Structuring and functionalization of non-metallic materials using direct laser interference patterning: a review

Direct laser interference patterning (DLIP) is a laser-based surface structuring method that stands out for its high throughput, flexibility and resolution for laboratory and industrial manufacturing. This top–down technique relies on the formation of an interference pattern by overlapping multiple laser beams onto the sample surface and thus producing a periodic texture by melting and/or ablating the material. Driven by the large industrial sectors, DLIP has been extensively used in the last decades to functionalize metallic surfaces, such as steel, aluminium, copper or nickel. Even so, DLIP processing of non-metallic materials has been gaining popularity in promising fields such as photonics, optoelectronics, nanotechnology and biomedicine. This review aims to comprehensively collect the main findings of DLIP structuring of polymers, ceramics, composites, semiconductors and other non-metals and outline their most relevant results. This contribution also presents the mechanisms by which laser radiation interacts with non-metallic materials in the DLIP process and summarizes the developed surface functions and their applications in different fields.

The Effect of Dissolved Elements and Inclusions on the Properties of Metal Products

The chapter deals mainly with the effect of impurities on the macro properties of metals made from steel, aluminium, copper, and zinc. It is about porosity, mechanical properties, strength, fatigue, and corrosion. It shows the effect of small amounts of inclusions and liquid impurities in bulk, on grain boundaries, and on the surface of the metals. The investigations have been carried out using mechanical tests, and advanced microscopic instruments like electron microscopes, X-ray diffraction, and different SIMS instruments (secondary ion mass spectrometry). The chapter lays the foundation for the need for refining of primary and secondary metals, i.e. recycling.

Trace Scandium addition on the strength and thermal stability of TiB2 particles reinforced Al-4.5 Cu composites

Strategies employed for developing ultrahigh strength and scalable ductile particles reinforced aluminium-copper matrix composites (AMCs) are highly desirable and grandly challenging. In the present paper, the Scandium (Sc) micro-alloying TiB2 particles reinforced Al-4.5 Cu composites were successfully fabricated by the optimized salt-metal reaction method. The observed microstructures displayed that Sc addition could remarkably ameliorate the dispersion of TiB2 particles, enlarge equiaxed α-Al grain zone and refine the grains on the basis of TiB2 heterogeneous nucleation. In particular, for the 0.4 wt.% Sc microalloyed 5%TiB2/Al-4.5Cu composites, more than a 20 %, 87 %, and 118 % increase in the ultimate tensile strength (UTS), fracture strain elongation (%) and microhardness (HV), respectively were found with respect to the 3 %TiB2/Al-4.5Cu composites at room temperature (298K). The improved mechanical properties of strength-ductility synergy were mainly thanks to the homogeneous distribution of TiB2 particles and modification of Al2Cu phase. Moreover, proper Sc also enhanced the elevated-temperature mechanical properties of the composites with the aid of the accelerated precipitation of θ′ phase and much lower coarsens rate.

Aqueous aluminium–copper hybrid nanofluid flow past a sinusoidal cylinder considering three-dimensional magnetic field and slip boundary condition

We analyzed the problem of the steady general three-dimensional magnetohydrodynamics stagnation-point boundary layer flow past an impermeable wavy circular cylinder considering aluminium–copper/water hybrid nanofluid as the working fluid and velocity slip as well as temperature jump boundary conditions. The induced magnetic field effect was also taken into account. The analytical procedure is based on the model that implements the nanoparticles and base fluid masses to formulate the equivalent volume fraction, equivalent density, and equivalent specific heat at constant pressure which is then substituted in the chosen single-phase thermophysical properties. Then, the foregoing relations were used in basic governing PDEs (partial differential equations), according to Tiwari–Das nanofluid scheme. It is worth mentioning that the bvp4c code from MATLAB software that is a famous finite-difference method has been exploited for solving the final similarity ODEs (ordinary differential equations). Results demonstrate that the developed mass-based model can be successfully employed with great confidence to study the flow and heat transfer of hybrid nanofluid in other similar problems. Moreover, it is proved that the nodal stagnation points possess higher values of skin friction coefficients and local Nusselt numbers relative to those for the saddle stagnation points. Besides, enhancing the second nanoparticle's mass leads to increase in all parameters of engineering interest including skin friction coefficients along x and y directions as well as local Nusselt number.

