Search results for " Structural"
showing 10 items of 1751 documents
Compatibility, effectiveness and susceptibility to degradation of alkoxysilane-based consolidation treatments on a carbonate stone
2021
Abstract Alkoxysilane-based consolidation treatment are commonly employed in restoration and conservation works of Cultural Heritage buildings. However, their poor affinity to carbonate stones is well-known. In this paper, we evaluate three consolidant treatments (two of them modified to incorporate hydrophobic or photocatalytic properties), formulated to circumvent this drawback and their cracking during drying, through a surfactant-assisted synthesis. The consolidants were applied on Noto stone, a biocalcarenite (~95% CaCO3 ) employed in numerous Cultural Heritage buildings of Southern Italy. A comprehensive validation of the three consolidants, compared to a commercial TEOS based consoli…
Self-similarity and response of fractional differential equations under white noise input
2022
Self-similarity, fractal behaviour and long-range dependence are observed in various branches of physical, biological, geological, socioeconomics and mechanical systems. Self-similarity, also termed self-affinity, is a concept that links the properties of a phenomenon at a certain scale with the same properties at different time scales as it happens in fractal geometry. The fractional Brownian motion (fBm), i.e. the Riemann-Liouville fractional integral of the Gaussian white noise, is self-similar; in fact by changing the temporal scale t -> at (a > 0), the statistics in the new time axis (at) remain proportional to those calculated in the previous axis (t). The proportionality coeffi…
Spatial Reconstruction Algorithm of DT Layer in Cryogenic Targets Using Optical Techniques
2007
The measurements of the solid DT layer, in terms of thickness and roughness, in the LMJ geometry (i.e. in a hohlraum) are not trivial. The DT layer measurements will be done using a Matsukov-Cassegrain telescope placed 39 cm away from the target. This telescope will be used to acquire shadowgraphy images on equators, and interferometric measurements on pole areas using optical coherence tomography (OCT). Optical coherence tomography allows determining the DT layer thickness on a few points, in the polar regions of the target. By scanning around the poles, several points can be acquired in order to calculate the roughness and the local shape of the DT layer at the pole. Both techniques were …
Advancements in the Helium-Cooled Pebble Bed Breeding Blanket for the EU DEMO: Holistic Design Approach and Lessons Learned
2019
The helium-cooled pebble bed (HCPB) blanket is one of the two concepts proposed as a driver blanket for the European Union Demonstration Fusion Power Reactor (EU DEMO). In contrast to past conceptual design studies, in the frame of the current Power Plant Physics and Technology of the EUROfusion Consortium, the ongoing EU DEMO preconceptual design activities have adopted a holistic and integrated (i.e., systems engineering) design approach. As a consequence of this new approach, many interfaces and requirements have been identified, some of them driving the design of the blankets. This paper shows the advancements in the HCPB breeding blanket and describes the lessons learned after implemen…
TRITIUM RELEASE CHARACTERISTICS OF NEUTRON-IRRADIATED REFERENCE BERYLLIUM PEBBLES FOR THE HELIUM COOLED PEBBLE BED (HCPB) BLANKET
2011
In this paper, we present results on tritium release from the beryllium pebbles irradiated for 294 full power days from 17 April 2003 to November 2004 to the neutron fluence of 1.5-2 × 1025 m-2 (E>...
Germanium Doped CHxMicroshells for LMJ Targets
2011
AbstractAt the CEA Laser “Megajoule” facility, amorphous hydrogenated carbon (a-C:H or CHx) is the nominal ablator used to achieve inertial confinement fusion experiments. These targets are filled with a fusible mixture of deuterium-tritium in order to perform ignition.Since the achievement of ignition greatly depends on the physical properties of the shell, there must be precise control of thicknesses, doping concentration, and roughness. Experimental devices associated with suitable characterizations are described in this paper. The tolerances and yields for each specification are also presented. Some specifications are largely reached; high-frequency surface roughness due to isolated sur…
A Model to Characterize the D-T Layer of ICF Targets by Backlit Optical Shadowgraphy
2005
A numerical model is presented in order to modelize the bright ring that appears in backlit optical shadowgraphy on a transparent hollow sphere with a solid deuterium-tritium layer inside. This novel model is based on computational calculations applied to the problem of the targets used in inertial confinement fusion. The model takes into account the influences of the optical imaging system (numerical aperture, source divergence, camera resolution, etc.) and the effect of the capsule itself, diameter, thickness, and refractive index, and allows one to analyze the inner surface of a capsule in terms of thickness and roughness.
Phenomenological Model for Gold-Copper Electrodeposition: Application to Thick Coatings
2016
Pure gold-copper alloys are known to be difficult to electrodeposit because of a strong variation in composition after a few microns have been deposited. Commissariat al’Energie Atomique (CEA) stud...
Hydraulic analysis of EU-DEMO divertor plasma facing components cooling circuit under nominal operating scenarios
2019
Within the framework of the Work Package DIV 1 – “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by University of Palermo and ENEA to investigate the steady state thermal-hydraulic behaviour of the DEMO divertor cassette cooling circuit, focussing the attention on its Plasma Facing Components (PFCs). The research campaign has been carried out following a theoretical-computational approach based on the Finite Volume Method and adopting the commercial Computational Fluid-Dynamic code ANSYS-CFX. A realistic model of the PFCs cooling circuit has been analysed, specifically embedding each Plasma Facing Unit (PFU) cooling chann…
Conceptual design of the main Ancillary Systems of the ITER Water Cooled Lithium Lead Test Blanket System
2021
Abstract The Water Cooled Lithium Lead Test Blanket System (WCLL TBS) is one of the EU Test Blanket Systems candidate for being installed and operated in ITER. In view of its Conceptual Design Review by F4E and ITER Organization (IO), planned for mid-September 2020, several technical activities have been performed in the areas of WCLL TBS Ancillary Systems design. In this article the outcomes of the conceptual design phase of the four main Ancillary Systems of WCLL TBS, namely the Water Cooling System (WCS), the Coolant Purification System (CPS), the PbLi loop and the Tritium Extraction System (TES), are reported and critically discussed. In particular, for each Ancillary System hereafter a…