1,204 research outputs found
Digital Recording of Historical Defensive Structures in Mountainous Areas Using Drones: Considerations and Comparisons
Digital recording of historic buildings and sites in mountainous areas could be challenging. The paper considers and discusses the case of historical defensive structures in the Italian Alps, designed and built to be not accessible. Drone images and photogrammetric techniques for 3D modeling play a fundamental role in the digital documentation of fortified constructions with non-contact techniques. This manuscript describes the use of drones for reconstructing the external surfaces of some fortified structures using traditional photogrammetric/SfM solutions and novel methods based on NeRFs. The case of direct orientation based on PPK and traditional GCPs placed on the ground is also discussed, considering the difficulties in placing and measuring control points in such environments
Zystoskopie bei einem Rind mit Urachus persistens-Ruptur
Die Arbeit beschreibt die klinischen, sonographischen und zystoskopischen Befunde sowie die Therapie bei einem 2-jährigen, 7 Monate trächtigen Braunviehrind mit Ruptur des Urachus persistens. Das Leitsymptom war ein birnförmiges Abdomen bei stark gestörtem Allgemeinbefinden. Die Blutuntersuchung ergab eine hochgradige Azotämie. Bei der Ultraschalluntersuchung wurde ein Aszites festgestellt, welcher aufgrund der massiv erhöhten Kreatininkonzentration im Punktat als Uroperitoneum klassiert wurde. Bei der Zystoskopie konnte das Endoskop über die Harnblase in einen persistierenden Urachus eingeführt werden. Aufgrund sämtlicher Befunde wurde die Diagnose Uroperitoneum infolge Ruptur eines Urachus persistens gestellt. Als Therapie wurde eine Laparotomie in der linken Flanke mit doppelter Ligation des Urachus durchgeführt. Innerhalb von wenigen Tagen normalisierte sich der Zustand des Rindes. Es hat inzwischen normal gekalbt und erfreut sich bester Gesundheit
This case report describes the clinical, ultrasonographic and cystoscopic findings and treatment in a two-year-old Swiss Braunvieh heifer with rupture of a patent urachus. The lead signs in the seven-month-pregnant heifer were markedly abnormal general condition and demeanour and a pear-shaped abdomen. The heifer had severe azotaemia, and abdominal ultrasonography revealed ascites, which was diagnosed as uroperitoneum based on an elevated creatinine level in the fluid. A patent urachus was identified during cystoscopy; the endoscope could be advanced beyond the apex of the urinary bladder into the urachus. Based on all the findings, a diagnosis of uroperitoneum attributable to rupture of a patent urachus was made. The urachus was ligated twice via a left-flank laparotomy. The general condition normalised within a few days of surgery, and the patient calved normally and was in good health at follow-up evaluation
Scintillating double beta decay bolometers
We present the results obtained in the development of scintillating Double
Beta Decay bolometers. Several Mo and Cd based crystals were tested with the
bolometric technique. The scintillation light was measured through a second
independent bolometer. A 140 g CdWO_4 crystal was run in a 417 h live time
measurement. Thanks to the scintillation light, the alpha background is easily
discriminated resulting in zero counts above the 2615 keV gamma line of
Thallium 208. These results, combined with an extremely easy light detector
operation, represent the first tangible proof demonstrating the feasibility of
this kind of technique.Comment: 15 pages, 8 figure
Electrochemistry of cyclic triimidazoles and their halo derivatives: A casebook for multiple equivalent centers and electrocatalysis
A family of cyclic triazines, based on the triimidazo[1,2-a:1\u2032,2\u2032-c:1\u2033,2\u2033-e][1,3,5]triazine scaffold, has recently caught attention due to its variegated solid state photoluminescent properties (e.g., crystallization induced emission, fluomechanochromism, dual fluorescence, room temperature ultralong phosphorescence), tuned by proper functionalization of the cyclic core. From an electrochemical point of view, this family of heteroaromatic cyclic triazines is unexplored. A cyclic voltammetry study is here performed aiming to clarify structure/electroactivity relationship. The peculiar molecular structure of this class of molecules offers a multi-approach case study, spanning from multiple equivalent redox site interactions in small hoops (due to ideally C3h symmetry) to carbon-halogen bond reactivity in the presence of catalytic metal electrode surfaces (for \u2013Br and \u2013I derivatives). Results point to a poor heteroannular aromaticity along the rigid, planar cyclotrimer, with each equivalent redox site acting quite independently. An unusually higher electrocatalytic performance of gold with respect to silver electrode for the electrocleavage of carbon-halogen bonds (that decreases by increasing number of halo substituents) is tentatively explained in term of a specific interaction between gold and the nitrogen-rich planar cyclotrimer platform
The 4 K outer cryostat for the CUORE experiment: construction and quality control
The external shell of the CUORE cryostat is a large cryogen-free system
designed to host the dilution refrigerator and the bolometers of the CUORE
experiment in a low radioactivity environment. The three vessels that form the
outer shell were produced and delivered to the Gran Sasso underground
Laboratories in July 2012. In this paper, we describe the production techniques
and the validation tests done at the production site in 2012.Comment: 11 pages, 13 figures; to appear in NIM
The safety assessment of Campotosto Lake dams following 2016-2017 seismic sequence in Central Italy. Focus on Poggio Cancelli embankment dam
The Campotosto Lake is one of the biggest reservoirs of Europe, with a storage capacity exceeding
200 million of m3. The natural original lake was confined with three large dams owned by
Enel.
