Conditional probability of distributed surface rupturing during normal-faulting earthquakes

Coseismic surface faulting is a significant source of hazard for critical plants and distributive infrastructure; it may occur either on the principal fault or as distributed rupture on nearby faults. Hazard assessment for distributed faulting is based on empirical relations which, in the case of normal faults, were derived almost 15 years ago using a dataset of US earthquakes. We collected additional case histories worldwide, for a total of 21 earthquakes, and calculated the conditional probability of distributed faulting as a function of distance from the principal fault. We found no clear dependency on the magnitude nor the time of occurrence of the earthquakes, but our data consistently show a higher probability of rupture when compared with the scaling relations currently adopted in engineering practice. We derive updated empirical regressions and show that the results are strongly conditioned by the averaging of earthquakes effectively generating distributed faulting at a given distance and those which did not generate faulting; thus, we introduce a more conservative scenario that can be included in a logic tree approach to consider the full spectrum of potential ruptures. Our results can be applied in the framework of probabilistic assessment of fault displacement hazard

Hydrogen vs. Battery in the long-term operation. A comparative between energy management strategies for hybrid renewable microgrids

The growth of the world’s energy demand over recent decades in relation to energy intensity and demography is clear. At the same time, the use of renewable energy sources is pursued to address decarbonization targets, but the stochasticity of renewable energy systems produces an increasing need for management systems to supply such energy volume while guaranteeing, at the same time, the security and reliability of the microgrids. Locally distributed energy storage systems (ESS) may provide the capacity to temporarily decouple production and demand. In this sense, the most implemented ESS in local energy districts are small–medium-scale electrochemical batteries. However, hydrogen systems are viable for storing larger energy quantities thanks to its intrinsic high mass-energy density. To match generation, demand and storage, energy management systems (EMSs) become crucial. This paper compares two strategies for an energy management system based on hydrogen-priority vs. battery-priority for the operation of a hybrid renewable microgrid. The overall performance of the two mentioned strategies is compared in the long-term operation via a set of evaluation parameters defined by the unmet load, storage efficiency, operating hours and cumulative energy. The results show that the hydrogen-priority strategy allows the microgrid to be led towards island operation because it saves a higher amount of energy, while the battery-priority strategy reduces the energy efficiency in the storage round trip. The main contribution of this work lies in the demonstration that conventional EMS for microgrids’ operation based on battery-priority strategy should turn into hydrogen-priority to keep the reliability and independence of the microgrid in the long-term operation

Statistical properties of stochastic 2D Navier-Stokes equations from linear models

A new approach to the old-standing problem of the anomaly of the scaling exponents of nonlinear models of turbulence has been proposed and tested through numerical simulations. This is achieved by constructing, for any given nonlinear model, a linear model of passive advection of an auxiliary field whose anomalous scaling exponents are the same as the scaling exponents of the nonlinear problem. In this paper, we investigate this conjecture for the 2D Navier-Stokes equations driven by an additive noise. In order to check this conjecture, we analyze the coupled system Navier-Stokes/linear advection system in the unknowns $(u,w)$. We introduce a parameter $\lambda$ which gives a system $(u^\lambda,w^\lambda)$; this system is studied for any $\lambda$ proving its well posedness and the uniqueness of its invariant measure $\mu^\lambda$. The key point is that for any $\lambda \neq 0$ the fields $u^\lambda$ and $w^\lambda$ have the same scaling exponents, by assuming universality of the scaling exponents to the force. In order to prove the same for the original fields $u$ and $w$, we investigate the limit as $\lambda \to 0$, proving that $\mu^\lambda$ weakly converges to $\mu^0$, where $\mu^0$ is the only invariant measure for the joint system for $(u,w)$ when $\lambda=0$.Comment: 23 pages; improved versio

Earthquake-triggered landslides and Environmental Seismic Intensity: insights from the 2018 Papua New Guinea earthquake (Mw 7.5)

On the 25 February 2018, an earthquake of magnitude M(w)7.5 struck the region of Porgera in Papua New Guinea (PNG), triggering numerous landslides. Planetscope images are used to derive a partial inventory of 2941 landslides in a cloud-free area of 2686 km(2). The average area of landslides in the study area is 18,500 m(2). We use the Environmental Seismic Intensity (ESI) scale to assess the damage due to the triggered landslides. Local intensity values are assigned to individual landslides by calculating their volume using various area-volume relations. We observe that different empirical relations yield similar volume values for individual landslides (local ESI intensity & GE; X). The spatial variation of landslide density and areal coverage within the study area in cells of 1 km(2) is investigated and compared to the probability predicted by the USGS model. We observe that high probability corresponds to a significant number of landslides. An ESI epicentral intensity of XI is estimated based on primary and secondary effects. This study represents the first application of the ESI scale to an earthquake in PNG. The Porgera earthquake fits well with past case studies worldwide in terms of ESI scale epicentral intensity and triggered landslide number as a function of earthquake magnitude

