Class Of Modern Materials Research Articles

A review on UiO-66 applications in membrane-based water treatment processes

Metal-organic frameworks (MOFs) are a modern class of materials that got great academic attention over the last two decades. Recently, serious attempts were conscripted to scale up several types of them and involve industrial applications. UiO-66 is a zirconium-based MOF that was synthesized in 2008 and widely applied in many fields since then. As researchers investigated UiO-66 applications, this material continuously showed high performance and remarkable properties, which increased the interest for further exploitation. In water treatment, where many MOFs are utilized in various processes, UiO-66 is among the intensively applied ones mainly due to its high-water stability. However, the UiO-66's stability is not limited to water; it is stable in organics and acids, in addition to its high thermal stability. Moreover, UiO-66 has the general MOF properties of large surface area, proper pore diameter, large pore volume, functional surface, etc.In this review, we will focus on the use of UiO-66 in membrane-based water treatment processes. These processes include ultrafiltration, nanofiltration, forward osmosis, and reverse osmosis, which are used for dyes, heavy metals, proteins, and antibiotics removal, as well as desalination. Based on database information, UiO-66 use in water treatment is constantly increasing due to the promising opportunities this material raises. Here, it became necessary to explain the up-to-date progress in the membranes field and explore the available future aspects and aspirations of UiO-66.

The shining brightness of daylight fluorescent pigments: Raman and SERS study of a modern class of painting materials

Raman and surface enhanced Raman spectroscopy (SERS) are established techniques allowing for fast and sensitive identification of dyes and pigments. To date, Raman has only limitedly been applied to the identification of daylight fluorescent pigments, despite this modern class of materials has been adopted by several significant artists (e.g. Frank Stella, Peter Halley, Andy Warhol, and Keith Haring).In this study, seven commercial daylight fluorescent pigments from Radiant were investigated by Raman and SERS spectroscopy. A new type of silver colloid, consisting mainly of rod-like silver nanostructures guaranteeing a high SERS enhancement, has been employed here for the first time in cultural heritage studies.As the number of fluorescent dyes suitable for the manufacturing of daylight fluorescent pigments is limited, these materials are often constituted by a mixture of dyes. Since SERS is not able to physically separate multiple dyes in mixtures, to reveal the complex composition of these materials the coupling of SERS with a separation technique proved to be mandatory. Thin-layer chromatography, being a cost-effective and fast procedure, was chosen for this purpose. The identification of each component was made possible by the comparison of SERS spectra from standard fluorescent dyes, thus increasing the available SERS database for modern materials.Lastly, the analytical protocol was applied to a modern artwork called “Rosso verde nero”, made in 1968 by the Italian artist Carla Accardi, who used to paint on plastic surfaces with fluorescent colours.

Experimental Investigation on Energy Absorption of Auxetic Foam-filled Thin-walled Square Tubes under Quasi-static Loading

Auxetic materials are modern class of materials that have recently been gaining popularity within the research community due to their enhanced mechanical properties. Unlike conventional materials, they exhibit a negative Poisson's ratio when subjected to a uniaxial loading. This present research experimentally investigates the crush response and energy absorption performances of auxetic foam-filled square tubes under axial loading. For comparison, the crush response and energy absorption of empty and conventional foam-filled squares tubes have also been examined with respect to deformation modes and force displacement curve. Standard compression tests were conducted on a series number of thin-walled tube samples. An additional compression test on conventional and auxetic foam has also been conducted to observe the behavior of foam itself. It is evident that the auxetic foam-filled square tubes are superior to empty and conventional foam-filled square tubes in terms of energy absorption capacity. It shows that such tube is preferable as an impact energy absorber due to their ability to withstand axial loads effectively. Furthermore, it is found that the load capacity increases as the crush length increases. The primary outcome of this study is design information for the use of auxetic foam-filled square tubes as energy absorbers where impact loading is expected particularly in crashworthiness applications.

Model Based Estimation of Geometric Characteristics of Open Foams

Open cell foams are a class of modern materials which is interesting for a wide variety of applications and which is not accessible to classical materialography based on 2d images. 3d imaging by micro computed tomography is a practicable alternative. Analysis of the resulting volume images is either based on a simple binarisation of the image or on so-called cell reconstruction by image processing. The first approach allows to estimate mean characteristics like the mean cell volume using the typical cell of a random spatial tessellation as model for the cell shape. The cell reconstruction allows estimation of empirical distributions of cell characteristics. This paper summarises the theoretical background for the first method, in particular estimation of the intrinsic volumes and their densities from discretized data and models for random spatial tessellations. The accuracy of the estimation method is assessed using the dilated edge systems of simulated random spatial tessellations.

Structure formation in a chromium carbide alloy of eutectic type during sintering

Alloys of eutectic type constitute a large class of modern materials for a variety of technical applications. Among them, of special interest are the alloys based on refractory compounds, in particular, chromium carbides. It has been reported that chromium carbide alloys with an iron matrix are being used as heatand wear-resisting tool materials [i, 2], but there are no systematic data on structure formation in these materials during sintering.