Search results for "Mechanics of Materials"
showing 10 items of 2598 documents
Study of phase transition in Bi3TiNbO9-BaBi2Nb2O9 ceramics
2016
Abstract The subject of the paper is lead free bismuth layer structure oxides (1-x)Bi3TiNbO9-xBaBi2Nb2O9 (x=0; 1; 2; 3 mol). The influence of Bi3TiNbO9/BaBi2Nb2O9 ratio on dielectric and structural properties was studied in a wide range of temperatures. Change in the ratio causes a decrease in the maximum value of dielectric permittivity and shifts the temperature of ε’max to low values, leading to linear decreasing of average grain size and linear increasing of ceramics density. These results indicate an augment of the packing degree and the participation of pores are significantly decreased with the increase of BaBi2Nb2O9 compound intake. Moreover, for 0.7Bi3TiNbO9-0.3BaBi2Nb2O9 ceramics …
Modeling bismuth insertion in 1D hybrid lead halide TMSO(Pb x Bi y )I3 pseudo-perovskites
2022
Abstract The structures of the disordered 1D (pseudo-)perovskites of general TMSO(Pb x Bi y )I3 formulation [TMSO = (CH3)3SO+], obtained by doping the TMSOPbI3 species with Bi3+ ions, are investigated through the formulation of a statistical model of correlated disorder, which addresses the sequences of differently occupied BI6 face-sharing octahedra (B = Pb, Bi or vacant site) within ideally infinite [(BI3)−] n chains. The x-ray diffraction patterns simulated on the basis of the model are matched to the experimental traces, which show many broad peaks with awkward (nearly trapezoidal) shapes, under the assumption that the charge balance is fully accomplished within each chain. The analysis…
On the limit velocity and buckling phenomena of axially moving orthotropic membranes and plates
2011
In this paper, we consider the static stability problems of axially moving orthotropic membranes and plates. The study is motivated by paper production processes, as paper has a fiber structure which can be described as orthotropic on the macroscopic level. The moving web is modeled as an axially moving orthotropic plate. The original dynamic plate problem is reduced to a two-dimensional spectral problem for static stability analysis, and solved using analytical techniques. As a result, the minimal eigenvalue and the corresponding buckling mode are found. It is observed that the buckling mode has a shape localized in the regions close to the free boundaries. The localization effect is demon…
Flash infrared annealing as a cost-effective and low environmental impact processing method for planar perovskite solar cells
2019
Abstract For successful commercialization of perovskite solar cells, straightforward solutions in terms of environmental impact and economic feasibility are still required. Flash Infrared Annealing (FIRA) is a rapid method to fabricate perovskite solar cells with efficiencies >18% on simple, planar architecture, which allows a film synthesis in only 1.2 s, faster than the previous report based in a meso architecture and all of them without the usage of antisolvent. In this work, through a comparative study with the common lab-scale method, the so-called antisolvent (AS), the main photovoltaic parameters and working mechanisms obtained from impedance spectroscopy (IS) measurements show simil…
Analytical and finite element analyses on reliability of carbon fibre reinforced plastics
2013
International audience
Analysis of the effects of magnetic field on the induced stress in drilled plates
2013
Abstract A drilled plate of ferromagnetic material suitably coupled by coils of enameled copper wire fed by a DC power supply to 30 V is considered in this paper. It is analyzed with finite element and later experiments are performed to validate the obtained results. After polishing the plate, two strain gauges for measuring the deformation along the x axis and along the z axis are installed. The values of strain are 5 μm/m in z direction and −2 μm/m in x direction. The experimental–numerical comparison shows that the laboratory results are lower than numerical, while signs and orders of magnitude are the same. It is concluded that the results of the FEM analysis can be considered acceptabl…
High content and dispersion of Gd in bimodal porous silica: T2 contrast agents under ultra-high magnetic fields
2022
Silica-based UVM-7-type bimodal mesoporous materials with high gadolinium content (∞ ≥ Si/Gd ≥ 13) have been synthesized through a one-pot surfactant-assisted procedure from hydroalcoholic solution using a cationic surfactant as template, and starting from atrane complexes of Gd and Si as inorganic precursors. The novel synthetic pathway developed in the study preserves the UVM-7-type architecture while optimizing the dispersion of the Gd-guest species at the nanoscale and even at atomic level. It has been determined that the number of Gd atoms forming clusters is always less than 10. The behaviour under exposure to ultra-high magnetic fields reveals a significant increase in the transversa…
Random vibration mitigation of beams via tuned mass dampers with spring inertia effects
2019
The dynamics of beams equipped with tuned mass dampers is of considerable interest in engineering applications. Here, the purpose is to introduce a comprehensive framework to address the stochastic response of the system under stationary and non-stationary loads, considering inertia effects along the spring of every tuned mass damper applied to the beam. For this, the key step is to show that a tuned mass damper with spring inertia effects can be reverted to an equivalent external support, whose reaction force on the beam depends only on the deflection of the attachment point. On this basis, a generalized function approach provides closed analytical expressions for frequency and impulse res…
New hydrogel matrices containing an anti-inflammatory agent. Evaluation of in vitro release and photoprotective activity.
2002
In the present work. the preparation and characterization of hydrogels based on alpha,beta-polyaspartylhydrazide (PAHy) chemically crosslinked with ethyleneglycol diglycidylether (EGDGE) containing Tolmetin sodium salt, are reported. In particular, these samples have been prepared both as water swellable microparticles and as gels at two different crosslinking degrees. The incorporation of Tolmetin sodium salt in PAHy-EGDGE microparticles has been performed after the crosslinking reaction by a soaking procedure or during the formation of the network. The influence of drug loading procedure on Tolmetin release has been evaluated by performing in vitro release study in simulated gastrointesti…
Materials for Respiratory Masks in the Context of COVID 19 Pandemic
2021
In the context of the COVID-19 pandemic and the lack of protective equipment worldwide, we aimed to study the literature for finding guidelines in the 3D manufacture of respiratory masks. We have searched for papers in CI-EXPANDED, SSCI, A&HCI, CPCI-S, CPCI-SSH, BKCI-S, BKCI-SSH, ESCI, CCR-EXPANDED, IC, using 3D printing materials sterilization and 3D printing materials disinfection keywords. From 80 results in databases, after refining, we selected six papers. We have also searched for manufacturers information regarding 3D printing materials sterilization or disinfection. We have found seven materials that are suitable for 3D printing and sterilization, with regards to multiple utili…