In the recent past, the lake and the dams have been subjected to a series of seismic events
known as the seismic sequence of L'Aquila in 2009 and the seismic sequence of Central Italy in
2016-17. Following the last one, Enel promptly decided to temporarily lower the water level to
carry out surveys, measurements and automatic monitoring activities. Based on available data, in
order to verify, ensure and asseverate the safety conditions of the dams and the lake’s slopes, a
series of multi-disciplinary studies and in-depth analysis were specifically conducted.
Detailed studies were developed for the Poggio Cancelli embankment dam: geotechnical surveys,
geophysical in situ tests and “advanced” laboratory tests in order to define at best the foundation
soil characteristics, thus reasonably excluding the liquefaction risk applying sophisticated
methods of analysis. Moreover, InSAR analysis allowed to retrieve the displacement history of
the sites and confirmed the topographic measurements taken before and after the earthquakes.
Displacement data, together with the real accelerograms recorded at the dam toe were used for a
back analysis of the settlements by means of a FEM model of the dam. With this validated model,
it was possible to simulate the seismic response of the embankment in the catastrophic scenario
represented by the worst expected earthquake at the site. However, recent and important research
contributed to establish the position and associated potential magnitude of the Campotosto fault.
They indicate that the seismic scenario adopted by our analysis is precautionary, therefore our
results are conservative.
Seismic assessments on the other dams and InSAR analysis of the slopes surrounding the reservoir
were also carried out.
All these studies were concluded in 2020 showing good results and satisfactory safety factors,
allowing Enel to set up again Campotosto reservoir to normal water levels
Hybrid manufacturing of steel construction parts via arc welding of LPBF-produced and hot-rolled stainless steels
The demand for free-form steel structures having improved performances, reducing labour and resource usage is increasing in the construction sector. Structural nodes are some of the most critical regions for steel structures characterised often by large dimensions. These nodes can exploit the geometrical freedom of metal additive manufacturing (MAM) processes. Laser powder bed fusion (LPBF) is arguably the most developed MAM process, which has limitations regarding the size of the parts to be produced. A way to overcome the size limits of LPBF for producing structural nodes while still exploiting its geometrical capacity is producing hybrid components by welding them to traditionally manufactured beams. Such hybrid joints would constitute a complex system from a mechanical design perspective requiring a systematic analysis in order to be certified for structural use. Accordingly, this work studies the mechanical behaviour of hybrid steel components generated by welding LPBF plates and quarto plates made of AISI 316L stainless steel. The work was guided by a case study based on a large steel node, which helped defining the requirements to fill the gap of the international standards. The mechanical characterisation of LPBF-produced plates and quarto plates, as well as the welded hybrid components revealed a maximum of 10% difference between the properties of the differently manufactured plates. Through the digital image correlation (DIC) analyses, the anisotropic deformation behaviour along the LPBF, weld seam, and quarto plate regions have been identified, and the properties after welding did not show relevant modifications. The tests allowed to define that the failure behaviour is mainly governed by interlayer bounds, and a 0.9 safety reduction parameter for considering the reduction of ductility induced by arc welding to LPBF. Finally, design and production suggestions have been provided for a correct evaluation of gross and effective sections of the designed nodes
A bolometric measurement of the antineutrino mass
High statistics calorimetric measurements of the beta spectrum of 187Re are
being performed with arrays of silver perrhenate crystals operated at low
temperature. After a modification of the experimental set-up, which allowed to
substantially reduce the background of spurious counts and therefore to
increase the sensitivity on the electron antineutrino mass, a new measurement
with 10 silver perrhenate microbolometers is running since July 2002. The
crystals have masses between 250 and 350 micrograms and their average FWHM
energy resolution, constantly monitored by means of fluorescence X-rays, is of
28.3 eV at the beta end-point. The Kurie plot collected during 4485 hours x mg
effective running time has an end-point energy of 2466.1 +/- 0.8{stat} +/- 1.5
{syst} eV, while the half lifetime of the decay is found to be 43.2 +/-
0.2{stat} +/- 0.1{syst} Gy. These values are the most precise obtained so far
for 187Re. From the fit of the Kurie plot we can deduce a value for the squared
electron antineutrino mass m(nu)^2 of 147 +/- 237{stat} +/- 90{syst} eV^2. The
corresponding 90% C.L. upper limit for m(nu) is 21.7 eV.Comment: 3 pages, 3 figures. Submitted to Phys. Rev. Let
Electromagnetic shielding properties of LPBF produced Fe2.9wt.%Si alloy
Ferromagnetic materials are used in various applications such as rotating electrical machines, wind turbines, electromagnetic shielding, transformers, and electromagnets. Compared to hard magnetic materials, their hysteresis cycles are featured by low values of coercive magnetic field and high permeability. The application of additive manufacturing to ferromagnetic materials is gaining more and more attraction. Indeed, thanks to a wider geometrical freedom, new topological optimized shapes for stator/rotor shapes can be addressed to enhance electric machines performances. However, the properties of the laser powder bed fusion (LPBF) processed alloy compared to conventionally produced counterpart must be still addressed. Accordingly, this paper presents for the first time the use of the LPBF for the manufacturing of Fe2.9wt.%Si electromagnetic shields. The process parameter selection material microstructure and the magnetic shielding factor are characterized
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