244 research outputs found
The Very High Energy source catalog at the ASI Science Data Center
The increasing number of Very High Energy (VHE) sources discovered by the
current generation of Cherenkov telescopes made particularly relevant the
creation of a dedicated source catalogs as well as the cross-correlation of VHE
and lower energy bands data in a multi-wavelength framework. The "TeGeV
Catalog" hosted at the ASI Science Data Center (ASDC) is a catalog of VHE
sources detected by ground-based Cherenkov detectors. The TeGeVcat collects all
the relevant information publicly available about the observed GeV/TeV sources.
The catalog contains also information about public light curves while the
available spectral data are included in the ASDC SED Builder tool directly
accessible from the TeGeV catalog web page. In this contribution we will report
a comprehensive description of the catalog and the related tools.Comment: 5 pages, 3 figures - Proceeding of the 34th International Cosmic Ray
Conferenc
Constraining the Timing of Evolution of Shear Zones in Two Collisional Orogens: Fusing Structural Geology and Geochronology
In recent decades, constraining the timing of shear activity has been one of the main topics of research about the tectono-metamorphic evolution of orogenic belts. We present a review of a combined structural and geochronological approach to two major ductile regional shear zones, in two collisional orogens: the first one affecting the Variscan basement in northern Sardinia (Italy) and the External Crystalline Massifs of the Alps (East Variscan Shear Zone; EVSZ), and the second one deforming the medium- to high-grade rocks of the metamorphic core of the Himalaya (High Himalayan Discontinuity). High-resolution, texturally and chemically controlled monazite geochronology applied in separated shear zones of the Variscan belt allowed recognizing a similar timing of activity ranging between c. 340–330 and 300 Ma. This approach led to a better understanding of the evolution of the EVSZ, supporting a model where several branches were active according to a growth by linkage model. Following a similar approach, in situ U-Th-Pb analysis of monazite constrained the timing of top-to-the-S/SW shearing of a regional-scale High Himalayan Discontinuity in the Himalayan belt to between c. 28 Ma and 17 Ma. Earlier exhumation of the hanging wall was triggered by shear zone activity, whereas at the same time, the footwall was still experiencing burial with increasing P-T conditions. The timing of shearing of this shear zone fits with an in-sequence shearing tectonic model for the exhumation of the Himalayan mid-crust
Direct artificial aging of the PBF-LB AlSi10Mg alloy designed to enhance the trade-off between strength and residual stress relief
The AlSi10Mg alloy is one of the most studied alloys processed by the Powder Bed Fusion-Laser Beam (PBF-LB). Many already published works focus on post-process heat treatments to reduce residual stress or improve me- chanical strength. Instead, the present study aims to identify direct artificial aging (AA) heat treatment able to optimize both aspects, thus enhancing the trade-off between strengthening and residual stress relief for the PBF- LB AlSi10Mg alloy produced using a no-heated platform. Higher temperatures (190–240 ◦C) than those typically used in AA heat treatment were selected based on thermal analysis to benefit both residual stress relief and precipitation of reinforcing phases from the supersaturated solid solution of the metastable as-built alloy. The effects of AA heat treatment on mechanical properties (i.e. hardness) and residual stress were evaluated by plotting aging curves and by XRD and Raman analyses and demonstrated that different trade-offs between strengthening and stress relief can be achieved by tuning heat treatment parameters (temperature and time). In particular, the exposure at the lowest temperature (190 ◦C) induced a partial decrease in residual stress and a slight increase in hardness. By increasing heat treatment temperature and soaking time, the relief was more significant, whilst the decrease in hardness was rather limited. The results are supported by the microstructural changes observed on the samples due to the different heat treatment conditions applied and show the feasibility of designing an AA heat treatment for the PBF-LB AlSi10Mg alloy capable of satisfying the mechanical response required by the final application
Accuracy of complete-arch digital implant impression with intraoral optical scanning and stereophotogrammetry: An in vivo prospective comparative study
Objectives: To assess accuracy of intraoral optical scanning (IOS) and stereophotogrammetry (SPG), complete-arch digital implant impressions in vivo. Materials and Methods: Consecutive patients needing implant-supported screw-retained zirconia complete-arch fixed-dental prostheses (ISZ-FDP) were recruited. For each patient, three impressions were taken: IOS, SPG (tests), and open-tray plaster (reference). Linear (ΔX, ΔY, and ΔZ), three-dimensional (ΔEUC), and angular deviations (ΔANGLE) were evaluated and stratified according to scanning technology for each implant. Potential effects of impression device (IOS and SPG), arch (maxilla and mandible), and implant number (4 and 6) were evaluated through multivariable analysis. Significance level was set at.05. Results: A total of 11 complete arches (5 maxillae, 6 mandibles) in 11 patients were rehabilitated with ISZ-FDPs supported by 4 (n = 8) and 6 implants (n = 3). A total of 50 implants and 100 implant positions were captured by two investigated devices and compared to respective reference (mean ΔEUC IOS 137.2, SPG 87.6 μm; mean ΔANGLE 0.79, 0.38°). Differences between measurements (SPG-IOS) were computed for each implant, with negative values indicating better SPG accuracy. Significant mean ΔEUC difference of −49.60 μm (p =.0143; SD 138.15) and mean ΔANGLE difference of −0.40° (p <.0001; SD 0.65) were observed in favor of SPG. Multivariable analysis showed significant effect on ΔEUC (p =.0162) and ΔANGLE (p =.0001) only for impression devices, with SPG performing better. Conclusions: SPG experienced significantly higher linear and angular accuracy. No effect of type of arch or implant number was detected. Higher extreme deviations were experienced for IOS. SPG can be feasible for complete-arch digital impressions with caution, and rigid prototype try-in is recommended before screw-retained prosthesis manufacturing. © 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