Characterization of self-injected electron beams from LWFA experiments at SPARC_LAB

The plasma-based acceleration is an encouraging technique to overcome the limits of the accelerating gradient in the conventional RF acceleration. A plasma accelerator is able to provide accelerating fields up to hundreds of $GeV/m$, paving the way to accelerate particles to several MeV over a short distance (below the millimetre range). Here the characteristics of preliminary electron beams obtained with the self-injection mechanism produced with the FLAME high-power laser at the SPARC_LAB test facility are shown. In detail, with an energy laser on focus of $1.5\ J$ and a pulse temporal length (FWHM) of $40\ fs$, we obtained an electron plasma density due to laser ionization of about $6 \times 10^{18}\ cm^{-3}$, electron energy up to $350\ MeV$ and beam charge in the range $(50 - 100)\ pC$.Comment: 6 pages, 11 figures, conference EAAC201

Oral malodor in Special Care Patients: current knowledge

Epidemiological studies report that about 50% of the population may have oral malodor with a strong social and psychological impact in their daily life. When intra-oral causes are excluded, referral to an appropriate medical specialist is paramount for management and treatment of extra-oral causes. The intra-oral causes of halitosis are highly common, and the dentist is the central clinician to diagnose and treat them. Pseudohalitosis or halitophobia may occur and an early identification of these conditions by the dentist is important in order to avoid unnecessary dental treatments for patients who need psychological or psychiatric therapy. The organoleptic technique is still considered the most reliable examination method to diagnose genuine halitosis. Special needs patients are more prone than others to have oral malodor because of concurrent systemic or metabolic diseases, and medications. The present report reviews halitosis, its implications, and the management in special care dentistry

Compared patterns of arm regeneration in different taxa of armed echinoderms

Regeneration is a post-embryonic developmental process common in Metazoa, although it tends to be less widespread in the more complex-bodied phyla. An exception to this rule are echinoderms, which are known for phylum-wide and extremely advanced regenerative abilities, being able to regrow all appendages, and often large parts of the central body and viscera (CANDIA CARNEVALI, 2006). Armed echinoderms (Crinoidea, Asteroidea, and Ophiuroidea) are especially practical models as their arms are easy to amputate, and their proximo-distal extension provides a useful reference point to describe the regenerative processes. Samples of four species from these taxa \u2013 the crinoid Antedon mediterranea, the asteroids Echinaster sepositus and Coscinasterias tenuispina, and the ophiuroid Amphipholis squamata \u2013 were subjected to arm amputation to study the progression of arm regeneration from a morphological point of view by means of different microscopy analyses. Particular attention was given to the \u201caxial structures\u201d, defined as the continuous elements running along the proximo-distal axis of each arm, namely the radial water canal, the radial nerve cord, and the arm coelom, as they are believed to be fundamental for the re-organization of the regenerating arm. The comparison highlighted commonalities and differences of arm regeneration in the different taxa. Distal structures, represented in crinoids by the apical blastema and in asteroids and ophiuroids by the terminal ossicle and tube foot, form very quickly, whereas the proximal region develops later, in proximal-to-distal direction. This is in accordance with previously published models of echinoderm regeneration (MOOI et al., 2005; BEN KHADRA et al., 2018). These similarities suggest that the mechanism of regeneration has ancient origins and is extremely conserved through echinoderm evolution. Within the proximal region, the axial structures themselves develop earlier than the nearby discrete structures (e.g. ossicles and tube feet), and seem to have a crucial role in their organization, providing material and possible signalling molecules for the growing tissue. The cellular component of the nerve grows before any other structure, including its own fibres, thus confirming a primary role of the nervous system in the whole process. Molecular analyses must be combined to morphology data to improve our understanding of similarities and differences of the regenerative process as it occurs in the different echinoderm taxa, as well as in different animal phyla, and to identify related processes in both regeneration-competent and non-competent species. References Ben Khadra Y, Sugni M, Ferrario C, Bonasoro F, Oliveri P, Martinez P, Candia Carnevali MD. 2018. Regeneration in Stellate Echinoderms: Crinoidea, Asteroidea and Ophiuroidea. M. Kloc, J. Z. Kubiak (eds.) Marine Organisms as Model Systems in Biology and Medicine. \ua9Springer International Publishing AG, part of Springer Nature 2018. Chapter 14 Candia Carnevali MD. 2006. Regeneration in Echinoderms: repair, regrowth, cloning. Invertebrate Survival Journal, 3 (1): 64-76 Mooi R, David B, Wray GA. 2005. Arrays in rays: terminal addition in echinoderms and its correlation with gene expression. Evolution & Development, 7 (6): 542-55