Functionally graded bioactive glass coating on magnesia partially stabilized zirconia (Mg-PSZ) for enhanced biocompatibility

The coating of magnesia partially stabilized zirconia (Mg-PSZ) with a bioactive glass was investigated for enhancing the bioactivity and bone-bonding ability of Mg-PSZ orthopedic implants. Individual coatings of three different bioactive glasses were prepared by depositing a concentrated suspension of the glass particles on Mg-PSZ substrates, followed by sintering at temperatures between 750 °C and 850 °C. Two silicate-based glass compositions (designated 13–93 and 6P68), and a borosilicate glass composition (H12) were investigated. The microstructure and adhesive strength of the coatings were characterized, and the in vitro bioactivity of the glasses was compared by measuring their conversion kinetics to hydroxyapatite in an aqueous phosphate solution at 37 °C. The 6P68 glass provided the highest adhesive strength (40 ± 2 MPa) but showed very limited bioactivity, whereas the H12 glass had lower adhesive strength (18 ± 2 MPa) but the highest bioactivity. A functionally graded coating, consisting of a 6P68 interfacial layer and an H12 surface layer, was developed to provide a coating with high adhesive strength coupled with rapid in vitro bioactivity.     

NOx removal from the flue gas of oil-fired boiler using a multistage plasma-catalyst hybrid system

The study on removal of NO_x from the flue gas of oil-fired boiler has been carried out using non-thermal plasma cum catalyst hybrid reactor at 150 °C. Propylene (C₃H₆) was used as a reducing agent. A multistage plasma-catalyst hybrid reactor was newly designed and successfully operated to clean up the flue gas stream having a flow rate of 30 Nm³/h. TiO₂ and Pd/ZrO₂ wash-coated on cordierite honeycomb were used as catalysts in the present study. Though the plasma-catalyst hybrid reactor with TiO₂ showed good activity on the removal of NO yet it removed only 50–60% of NO_x because a significant portion of NO oxidized to NO₂. On the contrary, the plasma-catalyst hybrid reactor with Pd/ZrO₂ removed about 50% of inlet NO with a negligible amount of NO oxidation into NO₂. The plasma/dual-catalysts hybrid system (front two units of plasma-Pd/ZrO₂ + rear two units of plasma/TiO₂) proved to be very promising in NO_x removal in the presence of C₃H₆. DeNO_x efficiency of about 74% has been achieved at a space velocity of 3300/h at 150 °C.     

CFD as a tool in risk assessment of inhaled radon progenies

During the last decade, computational fluid dynamics techniques proved to be a powerful tool in the modelling of biological processes and the design of biomedical devices. In this work, a computational fluid dynamics method was applied to model the transport of inhaled air and radioactive particles within the human respiratory tract. A finite volume numerical approach was used to compute the flow field characteristics and particle trajectories in the lumen of the first five airway generations of the human tracheobronchial tree, leading to the right upper lobe. The computations were performed for breathing and exposure conditions characteristic of uranium mines and homes. Primary radon daughter deposition patterns and energy distributions were computed, exhibiting highly inhomogeneous particle and energy deposition patterns. The results of the present modelling effort can serve as input data in lung cancer risk analysis.     

Solar atmospheric magnetic effects on global acoustic and atmospheric gravity eigenoscillations

Solar global observations suggest that the frequency and the line width of helioseismic acoustic eigenmodes vary with the solar cycle. One reason for the measured changes could be the variation of the global atmospheric magnetic fields. We model global solar oscillations in a plane-parallel, three-layer model within the framework of linear dissipative magnetohydrodynamics, and study the effects of a homogenous, horizontal atmospheric magnetic field on global oscillations. We find magnetoacoustic f- and p-modes and also atmospheric gravity modes (g-modes) among the eigenoscillations of the system. We conclude that changes in the atmospheric magnetic field can, significantly, shift the frequencies and vary the line width of global oscillation modes.     

Application of sputtered ceramic TiC/a:C thin films with different structures by changing the deposition parameters

Titanium carbide-based thin films have been produced by DC magnetron sputtering. It was demonstrated that the same technology with changing of the deposition parameters, such as deposition temperature or power of Ti target, resulted in the preparation of TiC/a:C thin films with various structures. The structure of thin films and volume fraction of amorphous and crystal phases were precisely tailored by the control of deposition parameters. These ceramic nanocomposite TiC/a:C thin films according to their various structures, hence, their different mechanical, tribological, or wetting parameters can be used in wide range of applications.     

One Step Further Beyond Trilinear Interpolation and Central Differences: Triquadratic Reconstruction and its Analytic Derivatives at the Cost of One Additional Texture Fetch

Recently, it has been shown that the quality of GPU-based trilinear volume resampling can be significantly improved if the six additional trilinear samples evaluated for the gradient estimation also contribute to the reconstruction of the underlying function [Csé19]. Although this improvement increases the approximation order from two to three without any extra cost, the continuity order remains C⁰. In this paper, we go one step further showing that a C¹ continuous triquadratic B-spline reconstruction and its analytic partial derivatives can be evaluated by taking only one more trilinear sample into account. Thus, our method is the first volume-resampling technique that is nearly as fast as trilinear interpolation combined with on-the-fly central differencing, but provides a higher-quality reconstruction together with a consistent analytic gradient calculation. Furthermore, we show that our fast evaluation scheme can also be adapted to the Mitchell-Netravali [MN88] notch filter, for which a fast GPU implementation has not been known so far.     

Eco-friendly preparation and structural characterization of calcium silicates derived from eggshell and silica gel

In this work, the preparation of calcium–silicate-based composites consisting of natural waste from calcium source as eggshell and silica gel from a desiccator as a silicon source both presenting alternative materials for cheap preparation of eco-friendly calcium–silicate bioceramics has been investigated. The effect of the CaO/SiO₂ ratio on microstructural properties has also been studied. The pseudowollastonite formation has been observed in the case of 40 wt.% CaO and 60 wt.% SiO₂ with lowest porosity and highest density 2.6 g/cm³. In the case of 50 wt.% CaO and 50 wt.% SiO₂, the phase transformation from pseudowollastonite to wollastonite was observed. Increasing the calcium content caused higher apparent porosity with 19%. It was shown that the development of novel ceramics from reused waste, eggshell, or silica can be an optimal solution for the low-cost preparation of calcium silicates with potential applications in medicine or cement, food industry.     

Fabrication of Glass-Ceramic 3D Micro-Optics by Combining Laser Lithography and Calcination

This perspective is an overview of a recent direction in optical 3D printing, where polymerization of crosslinkable materials and nanomaterial fillers can be guided to the final structures and new composites via high temperature annealing (HTA). Defining 3D nano/micro-structures by ultrafast laser direct writing and tailoring their precursor composition with subsequent tunability of the final properties during 750–1500 °C HTA step takes place at the large surface-to-volume ratio conditions favoring efficient pyrolysis and calcination, which are required for exchange of chemical materials/gases between glass/ceramic phase and surrounding. Previously, unexplored inorganic material formation conditions in terms of fast thermal quenching, composition mixing and surface tension guided formation can be harnessed by glass making for creation of new materials endowed with preferable technical properties. An immediate application perspective for a high durability, integrated, and active 3D micro-optics is foreseen.