PENGARUH CAMPURAN ABU AMPAS KAYU PADA TANAH DESA COT SEUNONG DENGAN PENGUJIAN CALIFORNIA BEARING RATIO
Tanah yang tersedia di alam sering tidak dapat langsung digunakan karena secara alamiah tanah memiliki sifat-sifat fisis dan mekanis tertentu yang terbatas. Oleh karena itu diperlukan penelitian tentang tanah untuk mengetahui sifat-sifatnya dengan teliti sehingga dapat menyesuaikan dengan kebutuhan konstruksi sehingga menjamin stabilitas suatu konstruksi. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan abu ampas kayu yang digunakan sebagai bahan stabilisasi terhadap nilai CBR (California Bearing Ratio). Tanah yang digunakan dalam penelitian ini berasal dari Desa Cot Seunong Kecamatan Montasik Kabupaten Aceh Besar. Abu ampas kayu yang diperoleh diambil dari sisa-sisa limbah perabot pembuatan kayu yang berada di daerah Desa Kajhu Aceh Besar. Tanah tersebut menurut klasifikasi AASHTO tergolong A-7-6 (tanah berlempung). Menurut USCS tanah Desa Cot Seunong termasuk golongan tanah lempung tak organik dengan plastisitas tinggi yang disimbolkan CH (Clay High) dengan indeks plastisitasnya adalah 33,69%. Persentase penambahan abu ampas kayu yaitu 0%, 5%, 10%, 15% dan 20% terhadap berat kering tanah. Hasil pengujian Standart Proctor tanpa campuran didapat nilai OMC (Optimim Moisture Content) 23,60% dengan berat isi kering maksimum (?dmax) 1,595 gr/cm3. Hasil pengujian CBR memperlihatkan bahwa nilai CBR pada persentase 0% sebesar 1,67%, pada persentase 5% sebesar 2,45%, pada persentase 10% sebesar 2,62%, pada persentase 15% sebesar 2,73%, dan pada persentase 20% sebesar 3,03%. Nilai CBR tertinggi terdapat pada persentase 20% dengan nilai CBR 3,03%, dengan demikian penggunaan abu ampas kayu pada tanah lempung Desa Cot Seunong sangat efektif karena semakin banyak campuran abu ampas kayu yang mengisi pori-pori kosong pada tanah, sehingga tanah menjadi padat dan dapat meningkatkan daya dukung tanah menjadi lebih baik.Banda Ace
Geostructural and Geomechanical Study of the Piastrone Quarry (Seravezza, Italy) Supported by Photogrammetry to Assess Failure Mode
The use of non-contact-techniques for rock mass characterization has been growing significantly over the last decade. However, their application to stability assessment of ornamental stone has not yet received much attention from researchers. This study utilizes rock mass data both in terms of slope orientations and degree of fracturing obtained from a point cloud, a set of three-dimensional (3D) points representing a rock mass surface, to (1) investigate the influence of geostructures at different scales and (2) assess quarry stability by determining areas susceptible to different failure types. Multi-resolution point clouds are obtained through several photogrammetric survey techniques to identify important structural elements of the site. By integrating orientation data of discontinuity planes, obtained with a traditional survey, and of traces, outlined on point clouds, several joint sets were identified. Kinematic tests revealed various potential failure modes of the rock slope. Moreover, an analysis of the influence of the discontinuity strength determined by the presence of rock bridges was carried out. The study revealed that the strength of the quarry face is governed by the presence of rock bridges that act to improve the stability condition of the rock fronts
ASTRI SST-2M archive system: a prototype for the Cherenkov Telescope Array
The ASTRI project of the Italian National Institute for Astrophysics (INAF) is developing, in the framework of the Cherenkov Telescope Array (CTA), an end-to-end prototype system based on a dual-mirror small-sized Cherenkov telescope. Data preservation and accessibility are guaranteed by means of the ASTRI Archive System (AAS) that is responsible for both the on-site and off-site archiving of all data produced by the different sub- systems of the so-called ASTRI SST-2M prototype. Science, calibration, and Monte Carlo data together with the dedicated Instrument Response Functions (IRFs) (and corresponding metadata) will be properly stored and organized in different branches of the archive. A dedicated technical data archive (TECH archive) will store the engineering and auxiliary data and will be organized under a parallel database system. Through the use of a physical system archive and a few logical user archives that reflect the different archive use-cases, the AAS has been designed to be independent from any specific data model and storage technology. A dedicated framework to access, browse and download the telescope data has been identified within the proposal handling utility that stores and arranges the information of the observational proposals. The development of the whole archive system follows the requirements of the CTA data archive and is currently carried out by the INAF-OAR & ASI-Science Data Center (ASDC) team. The AAS is fully adaptable and ready for the ASTRI mini-array that, formed of at least nine ASTRI SST-2M telescopes, is proposed to be installed at the CTA southern site
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