena at the nuclear level producing neutron bursts, in particular during stress-drops or sudden catastrophic failures. The authors present the results they are obtaining at a gypsum mine located in Northern Italy. The observations revealed a strong correlation between AE/NE events and the closest and most intense earthquakes. Thanks to the position of the monitoring station (100 m under the ground level), the acoustic and electromagnetic noise from human activities is greatly reduced, as well as the neutron background. An integration of AE/EME/NE data with CO2 and Radon variations, that are considered as additional seismic precursors, is planned.