Search results for "visual_art"
showing 10 items of 2987 documents
A simplified predictive approach to assess the mechanical behavior of pinned hybrid composites aged in salt-fog environment
2020
Abstract Aim of this paper is to assess the predictive capabilities of a simplified theoretical approach on the failure load of aged pinned hybrid composites. In particular, the mechanical performances of glass-flax hybrid epoxy laminates exposed to salt spray fog environment, were used as input data in order to address the analytical model. Preliminarily, the relationship among mechanical performances, failure mechanisms, joint geometry and ageing time, was evaluated by double-lap joint tests on pinned samples at varying joint geometry and ageing time. The bearing and shear out limit stress of samples aged for 60 days under the salt-fog environment underwent a reduction of about 20% compar…
Effect of curing time on the performances of hybrid/mixed joints
2013
Abstract The aim of this work is the study of a mixed method used for the joining of aluminum alloys with glass reinforced polymer’s substrates (in the next GFRP). In particular, the technique of self-piercing riveting (in the next SPR) was applied on a co-cured joint in order to evaluate the influence of the time of inserting the rivet on the mechanical behavior of the mixed joints. Three different joints were realized: adhesive by co-curing technique, mechanical by self piercing riveting (in the next SPR) and a mixed one in which the joining techniques (i.e. adhesive and mechanical) were combined. In particular, to determine the optimum time to insert the rivet, three different times from…
Solution precursor plasma spray process as an alternative rapid one-step route for the development of hierarchical ZnO films for improved photocataly…
2018
Abstract The development of efficient photocatalytic hierarchical coral-like ZnO films via a relatively simple, efficient, rapid and single-step process is essential for industrial development. Herein, we report a novel method for directly synthesizing well-shaped ZnO nanorods (NRs) by Solution Precursor Plasma Spray (SPPS) process rather than conventional spherical/ellipsoidal particles. In the prepared ZnO-NRs films, the ZnO NRs display an average diameter of 190 nm, and exhibit a preferential orientation growth along (002) plane compared to a reference ZnO films (called ZnO-P) containing spherical/ellipsoidal particles. ZnO-NRs films exhibit relative narrower bandgap (3.02 eV) probably d…
Electrochemical Investigation of Hydrogen Evolution and Absorption Phenomena in Nickel Based Electrodes
1996
Due to its potential for industrial applications, hydrogen absorption in metals has attracted continuous interest. Understanding the hydrogen chemistry in metals is crucial due to the significance of hydrogen-metal interactions in important industrial and technical applications such as catalysis, H-fuel containment, corrosion and embrittlement of metals and rechargeable metal hydride batteries [1–2].
Substrate templating upon self-assembly of hydrogen-bonded molecular networks on an insulating surface.
2012
M olecular self-assembly on insulating surfaces, despite being highly relvant to many applications, generally suffers from the weak molecule–surface interactions present on dielectric surfaces, especially when benchmarked against metallic substrates. Therefore, to fully exploit the potential of molecular self-assembly, increasing the infl uence of the substrate constitutes an essential prerequisite. Upon deposition of terephthalic acid and trimesic acid onto the natural cleavage plane of calcite, extended hydrogen-bonded networks are formed, which wet the substrate. The observed structural complexity matches the variety realized on metal surfaces. A detailed analysis of the molecular struct…
Influence of the external stretching on hydrogen electromigration in palladium
2002
Abstract Electromigration and diffusion of hydrogen in palladium depending on unit elongation were investigated. It was found that the obtained experimental results cannot be described by means of a single flux of hydrogen, which diffuses in a gradient of electric field. In order to effectively explain the obtained results, a theoretical model was elaborated. It assumed the existence of the following two fluxes of hydrogen in the stretched metal: • Ji—of migration, according to the interstitial mechanism, and • Ji-d—of migration, according to the interstitial-defective mechanism. Dependence of effective valences and diffusion coefficients for both mechanisms of transportation were determine…
Iridium metal and iridium oxide thin films grown by atomic layer deposition at low temperatures
2011
Atomic layer deposition (ALD) of both iridium and iridium oxide films at low temperatures has been studied and the resulting films have been examined by XRD, FESEM, XRR, EDX, AFM, TOF-ERDA, and four point probe measurements. Iridium oxide films were successfully grown using (MeCp)Ir(CHD) and ozone between 100 and 180 °C, however, the density of the films substantially reduced at 120 °C and below. The density reduction was accompanied by a phase change from crystalline to amorphous IrO2. Metallic iridium films were deposited between 120 and 180 °C by adding a reductive hydrogen pulse after the oxidative ozone pulse. Comparison of these processes with the earlier process employing the same Ir…
Dual Ni/Ni-Co electrodeposited coatings for improved erosion-corrosion behaviour
2019
Abstract Industrial applications of hydrophobic metallic coatings are limited to durability of their surface structures against detrimental effects of the surrounding environments. In the present research, the life-long of the hierarchical structure of hydrophobic nickel coating in an erosive-corrosive solution was investigated. The effect of alloying with cobalt on strengthening the hierarchical structures was also investigated. In this regard, highly hydrophobic Ni/Ni, Ni-Co/Ni-Co, dual Ni/Ni-Co and dual Ni-Co/Ni coatings with rough hierarchical structures were electrodeposited. In situ electrochemical measurements were performed to investigate changes in corrosion resistance and hydropho…
The effect of combining laser and nanohydroxy-apatite on the surface properties of enamel with initial defects
2017
Background The aim of this study was to evaluate the effect of combining fractional CO2 LASER and nanohydroxy apatite on surface microhardness and color of enamel with initial defects. Material and Methods Two types of nano hydroxylapatite (nHAP) was prepared; Pure hydroxyapatite (nHA) and Fluoro hydroxyapatite (nFHA), Sixty extracted premolar teeth without visible caries or structural defects on enamel surface were used, immersed in 10 ml of a demineralizing solution for 2 weeks to create artificial white spot lesions, they were randomly allocated into two groups; Group 1: nHA, Group 2: nFHA, each group is then subdivided into 2 subgroups (A and B) where two different in vitroremineralizat…
Synthesis highly active platinum tri-metallic electrocatalysts using "one-step" organometallic chemical vapour deposition technique for methanol oxid…
2012
A simple solvent free method for the synthesis of tri-metallic platinum electrocatalysts on carbon nanotubes is presented. By investigating the platinum alloy electrocatalysts, it was showed that the additional metals of platinum alloys could reduce the metal particle sizes and produce larger chemical-active surface area, as well as the higher methanol oxidation activity of the catalysts. The organometallic chemical vapour deposition method was successfully applied to produce multiple samples of PtRuFe, PtRuCu and PtRuV. The electrocatalysts were characterized by ICP, XRD, HRTEM and the catalytic activity was determined by cyclic voltammetry (CV).