Toppling dynamics of regularly spaced dominoes in an array

This is the author accepted manuscript. The final version is available from ASME via the DOI in this recordThis paper studies a new comprehensive model for toppling dynamics of regularly spaced dominoes in an array. The model has unlocked the hypotheses introduced by Stronge and Shu [1], which can provide us some essential insights into the mechanism of domino wave. Extensive comparisons are made between the proposed model and the experimental results studied in existing literature. Our numerical studies show that the existing theoretical models are special cases of the proposed model, and the fluctuation in the waveform of propagation speed observed from experiments was caused by the irregular multiple impacts between colliding dominoes. Influence of physical parameters of domino on the natural speed of toppling dominoes is also considered, and it is found that the coefficients of friction and restitution between colliding dominoes have more effects due to the energy dissipation during impact.This work was performed under the support of the National Natural Science Foundation of China (NSFC:11472011,11702002)

Crafting chaos: computational design of contraptions with complex behaviour

The 2010s saw the democratisation of digital fabrication technologies. Although this phenomenon made fabrication more accessible, physical assemblies displaying a complex behaviour are still difficult to design. While many methods support the creation of complex shapes and assemblies, managing a complex behaviour is often assumed to be a tedious aspect of the design process. As a result, the complex parts of the behaviour are either deemed negligible (when possible) or managed directly by the software, without offering much fine-grained user control. This thesis argues that efficient methods can support designers seeking complex behaviours by increasing their level of control over these behaviours. To demonstrate this, I study two types of artistic devices that are particularly challenging to design: drawing machines, and chain reaction contraptions. These artefacts’ complex behaviour can change dramatically even as their components are moved by a small amount. The first case study aims to facilitate the exploration and progressive refinement of complex patterns generated by drawing machines under drawing-level user-defined constraints. The approach was evaluated with a user study, and several machines drawing the expected pattern were fabricated. In the second case study, I propose an algorithm to optimise the layout of complex chain reaction contraptions described by a causal graph of events in order to make them robust to uncertainty. Several machines optimised with this method were successfully assembled and run. This thesis makes the following contributions: (1) support complex behaviour specifications; (2) enable users to easily explore design variations that respect these specifications; and (3) optimise the layout of a physical assembly to maximise the probability of real-life success

Crestal fault reactivation on rising salt diapirs: An integrated analysis from large to small scales of observation

The modes in which faults can propagate and grow through subsurface rocks and strata are key to the establishment of fluid paths in sedimentary basins; faults are potential conduits for fluid in some regions, at the same time they are associated with fault-related traps in others. The classical fault propagation models addressed in the published literature have so-far considered isolated, linkage (lateral-tip linkage and dip-linkage), constant-length, and coherent models. However, the propagation histories of faults in regions dominated by salt tectonics are scarcely documented; rather, the existing fault propagation models lack critical thinking when applied to crestal faults, particularly due to the limited resolution of imaged strata in most publications, and the relatively small size of crestal faults (length < 2.3 km, maximum throw < 50 m). With the increasing use of high-resolution seismic data in recent decades, it is now possible to undertake research into the evolution of both crestal faults and fluid flow paths in regions dominated by salt tectonics. In parallel, the uniqueness of crestal faults in terms of their scales has brought up important questions about how data resolution and scale variance influence many a fault analysis, and the current fault propagation models, when based on seismic and outcrop information. This research uses high resolution seismic data from the Espírito Santo Basin, offshore SE Brazil, to investigate the growth histories of crestal faults, fluid flow in an area of significant salt tectonics, and how crestal faults are associated with traps in supra- salt successions. To answer the question, in a second stage, of how scale variance can influence the analysis of faults’ propagation histories, data from Somerset (Bristol Channel) and the Ierapetra Basin (Crete) were collected in the field to broaden the database in this thesis from the larger, rift-basin scale to the seismic and sub-seismic scales. Segment linkage is predominant in areas where crestal faults grow. Interpreted crestal faults in SE Brazil propagated vertically and horizontally. Horizontal propagation was often hindered by natural barriers such as an accommodation zone (Chapter 4), or oblique transfer zones (Chapter 5), onto which faults terminate. Vertical propagation stopped when the fault meets the sea floor or when vertical propagation was accommodated by blind faults or larger (adjacent) faults showing relatively large displacements. Hence, this thesis shows that the propagation of crestal faults does not follow a ‘coherent growth model’. Rather, the geometry and history of propagation of discrete faults segments are not comparable. In SE Brazil, large fault segments propagated to link with non-reactivated small fault segments on the crest of the salt ridge, and can show later ‘blind’ propagation towards the surface. In terms of how scale variance can potentially (negatively) influence fault growth models interpreted on seismic data and in the field, a new quantitative method and two new parameters (sampling interval and module error) are introduced in this thesis for faults of multiple scales - from a few meters to 10s of kilometers. Sampling interval has a significant influence on the interpretation of fault growth histories. By changing one’s sampling interval: 1) the interpretation of fault geometries is significantly changed; 2) maximum fault throw values are underestimated; 3) fault segments are underrepresented; 4) the geometry of fault linkage zones is changed; 5) the width of fault linkage zones is underestimated; 6) fault interaction zones are lost. Using the SE Brazil seismic data, the accuracy of Throw-Distance plots was shown to be quantitatively lost when sampling intervals were larger than 37.5 m (every 3 shot-points) for the ‘unique’ crestal fault families in this thesis. However, this thesis demonstrates that sampling intervals adopted by interpreters should differ depending on the resolution of seismic data used, and the total length of investigated structures. A practical sampling interval/fault length ratio is therefore proposed in this work to address the caveats behind using variable (and indiscriminate) sampling intervals when analysing faults. Supra-salt sequences capable of promoting episodic fluid flow in regions of salt tectonics are of vital economic importance. Following on the two latter themes (crestal faulting and fault scaling), the thesis addressed the episodic fluid flow documented in the Espírito Santo Basin in a third stage. The results of this section are proposed as a case study for supra-salt sequences. In detail, seal failure is systematically recorded in the study area, and is interpreted to have contributed to most of the supra-salt fluid flow events investigated in SE Brazil. Six types of traps are therefore widely identified in supra-salt successions of the Espírito Santo Basin – all forming examples of trapping geometries in sedimentary basins associated with salt tectonics. Regardless of a thermogenic or diagenetic origin for fluid off Espírito Santo, the results in this thesis demonstrate important (and focused) fluid flow above salt giants when, at least, two critical conditions are observed: 1) a certain thickness of overburden strata is deposited on top of the salt structures, 2) the generation of highly developed (i.e. large) crestal fault systems is observed over these same salt structures. It is therefore postulated that, if overburden strata is thinner than a certain value, or pressure imposed by growing salt increases significantly, active salt intrusion occurring together with fluid flow will replace more focused fluid flow features in salt giants

Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)

This aim of paper is to presents the development of a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The goal of the project was the training in geospatial data acquiring and processing for students attending Architecture and Engineering Courses, in order to start up a team of "volunteer mappers". Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing. The proposed area for testing the training activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According to other international experiences, the group is expected to be active after emergencies in order to upgrade maps, using data acquired by typical geomatic methods and techniques such as terrestrial and aerial Lidar, close-range and aerial photogrammetry, topographic and GNSS instruments etc.; or by non conventional systems and instruments such us UAV, mobile mapping etc. The ultimate goal is to implement a WebGIS platform to share all the data collected with local authorities and the Civil Protectio

Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)

This aim of paper is to presents the development of a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The goal of the project was the training in geospatial data acquiring and processing for students attending Architecture and Engineering Courses, in order to start up a team of “volunteer mappers”. Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing. The proposed area for testing the training activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According to other international experiences, the group is expected to be active after emergencies in order to upgrade maps, using data acquired by typical geomatic methods and techniques such as terrestrial and aerial Lidar, close-range and aerial photogrammetry, topographic and GNSS instruments etc.; or by non conventional systems and instruments such us UAV, mobile mapping etc. The ultimate goal is to implement a WebGIS platform to share all the data collected with local authorities and the Civil Protection

Impact of Etna’s volcanic emission on major ions and trace elements composition of the atmospheric deposition

Mt. Etna, on the eastern coast of Sicily (Italy), is one of the most active volcanoes on the planet and it is widely recognized as a big source of volcanic gases (e.g., CO2 and SO2), halogens, and a lot of trace elements, to the atmosphere in the Mediterranean region. Especially during eruptive periods, Etna’s emissions can be dispersed over long distances and cover wide areas. A group of trace elements has been recently brought to attention for their possible environmental and human health impacts, the Technology-critical elements. The current knowledge about their geochemical cycles is still scarce, nevertheless, recent studies (Brugnone et al., 2020) evidenced a contribution from the volcanic activity for some of them (Te, Tl, and REE). In 2021, in the framework of the research project “Pianeta Dinamico”, by INGV, a network of 10 bulk collectors was implemented to collect, monthly, atmospheric deposition samples. Four of these collectors are located on the flanks of Mt. Etna, other two are in the urban area of Catania and three are in the industrial area of Priolo, all most of the time downwind of the main craters. The last one, close to Cesarò (Nebrodi Regional Park), represents the regional background. The research aims to produce a database on major ions and trace element compositions of the bulk deposition and here we report the values of the main physical-chemical parameters and the deposition fluxes of major ions and trace elements from the first year of research. The pH ranged from 3.1 to 7.7, with a mean value of 5.6, in samples from the Etna area, while it ranged between 5.2 and 7.6, with a mean value of 6.4, in samples from the other study areas. The EC showed values ranging from 5 to 1032 μS cm-1, with a mean value of 65 μS cm-1. The most abundant ions were Cl- and SO42- for anions, Na+ and Ca+ for cations, whose mean deposition fluxes, considering all sampling sites, were 16.6, 6.8, 8.4, and 6.0 mg m-2 d, respectively. The highest deposition fluxes of volcanic refractory elements, such as Al, Fe, and Ti, were measured in the Etna’s sites, with mean values of 948, 464, and 34.3 μg m-2 d-1, respectively, higher than those detected in the other sampling sites, further away from the volcanic source (26.2, 12.4, 0.5 μg m-2 d-1, respectively). The same trend was also observed for volatile elements of prevailing volcanic origin, such as Tl (0.49 μg m-2 d-1), Te (0.07 μg m-2 d-1), As (0.95 μg m-2 d-1), Se (1.92 μg m-2 d-1), and Cd (0.39 μg m-2 d-1). Our preliminary results show that, close to a volcanic area, volcanic emissions must be considered among the major contributors of ions and trace elements to the atmosphere. Their deposition may significantly impact the pedosphere, hydrosphere, and biosphere and directly or indirectly human health