Shock Tube Study of the Thermal Conductivity of Argon

Analysis of end-wall thermal boundary layer behind reflected shock to determine thermal conductivity of argon over temperatures 3150 to 9225

Integrated Geomechanical and Digital Photogrammetric Survey in the Study of Slope Instability Processes of a Flysch Sea Cliff (Debeli Rtic Promontory, Slovenia)

This work presents an integrated study approach that combines the results of a geomechanical survey with data obtained using digital photogrammetry (DP), to assess slope instability processes affecting a sea cliff at the Debeli Rtic promontory (Slovenia). The investigated cliff is 4-18 m-high and is made up of an alternation of sandstones and marlstones belonging to the Flysch Formation of Trieste, which is Eocene in age. The studied cliff was subjected to localized slope failures that occurred in the past and is currently subject to frequent rock collapses, thus resulting in its partial and episodic retreat. Field evidence acquired through a traditional survey was integrated with outputs of the DP technique based on 1399 images that were collected using both a commercial unmanned aerial vehicle (UAV) and a mobile phone (MP). UAV-derived images were useful for performing rock mass structure analysis in the upper part of the investigated cliff, where the traditional survey was not possible due to hazardous operating conditions. In addition, the use of a MP was observed to be a useful tool for the rapid collection of images at the toe of unsafe marine cliff environments. This study highlights that UAV-DP and MP-DP techniques can only be effective if the outcomes obtained from the 3D model reconstruction are validated by direct measurements acquired by means of the traditional field survey, thus avoiding improper or even erroneous results while enlarging the amount of data and the area of investigation. The study approach presented herein allowed for the assessment of slope instabilities affecting the Flysch Sea cliff, whose retreat is caused by the combined action of marine erosion and slope gravitational processes

Integrated Geomechanical and Digital Photogrammetric Survey in the Study of Slope Instability Processes of a Flysch Sea Cliff (Debeli Rtič Promontory, Slovenia)

This work presents an integrated study approach that combines the results of a geomechanical survey with data obtained using digital photogrammetry (DP), to assess slope instability processes affecting a sea cliff at the Debeli Rtič promontory (Slovenia). The investigated cliff is 4–18 m-high and is made up of an alternation of sandstones and marlstones belonging to the Flysch Formation of Trieste, which is Eocene in age. The studied cliff was subjected to localized slope failures that occurred in the past and is currently subject to frequent rock collapses, thus resulting in its partial and episodic retreat. Field evidence acquired through a traditional survey was integrated with outputs of the DP technique based on 1399 images that were collected using both a commercial unmanned aerial vehicle (UAV) and a mobile phone (MP). UAV-derived images were useful for performing rock mass structure analysis in the upper part of the investigated cliff, where the traditional survey was not possible due to hazardous operating conditions. In addition, the use of a MP was observed to be a useful tool for the rapid collection of images at the toe of unsafe marine cliff environments. This study highlights that UAV-DP and MP-DP techniques can only be effective if the outcomes obtained from the 3D model reconstruction are validated by direct measurements acquired by means of the traditional field survey, thus avoiding improper or even erroneous results while enlarging the amount of data and the area of investigation. The study approach presented herein allowed for the assessment of slope instabilities affecting the Flysch Sea cliff, whose retreat is caused by the combined action of marine erosion and slope gravitational processes

Re-identification of objects from aerial photos with hybrid siamese neural networks

In this paper, we consider the task of re-identifying the same object in different photos taken from separate positions and angles during aerial reconnaissance, which is a crucial task for the maintenance and surveillance of critical large-scale infrastructure. To effectively hybridize deep neural networks with available domain expertise for a given scenario, we propose a customized pipeline, wherein a domain-dependent object detector is trained to extract the assets (i.e., sub-components) present on the objects, and a siamese neural network learns to re-identify the objects, exploiting both visual features (i.e., the image crops corresponding to the assets) and the graphs describing the relations among their constituting assets. We describe a real-world application concerning the re-identification of electric poles in the Italian energy grid, showing our pipeline to significantly outperform siamese networks trained from visual information alone. We also provide a series of ablation studies of our framework to underline the effect of including topological asset information in the pipeline, learnable positional embeddings in the graphs, and the effect of different types of graph neural networks on the final accuracy

Landslide susceptibility modeling assisted by Persistent Scatterers Interferometry (PSI): an example from the northwestern coast of Malta

