Search results for " Structural"
showing 10 items of 1751 documents
Aging of MCM41, MSU-H and MSU-F mesoporous systems investigated through the Raman spectroscopy
2014
Here we report an experimental investigation, based on the Raman spectroscopy, on the aging of some mesoporous silica based systems. In details, we studied the aging in air of the MCM41, the MSU-H and the MSU-F materials by acquiring the Raman spectra of as received and of mechanically pressed, at 0.2 and 0.45 GPa, powders. Our data evidenced that the starting powders of the MCM41 and of the MSU-H undergo structural modification when they are exposed to the ambient atmosphere, such modification consisting in the decrease of the D2 Raman band (originated by the three member rings). At variance the powders of the MSU-F appear to be stable. Furthermore, by pressing the starting powders to prod…
Optimal manufacturing and mechanical characterization of high performance biocomposites reinforced by sisal fibers
2018
Abstract The increasing interest about eco-sustainable materials in the industrial production (automotive, civil construction, packaging), has led to the increase of the research works dealing with biocomposites. However, until now the most attention has been devoted to the development of short fiber biocomposites for non-structural applications, whereas only a few works have considered high performance biocomposites for structural applications. Consequently, the development of structural biocomposites from robust natural fibers, as sisal fibers, is a result expected from the scientific community, but not yet achieved. In order to give a contribution to the implementation of high performanc…
An enhanced, near-term HCPB design as driver blanket for the EU DEMO
2019
The Helium Cooled Pebble Bed (HCPB) breeding blanket is a candidate as driver blanket for the EU DEMO. The reference design of the HCPB is based on a cooling plate “sandwich” arrangement built in Multi-Module Segments. This architecture significantly improved the tritium breeding performance (TBR = 1.15) and the plant circulating power (≈130 MW) compared to the former ITER-like “beer-box”-like design (TBR<1.10, plant circulating power>200 MW). However, several issues remain with this design, in which (1) the still large power required per He circulator (beyond the state-of-the-art for these components) and (2) the large tritium inventory foreseen in Be have been identified as the most…
Simplified Procedure to Evaluate Head Losses in Drip Irrigation Laterals
2005
The lateral lines of a drip irrigation system consist of pressurized pipelines with inline or online emitters. Proper hydraulic design of drip laterals usually requires the accurate evaluation of the total head losses, represented by friction losses along the pipe and the emitters, and local losses due to the emitter connections. This paper extends the local loss evaluation procedure, previously obtained for coextruded laterals, on the basis of new experiments. In addition, a simplified procedure was proposed based on the constant outlet discharge assumption for a quick evaluation of total head losses in drip irrigation lines, taking into account the total local loss due to the emitter conn…
Experimental Analysis of Local Pressure Losses for Microirrigation Laterals
2004
The accurate design of drip irrigation laterals needs to consider the variation of hydraulic head due to pipe elevation changes, head losses along the lines, and also, at a given operating pressure, emitter discharge variations related to manufacturing variability, clogging, and water temperature. Hydraulic head variations are consequent to both the friction losses and local losses due to the in-line or on-line emitters along the pipe, which determine the contraction and subsequent enlargement of the flow streamlines. Moreover, in-line emitters usually have a smaller diameter than the pipe, and therefore an additional friction loss must be considered. Evaluation of energy losses and consequ…
Analysis of the steady state hydraulic behaviour of the ITER blanket cooling system
2015
Abstract The blanket system is the ITER reactor component devoted to providing a physical boundary for plasma transients and contributing to thermal and nuclear shielding of vacuum vessel, magnets and external components. It is expected to be subjected to significant heat loads under nominal conditions and its cooling system has to ensure an adequate cooling, preventing any risk of critical heat flux occurrence while complying with pressure drop limits. At the University of Palermo a study has been performed, in cooperation with the ITER Organization, to investigate the steady state hydraulic behaviour of the ITER blanket standard sector cooling system. A theoretical–computational approach …
Liquid metal MHD experimental activities for LLCB TBM development
2013
Abstract In Indian Lead Lithium cooled Ceramic Breeder (LLCB) blanket concept, Lead–Lithium (Pb–Li) liquid metal is used to extract heat from its own bulk volume and also from the neighboring solid breeder zones. The moderate flow velocity of Pb–Li inside the module can be significantly modified due to MHD effects, which arise because of the presence of strong toroidal magnetic field. Recently, two MHD experiments have been jointly carried out at Institute of Physics, University of Latvia (IPUL) with hot Pb–Li (∼350 C) as the working fluid under a strong transverse magnetic field of up to ∼4.0 T. The uncoated test sections are made of SS316L material and consist of LLCB TBM relevant flow ge…
Liquid metal MHD studies with non-magnetic and ferro-magnetic structural material
2014
Abstract In most of the liquid metal MHD experiments reported in the literature to study liquid breeder blanket performance, SS316/SS304 grade steels are used as the structural material which is non-magnetic. On the other hand, the structural material for fusion blanket systems has been proposed to be ferritic martensitic grade steel (FMS) which is ferromagnetic in nature. In the recent experimental campaign, liquid metal MHD experiments have been carried out with two identical test sections: one made of SS316L (non-magnetic) and another with SS430 (ferromagnetic), to compare the effect of structural materials on MHD phenomena for various magnetic fields (up to 4 T). The maximum Hartmann nu…
Numerical and experimental MHD studies of Lead-Lithium liquid metal flows in multichannel test-section at high magnetic fields
2018
Abstract Numerical simulation and experiments have been performed at high magnetic fields (1–3T) to study the MHD assisted molten Lead-Lithium (PbLi) flow in a model test-section which has typical features of multiple parallel channel flows as foreseen in various blanket module of ITER. The characteristics Hartmann number of the presented case study is up to 1557 which is relevant to typical fusion blanket conditions. Symbols B0, a, σ, μ in the definition of Hartmann number are strength of the applied magnetic field, characteristic length scale which is half the channel width parallel to the magnetic field, electrical conductivity and dynamic viscosity of PbLi respectively. Flow distributio…
Chemical compatibility of bulk alumina in flowing PbLi alloy under magnetic field
2021
Abstract Electrically insulating flow channel inserts (FCI) may be needed in liquid-based breeding blanket concepts to electrically decouple the metal flow from the strong magnetic field in a future fusion reactor. Although the magnetohydrodynamic simulation demonstrates a reduction of the pressure drop when a sandwich-like steel-alumina-steel FCI is employed, the tritium production efficiency in the breeding zone of a breeding blanket is limited to 550 °C due to the steel corrosion. Previous theoretical thermomechanical analyses point out the possible occurrence of induced interfacial stresses between the steel and the ceramic part. Both factors motivate the actual FCI development towards …