Search results for "INTERFACE"
showing 10 items of 2139 documents
Barriers and paradoxical recommendation behaviour in online to offline (O2O) services. A convergent mixed-method study
2021
Mobile apps offering online to offline (O2O) services act as aggregators providing interface for delivery of required products and services at a preferred location. Despite offering multiple affordances, many O2O services have not diffused as anticipated, indicating the existence of consumer resistance towards them. One such example is that of food delivery apps (FDAs), which are experiencing resistance at both the pre-adoption and post-adoption stage. However, there are scarce empirical findings explicating the pre-and post-adoption barriers perceived to be associated with FDAs. The present study addresses this gap by utilising the Innovation Resistance Theory (IRT) and a convergent mixed-…
Characterization and properties of PEO coatings on 7075 Al alloy grown in alkaline silicate electrolyte containing KMnO 4 additive
2017
Abstract Plasma electrolytic oxidation (PEO) was used to modify the surface of 7075 Al alloy by applying a bipolar pulsed-current in a silicate based electrolyte containing 0 to 3 g L− 1 KMnO4. For the coating produced in the base electrolyte, crystalline γ-Al2O3 was the main phase, while the coatings formed at the presence of KMnO4 consisted of α-Mn2O3 containing Si and Al oxides. A pancake structure was observed on surface of the coating produced in the base electrolyte, while a foam feature along with some volcano-like areas was detected on the surface of the coatings produced in the presence of KMnO4. The KMnO4 changed the discharge type leading to diminish the pores at the metal/coatin…
Anodizing of aluminium and AA 2024-T3 alloy in chromic acid: Effects of sulphate on film growth
2017
Chromic acid anodizing is important for the corrosion protection of aerospace aluminium alloys. Previous study has demonstrated that SO42 − impurity in the chromic acid affects the film growth on aluminium at a voltage of 100 V. The present work further investigates aluminium and extends the study to industrial anodizing conditions (Bengough-Stuart (B-S) process) and to the AA 2024-T3 alloy. It is shown that SO42 − concentrations between ~ 38–300 ppm reduce the film growth rate for aluminium anodized at 100 V in comparison with an electrolyte than contains ≤ 1.5 ppm SO42 −, whereas ~ 1500–3000 ppm SO42 have an opposite effect and lead to an unstable pore diameter. Under the B-S process, the…
Influence of post-treatment time of trivalent chromium protection coating on aluminium alloy 2024-T3 on improved corrosion resistance
2019
Abstract Low corrosion protection performances of Trivalent Chromium Process (TCP) coatings with reference to Chromium Conversion Coatings (CCC) deposited on aluminium alloys can be overcome by application of post-treatment processes. This work shows the effect of post-treatment bath (containing hydrogen peroxide and lanthanum salt) on the chemical composition, structure and the corrosion performances of TCP coating deposited on AA 2024-T3 aluminium alloy. Different times of post-treatment bath were applied on the TCP coating and the samples were analyzed by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and Glow Discharge-Optical Emission …
Metallic interconnects for SOFC : characterization of their corrosion resistance in hydrogen/water atmosphere and at the operating temperatures of di…
2006
International audience; Chromia forming alloys are one of the best candidates for the interconnecting materials in solid oxide fuels cells (SOFC). Recent research has enabled to decrease the operating temperature of the SOFC from 1000 °C to 800 °C. However, low electronic conductivity and high volatility of the chromia scale need to be solved to improve performance of interconnects. In the field of high temperature oxidation of metals, it is well known that the addition of reactive elements into alloys or in thin film coatings, improve the oxidation resistance of alloys at high temperature. The elements of the beginning of the lanthanide group and yttrium are the most efficient. The goal of…
Static strength and fatigue life of optimized hybrid single lap aluminum–CFRP structural joints
2017
Hybrid bolted/bonded joints are used to assemble structural components, commonly made by carbon fiber reinforced plastics (CFRP), with aluminum frames. Hence, they have become common solutions in a number of modern structural applications in the industrial fields, as well as civil constructions. Unfortunately, due to the lack of understanding of the relationships between the multiple parameters of influence that characterize their mechanical performance, only limited improvement have been achieved so far over classical bonding approaches, in terms of static and fatigue strength. As a result, further studies are needed in order to better exploit the potential of hybrid bolted/bonded joints a…
The corrosion and tribocorrosion resistance of PEO composite coatings containing α-Al2O3 particles on 7075 Al alloy
2018
Abstract Plasma electrolytic oxidation (PEO) of 7075 Al alloy was carried out in silicate base electrolyte containing 200 nm diameter α-Al2O3 particles for producing composite coatings. The process was performed under a soft-sparking regime using a pulsed bipolar signal with several concentrations of α-Al2O3 particles. It was found that the incorporation of α-Al2O3 particles into the coating did not significantly alter the thickness and roughness of the coating. However, the α-Al2O3 particles were detected on surface of the composite coatings. Corrosion tests showed significant improvement in corrosion performance of the composite coatings due to the efficient pore blocking provided by α-Al…
Amorphous hydrogenated carbon (a-C:H) depositions on polyoxymethylene: Substrate influence on the characteristics of the developing coatings
2016
Abstract After oxygen plasma treatment polyoxymethylene (POM) material was exposed to acetylene plasma to progressively deposit two different types of amorphous hydrogenated carbon (a-C:H) films. Radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) was used to generate both plasma processes. The surface morphology of the coated samples has been investigated by atomic force microscopy (AFM) and their chemical composition by Diffusive Reflectance Infrared Fourier Transform (DRIFT) and Raman spectroscopy. Results revealed the absence of a solid interlayer formation between the a-C:H films and POM. The in sequence exposure of oxygen and acetylene plasma on POM substrate prevents…
Organic-inorganic nanocomposites prepared by reactive suspension method: investigation on filler/matrix interactions and their effect on the nanopart…
2017
Epoxy resin/TiO2 nanocomposites prepared by both reactive suspension method, based on in situ synthesis, and conventional mechanical mixing are analysed by solid-state nuclear magnetic resonance and transmission electron microscopy in order to have a deeper insight into the nature of interactions at the polymer/particle interface and their effect on the nanoparticles dispersion. Specifically, solid-state nuclear magnetic resonance experiments showed that the nanoparticles, synthesized by reactive suspension method, can efficiently link the matrix by hydrogen bonds forming a hybrid organic-inorganic 3D network. Such evidences strongly supports our previously reported theory, in which the nan…
Nanoemulsions for synthesis of biomedical nanocarriers
2021
Nanoemulsions are kinetically stabilized emulsions with droplet sizes in the nanometer scale. These nanodroplets are able to confine spaces in which reactions of polymerization or precipitation can take place, leading to the formation of particles and capsules that can act as nanocarriers for biomedical applications. This review discusses the different possibilities of using nanoemulsions for preparing biomedical nanocarriers. According to the chemical nature, nanocarriers prepared in nanoemulsions are classified in polymeric, inorganic, or hybrid. The main synthetic strategies for each type are revised, including miniemulsion polymerization, nanoemulsion-solvent evaporation, spontaneous em…