A Study on the Effect of Laser Surface Texturing on Friction and Wear Behavior of Graphite Cast Iron

Dimples with various pitches and densities were produced using laser surface texturing (LST) to improve the friction and wear behavior of graphite cast iron. The objective of this study is to investigate the effectiveness of dimples on the friction and wear behavior of an internal combustion engine (ICE) cylinder. The specimens with a dimple pitch of 150 lm and a dimple density of 13% exhibited the lowest friction coefficient among the specimens, while the specimens with a dimple pitch of 200 lm and a density of 7% exhibited the highest resistance to wear

Antifungal Nanocomposites Inspired by Titanate Nanotubes for Complete Inactivation of Botrytis cinerea Isolated from Tomato Infection

"Antifungal silver nanocomposites inspired by titanate nanotubes (AgTNTs) were successfully evaluated for the effective inactivation of the phytopathogenic fungus Botrytis cinerea within 20 min. One-dimensional H2Ti3O7 nanotubes functionalized with silver nanoparticles (AgNPs) exhibit unique surface and antifungal properties for the photoinactivation of B. cinerea. Nanostructured titanates were synthesized by the eco-friendly, practical, microwave-induced, hydrothermal method followed by a highly monodispersive AgNP UV-photodeposition. Protonated nanotubes of ∼11 nm in diameter and four-layers displayed high surface areas, 300 m2/g, with a size functionalization of 5 nm for the AgNPs. UV–vis DRS and XPS allowed the characterization and/or quantification of surface reactive species and cytotoxic silver species such as Ag°, Ag+. The effective biocidal properties of the nanocomposites were confirmed by using the well-known Gram-negative bacteria Escherichia coli, and then proceeding to the effective inactivation of the phytopathogenic fungus under visible light. The photoassisted inactivation mechanism was examined by HAADF-STEM, HRTEM, and FESEM electronic microscopies. A plasmalemma invagination due to oxidative stress caused by reactive oxygen, silver cytotoxicity species, and AgTNT sharp morphology damage expands the conidia to induce the cell death. The impact of the eco-friendly inactivation is significant because of the ease with which it is carried out and the possibility of being performed in situ with plants like tomato and grapes, which are ranked among the most valuable agricultural products worldwide.

Densely Packed Linear Assembles of Carbon Nanotube Bundles in Polysiloxane-Based Nanocomposite Films

Linear assemblies of carbon nanotubes (LACNTs) were fabricated and controlled in polysiloxane-based nanocomposite films and the effects of the LACNTs on the thermal and electrical properties of the films were investigated. CNTs were dispersed by mechanical stirring and sonication in a prepolymer of polysiloxane. Homogeneous suspensions were cast on polyamide spacers and oriented by linear-assembly by applying DC and switching DC electric fields before the mixture became cross-linked. Densely packed LACNTs that fixed the composite film surfaces were fabricated with various structures and thicknesses that depended on the DC and switching DC conditions. Polymer nanocomposites with different LACNT densities exhibited enhanced thermal and electrical conductivities and high optical transmittances. They are considered promising structural materials for electronic sectors in automotive and aerospace applications

A STUDY OF CRACKS AND DAMAGE IN SINGLE CRYSTAL SILICON AND GALLIUM-ARSENIDE INDENTED IN ELECTROLYTIC SOLUTIONS AND AT HIGH TEMPERATURE (SURFACE DEFORMATION, CHEMOMECHANICAL EFFECT).

A STUDY OF CRACKS AND DAMAGE IN SINGLE CRYSTAL SILICON AND GALLIUM-ARSENIDE INDENTED IN ELECTROLYTIC SOLUTIONS AND AT HIGH TEMPERATURE (SURFACE DEFORMATION, CHEMOMECHANICAL EFFECT)

The role of silver nanoparticles functionalized on TiO2 for photocatalytic disinfection of harmful algae

"Silver loaded TiO2 samples were prepared by photodeposition of different amounts of Ag+ ions over commercial titanium dioxide (Evonik TiO2 P25) in aqueous media without the presence of sacrificial agents. The obtained photocatalysts were characterized by several techniques such as X-ray powder diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) in order to correlate the effect of the silver amount on the photocatalytic properties of the final nanocomposite. The effect of the silver nanoparticles on the photocatalytic behaviour of TiO2 was evaluated by means of the photodegradation of methyl orange dye and the inactivation of noxious algae Tetraselmis suecica and Amphidium carterae under continuous exposure of low power irradiation UV-light. The sample with 1.5% wt of silver nanoparticles showed the highest photocatalytic elimination of the azo dye and both algae types. According to the results, the cells were deformed during the photocatalytic process by the attack of highly reactive species such as hydroxyl radicals, H2O2 and superoxide ions generated on the TiO2 surface. The algae cells were not regenerated by themselves after the photocatalytic process due the high degree of fragmentation that they suffered during the light irradiation.

The effect of laser surface texturing on the tribological performance of different Sialon ceramic phases

A tribological performance was carried out on different types of hot press Sialon ceramics regarding the phases, i.e., the α-Sialon phase, the β-Sialon phase, and the α/β-Sialon composite phase. The different phases of Sialon ceramics were analyzed by XRD patterns. For the tribological performance, the Sialon ceramics were laser textured and the starved lubrication method was applied with different dimple pitches under a load of 10 N at room temperature. The material having a dimple pitch of 200 µm shows the lowest coefficient of friction. The α/β-Sialon composite phase shows the least coefficient of friction i.e. 0.04 and 0.1 for the textured and polished (without being textured) samples, respectively. The Sialon ceramics show mild wear and therefore, the wear rate of the steel ball (mating partner) was taken into account for the wear analysis. The α-Sialon phase having a higher hardness shows the least wear in comparison to the α/β-Sialon composite phase and the β-Sialon phase

Influence of operational parameters on the photocatalytic performance of DE-NOx process Via MIL-101(Fe)

Metal organic framework (MOF) has been paid great attention as a potential candidate for various applications in the field of energy and environment, particularly in air purification. Among various MOFs, MIL-101(Fe) represents an interesting material possessing many advantages, including the ease of fabrication, high porosity, high specific surface area with open metal sites, making it a promising material in the field of harmful gas treatment. Taking these advantages, MIL-101(Fe) was synthesized by facile microwave-solvothermal method and applied as a photocatalyst for the degradation of NOx. The de-NOx efficiency of the synthesized powder was evaluated with respect to various operating parameters including substrates, sample doses, light spectrum and light intensity, initial NO concentration, and relative humidity. The results have shown that the efficiency of NOx photocatalytic degradation reaches to 77% under solar irradiation via 0.1 g of MIL-101(Fe) with optimum condition of reaction, (alumina substrate, 350 ppb of initial NO concentration, 40–50% of relative humidity). Then this work provides the optimum condition for the efficient photocatalytic degradation of NOx. Keywords: Metal-organic framework, MIL-101, Gaseous pollutant, NOx emission, Photocatalys

Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes) junction for dye sensitized solar cells

The dye sensitized solar cell (DSSC), which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film