Search results for "init"
showing 10 items of 6629 documents
Global/Local FEM-BEM stress analysis of damaged aircraft structures
2008
In this paper a Hierarchical approach for the analysis of advanced aerospace structures is presented. The proposed Global/Local model uses two kind of numerical methods. The first step of the Hierarchical procedure is performed by the Finite Element code Patran/Nastran™, using a coarse mesh to study the global structure, then the local region is analyzed by using a Boundary Element code based on the multidomain anisotropic technique. This code accurately predicts stress concentrations at crack tips with a reduction of the modeling efforts and of the computational time. The Global/Local interface code implemented allows an intuitive extraction of the local region with a substantial reduction…
An investigation of thermal behaviour of brake disk pad assembly with Ansys
2021
Abstract The brake disk is a key part of the braking mechanism, the task of it is to slow or stop the vehicle's wheels, on the one side, while the heat produced during the process is dissipated. In this regard, the brake pads are pressed by mechanical strength on the surface of the brake disks. This study aims to develop a model of a disk brake by use of CATIA V5, on the model, finite element analysis (FEA) done by ANSYS 19 then compare it to the findings gained by the original tests. A computational thermo-mechanical study was conducted on this research by use of ANSYS software for disk brake mounting inside a hydraulic brake system. This study is designed to provide insight into the heat …
Use of fiber-section beam elements for modelling the monotonic flexural response of RC jacketed columns
2021
Abstract The use of reinforced concrete (RC) jacketing is a common technique for retrofitting existing RC columns with poor structural performances. Literature studies highlighted that the relative slip occurring at the interface between the new and the old concrete can affect substantially the flexibility and the strength of the retrofitted member. For this reason, several interface treatments are usually applied, aiming to induce a monolithic behaviour to the column. However, despite the commonness of RC jacketing, a limited number of studies investigated numerical modelling strategies for including these phenomena, especially with reference to the development of numerical models for desi…
Nonlinear pressure dependence of the direct band gap in adamantine ordered-vacancy compounds
2010
A strong nonlinear pressure dependence of the optical absorption edge has been measured in defect chalcopyrites CdGa{sub 2}Se{sub 4} and HgGa{sub 2}Se{sub 4}. The behavior is due to the nonlinear pressure dependence of the direct band-gap energy in these compounds as confirmed by ab initio calculations. Our calculations for CdGa{sub 2}Se{sub 4}, HgGa{sub 2}Se{sub 4} and monoclinic {beta}-Ga{sub 2}Se{sub 3} provide evidence that the nonlinear pressure dependence of the direct band-gap energy is a general feature of adamantine ordered-vacancy compounds irrespective of their composition and crystalline structure. The nonlinear behavior is due to a conduction band anticrossing at the {Gamma} po…
Phonon calculations in cubic and tetragonal phases of SrTiO3: A comparative LCAO and plane-wave study
2011
The atomic, electronic structure and phonon frequencies have been calculated in cubic and low-temperature tetragonal SrTiO${}_{3}$ phases at the ab initio level. We demonstrate that the use of the hybrid exchange-correlation PBE0 functional gives the best agreement with experimental data. The results for the standard generalized gradient approximation (PBE) and hybrid PBE0 functionals are compared for the two types of approaches: a linear combination of atomic orbitals (CRYSTAL09 computer code) and plane waves (VASP5.2 code). The relation between cubic and tetragonal phases and the relevant antiferrodistortive phase transition is discussed in terms of group theory and is illustrated with an…
GREEN ENERGY HARVESTING FROM CONCENTRATED SALTWORKS BITTERNS BY REVERSE ELECTRODIALYSIS
2022
Concentrated bitterns discharged from saltworks have extremely high salinity, often up to 300 g/L, thus their direct disposal not only can have harmful effect on the environment, but also generates a depletion of a potential resource of renewable energy. Here, reverse electrodialysis (RED), an emerging electrochemical membrane process, is introduced to capture the salinity gradient power (SGP) intrinsically conveyed by these bitterns also aiming at the reduction of concentrated salty water disposal. A RED unit at the laboratory scale has been adopted to study the SGP potential with different ion exchange membrane and different operating conditions. In particular, membranes supplied by Fujif…
Multiple-scan voltammetry and OCP: Archaeometric tools for dating archaeological bronzes
2021
[EN] The application of a multiple-scan strategy to nanosamples taken from 18 cross-sections of Bronze Age arms and armour, as well as two Roman coins using two solid-state electrochemical techniques, the voltammetry of immobilized microparticles (VIMP) and open circuit potential measurements (OCP) is described. The voltammetric responses in contact with aqueous acetate buffer can be attributed to the reduction of cuprite with variable degree of compaction and crystallinity revealing significant differences in the gradient of such properties with depth. Such differences are also revealed by "dry" OCP measurements connecting points in the cross section near and separated from the corrosion l…
Buckling and nonlinear dynamics of elastically coupled double-beam systems
2016
Abstract This paper deals with damped transverse vibrations of elastically coupled double-beam system under even compressive axial loading. Each beam is assumed to be elastic, extensible and supported at the ends. The related stationary problem is proved to admit both unimodal (only one eigenfunction is involved) and bimodal (two eigenfunctions are involved) buckled solutions, and their number depends on structural parameters and applied axial loads. The occurrence of a so complex structure of the steady states motivates a global analysis of the longtime dynamics. In this regard, we are able to prove the existence of a global regular attractor of solutions. When a finite set of stationary s…
Th17 immunity in children with allergic asthma and rhinitis: a pharmacological approach
2013
Th17 cells and IL-17A play a role in the development and progression of allergic diseases. We analyzed the IL-17A levels in sputum supernatants (Ss), nasal wash (NW) and plasma (P) from Healthy Controls (HC) and children with Asthma/Rhinitis. We tested the expression of IL-17A, RORγ(t) and FOXP3 in peripheral blood T-lymphocytes from intermittent and mild-moderate asthma. The effect of Budesonide and Formoterol was tested "in vitro" on IL-17A, RORγ(t) and FOXP3 expression in cultured T-lymphocytes from mild-moderate asthma/persistent rhinitis patients, and on nasal and bronchial epithelial cells stimulated with NW and Ss from mild-moderate asthma/persistent rhinitis. Further, the effect of …
Development and validation of the neighborhood environment walkability scale for youth across six continents
2019
Abstract Background The IPEN International Physical Activity and Environment Network Adolescent project was conducted using common study protocols to document the strength, shape, and generalizability of associations of perceived neighborhood environment attributes with adolescents’ physical activity and overweight/obesity using data from 15 countries. Countries did not use identical versions of the Neighborhood Environment Walkability Scale for Youth (NEWS-Y) to measure perceived neighborhood environment attributes. Therefore, this study derived a measurement model for NEWS-Y items common to all IPEN Adolescent countries and developed a scoring protocol for the IPEN Adolescent version of t…