3,946 research outputs found
Decommissioning of Offshore Platforms in Adriatic Sea: The Total Removal Option from a Life Cycle Assessment Perspective
No full textThe international energy scenario to date is heavily based on fossil energy sources such as coal, oil or natural gas. According to the international ecological goals of the UNFCCC formalized in the legally binding treaty called the Paris Agreement, the next global challenges will be the decommissioning, dismantling or reconversion of the current fossil energy system into a new, more sustainable system that makes more efficient use of renewable energy technologies. Worldwide, there are about 6500 offshore oil and gas facilities and about 130 of them are located in the Mediterranean basin, mainly in the Adriatic and Ionian Seas: more than 110 offshore gas platforms have been installed in these areas since 1960. In this paper, using Life Cycle Assessment, the environmental and economic impacts of the total removal operations of an existing offshore platform in the context of the Adriatic Sea are assessed based on existing and registered decommissioning projects. In addition, the avoided impacts of primary steel production due to its recovery and recycling from the removed platform are assessed using the system boundary expansion method
Il sistema di valutazione della sostenibilità ambientale visto attraverso l'ottica del progettista
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Modified POF Sensor for Gaseous Hydrogen Fluoride Monitoring in the Presence of Ionizing Radiations
No full textThis paper describes the development of a sensor designed to detect low concentrations of hydrogen fluoride (HF) in gas mixtures. The sensor employs a plastic optical fiber (POF) covered with a thin layer of glass- like material. HF attacks the glass and alters the fiber transmission capability so that the detection simply requires a LED and a photodiode. The coated POF is obtained by means of low-pressure plasma-enhanced chemical vapor deposition that allows the glass-like film to be deposited at low temperature without damaging the fiber core. The developed sensor will be installed in the recirculation gas system of the resistive plate chamber muon detector of the Compact Muon Solenoid experiment at the Large Hadron Collider accelerator of the European Organization for Nuclear Research (CERN
Prototype experiments of the low voltage mineral deposition technology as eco-friendly solution for improving the sustainability of offshore platforms at the end of their production life
No full textSeveral oil and gas offshore platforms are approaching the end of their production life, thus requiring sounding sustainable management solutions. This study aimed to improve the current knowledge on the low voltage mineral deposition technology as an eco-friendly strategy to protect offshore platforms from corrosion and to create suitable substrates for the colonization and growth of sessile marine organisms, thus minimizing environmental impact due to metal release, supporting biodiversity and increasing ecological sustainability. To do so, experimental prototype structures were installed in the Ligurian Sea (NW Mediterranean Sea) with the aim to simulate the sub-merged parts of offshore platforms and to analyze over time (up to ca. 6 months), elemental and chemical composition, growth rates and corrosion protection ability of the minerals deposited on steel substrates, through the alkalization induced by cathodic polarization of the metal. The influence of operational (applied current density) and natural environmental parameters on the deposition process was investigated. Results of this experiment revealed that in general the mineral deposits were mainly composed by aragonite (CaCO3) and brucite (Mg(OH)2) and, more specifically, the amount of the latter prevails a little bit on the amount of the former. This result is most likely related to high cathodic polarization current densities reached during the experimentation. Despite brucite is expected to worsen the physical–mechanical characteristics of the mineral deposits, the overall deposits were able to protect to a certain extent the electrified steel material from corrosion. After about 6 months of induced mineral deposition, the layer over the steel reached the maximum thickness of about 2.4 mm, following a non-linear trend as a function of time, whereas the deposition rates ranged from 20.0 to 50.3 μm d−1, in relation with the applied current densities. At the same time, a positive relationship of the deposit grow rates with seawater temperature has been observed. Overall, the outcomes reported in this study provide new elements for the application of low voltage mineral deposition technology in temperate seas and pave the way for defining the best operating conditions to protect steel structures from corrosion and support biodiversity, thus contributing to the sustainability of the natural capital
Local and global performance of double-gap resistive plate chambers operated in avalanche mode
No full textTwo large double-gap resistive plate chambers, with 2 and 3 mm gap widths, were tested to study their response uniformity when operated in avalanche mode. The effects of mechanical tolerances and the presence of the spacers is thoroughly examined. Results on efficiency and time resolution are presented. We find that average performance and response uniformity over the whole chamber surface are fully adequate to the requirements of future collider experiments. (author
{Search for at a Multi-TeV Muon Collider}
No full textA Multi-TeV (ss
= 1.5 - 10 TeV) Muon Collider providing O(ab−1)O(ab−1) integrated luminosity will be a great opportunity to probe the most intimate nature of the Standard Model (SM) and the Electroweak Symmetry Breaking mechanism, allowing the precise measurement of the Higgs couplings to several SM particles. The study of the Higgs boson couplings to the second generations of fermions is of particular interest due to sensitivity to a whole class of new physics models. It is also true that this measurement is extremely challenging, because of the small branching ratio. Indeed, it is currently not accessible at LHC, where the quantum chromodynamics processes are overwhelming. In this paper it is explored, for the first time, the search for H→ccˉH→ccˉ at a Multi-TeV Muon Collider. The μ+μ−→Hννˉ→ccˉννˉμ+μ−→Hννˉ→ccˉννˉ signal process has been fully simulated and reconstructed at s=1.5 TeVs
=1.5TeV with a preliminary detector design, along with the main physics backgrounds. The machine background originated from the decay of beam muons, the so-called Beam Induced Background (BIB), is not included in this preliminary study. A c quark-tagging algorithm has been developed, combining several observables in a single discriminator using Machine Learning techniques, with the goal to improve the rejection of jets coming from b-quark and u-d-s-g hadronization. A first estimate of the precision on the Higgs coupling with c-quark reachable with a Muon Collider machine is presented. The relative uncertainty on the coupling at s=1.5 TeVs
=1.5TeV is estimated to be 5.5 %%. A projection to s=3 TeVs
=3TeV shows that the precision improves with increasing energy, reaching the value of 2.6%2.6%
Progress on simulation and first prototype results on a beam monitor based on MPGD detectors for hadron therapy
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