647 research outputs found
Built Heritage: Conservation vs. Emergencies
No full textSpecial Issue Information
Dear Colleagues,
According to the International Council on Monuments and Sites (ICOMOS) “International Charter for the Conservation and Restoration of Monuments and Sites” (also known as “The Venice Charter”, 1964), “conservation” relates to the systematic maintenance and use, without (important) modifications to heritage and with respect to its values. Conservation is not an exceptional event, but it an open-ended process of knowledge, understanding, maintenance, management, and enhancement, where sustainability, participation, and education are essential matters. Conservation also implies an attention to the environment, because heritage is related to natural, anthropic, cultural, and historical contexts. In particular, architectural and urban heritage fields require a specific reflection, because they are complex systems made by the stratification of transformations over time: They are living expressions of past events and cultures, and of present contingencies.
However, natural disasters (such as earthquakes, seaquakes, floods, etc.), wars, and also abandonment, pollution, or climate changes, put built heritage in danger and cause serious problems in conservation practices: In principle, conservation and disastrous events act as antinomic concepts. Moreover, all these considerations bring to the foreground the well-known issues of memory, identity, integrity, and authenticity.
This Special Issue of Buildings aims at focusing on issues growing from the relation/collision between conservation and emergencies, with case studies and examples of best practices: What is the role of knowledge in conservation and of surveying and documentation in emergencies? How conservation practices can prevent disasters or aid in reconstruction? How should we work, reconstruct and involve communities after a disaster?
Prof. Stefano Brusaporci
Prof. Giuseppe Amoruso
Guest Editor
Femtosecond laser pulse interaction with solid targets and investigations of the ablation plume.
No full textLaser ablation processes based on ultrafast (fs) pulses offer significant potential advantages over the case of conventional nanosecond lasers, as: i) the ability to decouple the ablated volume from the adjoint target mass; ii) the lowering of threshold ablation fluence by a factor of 10. This allows that also the most intractable materials, such as refractory metals, can be cleanly and congruently ablated. The study of the transport properties in laser-produced plasmas will be mainly carried out by time of flight mass spectrometry and optical spectroscopy, and can shed light on the different mechanisms involved in their formation and evolution in time and space [see e.g., S. Amoruso et al., J. Phys. B: At. Mol. Opt. Phys. 32, R131 (1999)], and to analyze possible applications in thin film deposition [see e.g., P.R. Willmott and J.R. Hubler, Rev. Mod. Phys. 72, 315 (2000)]
Ablazione Laser di Metalli con Impulsi Ultracorti - Ultrashort Laser Ablation of Metals
No full textThe project is in the field of interaction of ultrashort laser pulses with metals. The rapid development of short-pulsed laser systems over the last years offered opportunities for high-precision material processing and structuring of a wide range of materials – metals,1-3 semiconductors,4 and organic solids.5 Besides a variety of practical applications of ultrashort laser pulses they also reveal some new fundamental aspects of laser-beam interactions with matter. Laser ablation is a basic mechanism in a large number of applications for laser processing: cutting, drilling, surface cleaning, pulsed laser deposition of thin films, etc. Recent investigations showed that its theory and modeling are very complex. The process depends strongly on the material’s properties and the parameters of the laser source. Moreover, its theory requires the combination of several different areas of physics. This is why the fundamental physics underlying the laser ablation mechanism is still unclear. Additionally, the description is complicated in the case of ultrashort-pulse laser ablation because of the number of non-thermal processes involved. Many theoretical models have been developed recently,6-8 based generally on the heat conduction equation, hydrodynamics and molecular dynamics, which try to bring to light the basic features of short-pulse laser ablation process. According to these studies, several mechanisms of the ablation process can be realized, depending on the material and laser parameters. Some authors describe the ablation as melting followed by vaporization. Others indicate that a critical pressure gradient, arising in the short time interval after the laser interaction, is in the origin of the ejection process. In this case, the energy is deposited faster than the time of acoustic wave formation in the system, and the relaxation of the pressure gradient created leads to a significant material removal. On the other hand, if the laser pulse duration is shorter than the time for thermal relaxation of the system, defined by the thermal diffusion, overheating of the system can take place. Then, the temperature in the material reaches the critical point and a fast transition to a gaseous-liquid phase (phase explosion) occurs. Experimentally, basic properties and dynamics of ultrashort laser ablation have not yet been established, and experiments that focus on the ablated species are still rare. A few studies recently published have limited themselves to establish the presence of different species in the ablated plasma plume, namely ions, neutral atoms and nanoparticles.9-11 In the present context the formation of: i) nanoparticles with a diameter in the 1-10 nm range; ii) sub-keV to keV ions, during ultrashort laser ablation of solid targets, constitute aspects on great interest, due to their possible applications. In fact, the former (i) could open up new route to the production of nanoparticles resulting of special interest in the field of nanophysics and nanotechnology, while the latter (ii) is considered particularly promising for the current deficiency of sub-keV high-flux ion beams delivered by presently available commercial techniques. The main goals of the project are concentrated on: • development of a reliable numerical method based on Molecular dynamics simulation technique describing interaction of the ultrashort (<10 ps) laser radiation with metals; • detailed investigation of the process of ultrashort laser ablation of metals, including mechanisms of ablation, processes involved in the target material – phase transitions, shock wave evolution, crater formation, structure and evolution of the ablated material; • detailed experimental investigations of the characteristics of laser ablation driven by ultrashort laser pulses through the analysis of the ejected material, as well as on their variation as a function of the laser pulse characteristics (energy density, wavelength, e.g.). The result obtained in the frame of the project can be used in different areas of application of ultrashort lasers – precise micromachining, pulsed laser deposition of thin films, nanoparticles generation, etc., as well as they can reveals the physical nature of the processes involved. References: 1 S. Preuss, A. Demchuk, and M. Stuke, Appl. Phys. A 61, 33 (1995). 2 S. Nolte, C. Momma, H. Jacobs, A. Tünnermann, B.N. Chichkov, B. Wellegehausen, and H. Welling, J. Opt. Soc. B 14, 2716 (1997). 3 P.S. Banks, M.D. Feit, A.M. Rubenchik, B.C. Stuart, and M.D. Perry, Appl. Phys. A 69, 377 (1999) 4 D. von der Linde and K. Sokolowski-Tinten, Appl. Surf. Sci., 154, 1 (2000). 5 L.V. Zhigilei, P.B.S. Kodali, and B.J. Garrison, J. Phys. Chem. B 102, 2845 (1998). 6 A.M. Stonehman, M.M.D. Ramos, R.M. Ribeiro, Appl. Phys. A 69, S81 (1999) 7 L.V. Zhigilei, Appl. Phys. A 76, 339 (2003). 8 A.M. Rubenchik, M.D. Feit, M.D. Perry, J.T. Larsen, Appl. Surf. Sci., 127-129, 193 (1999). 9 O. Albert, S. Roger, Y. Glinec, J.C. Loulergue, J. Etcheparre, C. Boulme-Leborgne, J. Perriere, E. Millon, Appl. Phys. A 76, 319 (2003). 10 S. Amoruso, X. Wang, C. Altucci, C. de Lisio, M. Armenante, R. Bruzzese, N. Spinelli, R.Velotta, Appl. Surf. Sci. 186, 358 (2002). 11 M. Spyridaki, E. Koudoumas, P. Tzanetakis, C. Fotakis, R. Stojan, A. Rosenfeld, I.V. Hertel, Appl. Phys. Lett. 83, 1471 (2003). Our publications in the field: 1. N.N. Nedialkov, S.E. Imamova, P.A. Atanasov, G. Heusel, D. Breitling, A. Ruf, H. Hügel, F. Dausinger, P. Berger, Appl. Surf. Sci. accepted for publication (2003). 2. S. Amoruso, X. Wang, C. Altucci, C. de Lisio, M. Armenante, R. Bruzzese, N. Spinelli, R.Velotta, Appl. Surf. Sci. 186, 358 (2002). 3. P. Atanasov, N. Nedialkov, S. Imamova, A. Ruf, H. Hügel, F. Dausinger, P.Berger, Appl. Surf. Sci., 186, 369 (2002). 4. M. Obara, P.A. Atanasov, Y. Hirayama, K. Ozono, N.N. Nedialkov, S.E. Imamova, Proc. APLS’02, 1 (2002). 5. P. Atanasov, N. Nedialkov, S. Imamova, H. Hügel, F. Dausinger, A. Ruf, Proc. SPIE, 4397, 290 (2001). 6. S. Amoruso, Appl. Phys. A 69, 323 (1999). 7. S. Amoruso, R. Bruzzese, N. Spinelli, R.Velotta, J. Phys. B 32, R131 (1999)
Hydros Philia
No full textHydros Philia è il risultato delle ricerche condotte dall'autore come relatore della tesi di laurea di Chiara Amoruso. Le ricerche condotte durante un percorso di sperimentazione sulle possibilità sensoriali dei materiali si concretizzano nel progetto Hydros Philia, focalizzato sulla comunicazione percettiva delle superfici tessili e sul potenziamento delle loro qualità sensibili. I tessuti, elaborati secondo criteri dimensionali, composizioni di diversi materiali, densità e armature, sono così sottoposti a processi d’infeltrimento dando vita a super ci dalla forte attitudine comunicativa. Grazie all’incontro tra il laboratorio di ricerca del Politecnico di Bari di cui è responsabile l'autore e l’attività produttiva del Lanificio Leo è stato possibile realizzare una varietà di tessuti capaci di racchiudere il percorso di sperimentazione sensoriale definito dalla Tesi e di scandire una tassonomia di parametri tattili utili per la successiva applicazione dei materiali.Hydros Philia is the result of research conducted by the author as a supervisor for Chiara Amoruso's degree thesis..The research carried out during a trial on the sensory possibilities of a number of materials resulted in the Hydros Philia project, focused on perceived communication of textile surfaces and the enhancement of their tactile qualities. The fabrics, processed according to dimensional criteria, compositions of different materials, densities and weave, were thus subjected to felting processes, creating surfaces with strong communicative potential. Thanks to the meeting between the Bari Polytechnic Research Laboratory and the Lanificio Leo production company, it was possible to create a variety of fabrics capable of featuring the sensory test path as defined by the thesis and expressing a classification range of tactile parameters to be used in the subsequent application of the materials