CT image quality influence on different material Edge Response Functions for accurate metrological applications

The main objective of the proposed work was to analyse the influence of magnification and focal spot size scan settings on X-ray computed tomography (CT) measurements results under commercial threshold-based algorithms. The relationship between spatial resolution and contrast sensitivity in CT scans of different materials and the accuracy of the resulting CT measurement results is discussed. For that purpose, Aluminium, Copper, Inconel 718 and Titanium disk phantoms were scanned. Preliminary measurements showed that deviations can increase up to 0.48% when the scanning magnification was increased while, for a given magnification, the decrease of a focus size from 1mm to 0.4mm slightly improves the differences up to 0.15%, being negligible at low magnifications. Unsharpness (U T ) and contrast-to-noise ratio (CNR) were calculated for each scanning conditions according to standard ASTM E1695 – 20. A new image quality indicator that includes the combined effect of the U T and CNR was proposed in order to relate measurement error with the image quality. The indicator proves that the influence of CNR is much higher than influence of U T on the CT measurements.

Coronavirus survival time on inanimate surfaces: a systematic review

This systematic review aimed to study the survival time of the virus from the coronavidae family on various materials and surfaces, thus enabling the adoption of preventive measures mainly in public environments. The electronic databases selected as a source of information were PubMed/Medline, Excerpta Medica database (EMBASE), Latin American and Caribbean Literature in Health Sciences (LILACS), Web of Science, Scopus, and LIVIVO; grey literature (Google Scholar, ProQuest, and OpenGrey) was also examined. The last electronic search of the six databases retrieved 4287 references. After removing the duplicate references, the titles and abstracts (phase 1) were read, and 37 articles were selected for complete reading (phase 2), which resulted in 13 included studies. All the studies evaluated coronavirus survival on the following surfaces and objects: stainless steel, glass, plastic, wood, metal, cloth, paper, cotton, latex, polystyrene petri dish, aluminium, copper, cardboard, Teflon, polyvinyl chloride (PVC), silicone rubber and disposable fabric. On surfaces such as glass, plastic, and steel, the virus has greater stability than it does on copper, fabric, paper, and cardboard. The conditions of temperature, relative humidity, absorption power, and texture were also considered important factors in the survival of the virus.

Influence of temperature dependent physical properties on liquid metal droplet impact dynamics

The dynamics of a metal droplet impacting on a substrate surface has been studied in the paper numerically. Numerical solutions of the Navier-Stokes and Energy equations show the evolution of the droplet as it spreads upon impact with the substrate while simultaneously undergoing solidification. The interplay of the different forces including inertia, viscous and surface tension, coupled with solidification of the molten material in layers lead to complex flow dynamics. The change in density and viscosity owing to change in temperature resulting from the cooling process, is found to influence the spreading of the droplet significantly. The model was exercised for three different materials viz. aluminium, copper and nickel to determine the final splat radius as well as spreading time. The surface tension forces as well as solidification rates were found to be the dominant factors in determining the above parameters as well as the shape of the splat during spreading. The results were found to be in good agreement with existing analytical model.

Determination of Aluminium Concentrations in White Tea Samples

Objectives Tea is a popular drink around the world. To date several studies showed that tea might be exposed to toxic chemical contaminants. Aluminium (Al) is one of the metals contaminating tea. This study aimed to evaluate the Al concentrations in white tea. Methods Commercially available tea samples were brewed in 5 different teapots, consisting of aluminium, copper, glass, steel and porcelain materials for 5, 10, and 15 minutes. Al concentrations in tea samples were determined by high-performance liquid chromatography with fluorescence detector. The hazard quotient (HQ) was calculated according to 70 kg body weight and 10 g/day tea consumption. HQ value less than 1 (HQ ˂ 1) is considered safe. The relationship between tea types, teapot type and brewing time factors were determined using 3-way ANOVA test. Bonferroni correction was applied for multiple comparisons. Results Al concentrations in white tea samples were in the range of 181.97 ± 11.88 – 352.45 ± 5.86 µg/L. Both teapot type (p < 0.001) and brewing time (p < 0.001) significantly influenced Al concentrations in tea samples. The interaction between teapot material and brewing time was statistically significant (p < 0.001). The hazard ratio was less than 1 for white tea infusions except for one sample, which was brewed in glass teapot for 15 min. Conclusions It was found that white tea consumption might be a potential risk factor for Al exposure. Funding Sources None declared.