Persistent Scatterers Interferometry (PSI) techniques are widely employed in geosciences to detect and monitor landslides with high accuracy over large areas, but they also suffer from physical and technological constraints that restrict their field of application. These limitations prevent us from collecting information from several critical areas within the investigated region. In this paper, we present a novel approach that exploits the results of PSI analysis for the implementation of a statistical model for landslide susceptibility. The attempt is to identify active mass movements by means of PSI and to avoid, as input data, time-/cost-consuming and seldom updated landslide inventories. The study has been performed along the northwestern coast of Malta (central Mediterranean Sea), where the peculiar geological and geomorphological settings favor the occurrence of a series of extensive slow-moving landslides. Most of these consist in rock spreads, evolving into block slides, with large limestone blocks characterized by scarce vegetation and proper inclination, which represent suitable natural radar reflectors for applying PSI. Based on geomorphometric analyses and geomorphological investigations, a series of landslide predisposing factors were selected and a susceptibility map created. The result was validated by means of cross-validation technique, field surveys and global navigation satellite system in situ monitoring activities. The final outcome shows a good reliability and could represent an adequate response to the increasing demand for effective and lowcost tools for landslide susceptibility assessment

The Mellin moments of deep inelastic structure functions at two loops

We perform the analytic calculation of the Mellin moments of the structure functions F_2 and F_L in perturbative QCD up to second order corrections and in leading twist approximation. We calculate the 2-loop contributions to the anomalous dimensions of the singlet and non-singlet operator matrix elements and the 2-loop coefficient functions of F_2 and F_L. Our results are in agreement with earlier calculations in the literature.Comment: 4 pages LaTeX, talk given at the QCD 99 Euroconference, Montpellier (France

High energy photon-neutrino elastic scattering

The one-loop helicity amplitudes for the elastic scattering process $\gamma\nu\to\gamma\nu$ in the Standard Model are computed at high center of mass energies. A general decomposition of the amplitudes is utilized to investigate the validity of some of the key features of our results. In the center of mass, where $\sqrt{s} = 2\omega$, the cross section grows roughly as $\omega^6$ to near the threshold for $W$-boson production, $\sqrt{s} = m_W$. Although suppressed at low energies, we find that the elastic cross section exceeds the cross section for $\gamma\nu\to\gamma\gamma\nu$ when $\sqrt{s}>13$ GeV. We demonstrate that the scattered photons are circularly polarized and the net value of the polarization is non-zero. Astrophysical implications of high energy photon-neutrino scattering are discussed.Comment: 9 pages, 7 figures, RevTeX

Measurement of the WW and WZ production cross section using final states with a charged lepton and heavy-flavor jets in the full CDF Run II data set

We present a measurement of the total WW and WZ production cross sections in p (p) over bar collision at root s = 1.96 TeV, in a final state consistent with leptonic W boson decay and jets originating from heavy-flavor quarks from either a W or a Z boson decay. This analysis uses the full data set collected with the CDF II detector during Run II of the Tevatron collider, corresponding to an integrated luminosity of 9.4 fb(-1). An analysis of the dijet mass spectrum provides 3.7 sigma evidence of the summed production processes of either WW or WZ bosons with a measured total cross section of sigma(WW+WZ) = 13.7 +/- 3.9 pb. Independent measurements of the WW and WZ production cross sections are allowed by the different heavy- flavor decay patterns of the W and Z bosons and by the analysis of secondary- decay vertices reconstructed within heavy- flavor jets. The productions of WW and of WZ dibosons are independently seen with significances of 2.9s and 2.1s, respectively, with total cross sections of sigma(WW) = 9.4 +/- 4.2 pb and sigma(WZ) = 3.7(-2.2)(+2.5) pb. The measurements are consistent with standard- model predictions.Peer reviewe

Measurement of the differential cross sections for W-boson production in association with jets in p(p)over-bar collisions at root s=1.96 TeV

This paper presents a study of the production of a single W boson in association with one or more jets in proton-antiproton collisions at is root s = 1.96 TeV, using the entire data set collected in 2001-2011 by the Collider Detector at Fermilab at the Tevatron, which corresponds to an integrated luminosity of 9.0 fb(-1). The W boson is identified through its leptonic decays into electron and muon. The production cross sections are measured for each leptonic decay mode and combined after testing that the ratio of the W(-> mu v) + jets cross section to the W(-> ev) + jets cross section agrees with the hypothesis of e-mu lepton universality. The combination of measured cross sections, differential in the inclusive jet multiplicity (W + >= N jets with N = 1, 2, 3, or 4) and in the transverse energy of the leading jet, are compared with theoretical predictions.Peer reviewe