A horizontal crack in a layered structure satisfies deformation for the 2004-2006 uplift of Campi Flegrei
No full textSources responsible for volcanic unrest produce characteristic surface deformation. Given a sufficient number of distributed observation points, inversion is the preferred procedure for retrieving the source parameters of location and volume or pressure change. Most often the solutions have been for point sources embedded in a homogeneous half-space. Recent work indicates that layered structures, particularly those with soft superficial layers, significantly perturb the deformation pattern compared with that for the homogeneous medium. We apply the methods of L. Crescentini and A. Amoruso to data for the most recent mini-uplift in the Campi Flegrei caldera and show that models using a homogeneous medium cannot adequately fit all the data. Incorporating a layered structure appropriate for Campi Flegrei allows a significantly better fit, avoiding characteristic discrepancies which are revealed by a synthetic test. Failure to use such structure results in incorrect source parameters, possibly leading to misleading geophysical interpretations
Chargel species analysis as a diagnostic tool for laser produced plasma characterization
No full textIn this work we report on a study of the plasma produced by UV (lambda = 351 nm) laser ablation of an aluminum target. In particular, we have directly measured the flux velocity of ablated ions along the normal to the metal target, the corresponding ion temperature, and the average kinetic energy by using an electrostatic energy analyzer. Moreover, by interpreting the measured ion energy distributions within the framework of the hydrodynamical model, we have also inferred an estimate of plasma electron density and temperature, which provide significant information on the laser plasma characterization in a number of applications. RI amoruso, salvatore/E-3941-2012; Berardi, Vincenzo/H-4550-2011; Velotta, Raffaele/I-5298-201
Analysis of the liquid argon purity in the ICARUS T600 TPC
No full textThe results reported in this paper are based on the analysis of the data recorded with the first half-module of the
ICARUS T600 liquid argon Time Projection Chamber (LAr TPC), during a technical run that took place on surface in
Pavia (Italy). We include results from the linearity, uniformity and calibration of the electronics, measurements on the
electron drift velocity in LAr at different electric fields, as well as the LAr purity achievement of the detector. Two
complementary techniques were used to measure the drift electron lifetime inside the active volume: the first, from the
data of a purity monitor, gives a measurement localized in space; the second, based on the study of the signals produced
by long minimum ionizing tracks crossing the detector, provides a LAr volume averaged value. Both methods yield
consistent results over the whole data taking period and are compatible with an uniform LAr purity over the whole
volume. The maximal drift electron lifetime value was recorded before the run stop and was about 1:8 ms: From an
interpretation of the observed drift electron lifetime as a function of time, we conclude that the adopted technology
would allow for drift distances exceeding 3 m
MEASUREMENT OF THE MU DECAY SPECTRUM WITH THE ICARUS LIQUID ARGON TPC
No full textExamples are given which prove the ICARUS detector quality through relevant physics measurements.
We study the μ decay energy spectrum from a sample of stopping μ events acquired during with fine granularity, hence, the precise measurement of the range and dE/dx of the μ with high sampling rate. This information is used to compute the calibration factors needed for the full calorimetric
reconstruction of the events. The Michel ρ parameter is then measured by comparison of the experimental
and Monte Carlo simulated μ decay spectra, obtaining ρ = 0.72 ± 0.06 (stat.) ± 0.08 (syst.). The energy
resolution for electrons below ∼ 50 MeV is finally extracted from the simulated sample, obtaining
(Eemeas − EeMC)/EeMC =
11%/E[MeV] ⊕ 2%
The perspective tabernacle of Bitonti and Borromini, the geometric protocol of baroque solid space
No full textThe paper presents the unpublished study of the tabernacle of San Paolo Maggiore (Bologna, 1647) designed as relief-perspective by Bitonti who partnered Borromini in the gallery of Spada palace in Rome (1653).
The perspective drawing, found at Bologna State Archive, depicts an architectural design rather than a furniture as documented by the Bolognese feet graphic scale. Bitonti follows the obliquazione rule of architectural orders settled by Caramuel while the order is the composite, already used by Bitonti in the perspective gallery painted in the Annunciation Church in Bitonto (1631)
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