Influence investigation of technological conditions of 3D-printing on antiadhesion properties of master-model surfaces

It is shown that one of the promising methods to prepare a master-model for the casting production of engineering industry products is FDM 3D-printing. The influence of technological conditions of 3D-printing on antiadhesion properties of surfaces has been studied. By experiments it was found out that for 3D-printing of master-models it was necessary to have conditions in which the parameter of filling percent was more than 60%. Recommendations for the use of 3D-printing methods for production of casting molds are given.

Estimation SARS-CoV-2 viability in time on experimental surfaces over

Infected SARS-CoV-2 virus occurs not only through contact with an infected person, but also through surfaces with wich the illnes has contacted. The problem of preserving an infectious virus over time capable of infecting remains actual. We evaluated the SARS-CoV-2 viability preservation on different model surfaces over time. Ceramic tiles, metal (aluminum foil), wood (chipboard), plastic and cloth (towel) were used as model materials. Assessment of the presence of SARS-CoV-2 RNA was carried out by quantitative RT-PCR. Viable virus was determined by tissue culture assay on 293T/ACE2 cells. It was found that the SARS-CoV-2 RNA was detected on all studied surfaces for 360 minutes, but a significant decrease RNA by 1 log10 copies/ml was detected after contact of the virus with cloth (towel). While the viability of the virus was completely lost after 120 minutes. Type of experimental surface significantly affects viability preservation.

ALGORITHM FOR THE COUNTERCLOCKWISE ORDERING OF VERTEXES OF SLANTED SURFACES TOWARDS THE GENERATION OF SEMANTIC GBXML MODELS

This paper presents an algorithm developed to solve a problem during the development of a system to estimate de 3D model of buildings roofs and its incorporation into a BIM. The chosen schema for the BIM is gbXML and one of its condition is that the vertexes that describe the model surfaces must be counterclockwise ordered. Due to the variability in the orientation of the analysed surfaces, the algorithm must be able to work with any surface regardless its orientation. Also, this paper includes the testing of the algorithm. This test is based on the application of the developed algorithm among three different real-world scenarios.

SARS-CoV-2 viability in time on experimental surfaces

We evaluated the SARS-CoV-2 viability preservation on different model surfaces over time. It was found that the SARS-CoV-2 RNA was detected on all studied surfaces for 360 minutes, while the viability of the virus was completely lost after 120 minutes. Type of experimental surface significantly affects viability preservation.

Model Surfaces for Paper Fibers Prepared from Carboxymethyl Cellulose and Polycations

For tailored functionalization of cellulose based papers, the interaction between paper fibers and functional additives must be understood. Planar cellulose surfaces represent a suitable model system for studying the binding of additives. In this work, polyelectrolyte multilayers (PEMs) are prepared by alternating dip-coating of the negatively charged cellulose derivate carboxymethyl cellulose and a polycation, either polydiallyldimethylammonium chloride (PDADMAC) or chitosan (CHI). The parameters varied during PEM formation are the concentrations (0.1–5 g/L) and pH (pH = 2–6) of the dipping solutions. Both PEM systems grow exponentially, revealing a high mobility of the polyelectrolytes (PEs). The pH-tunable charge density leads to PEMs with different surface topographies. Quartz crystal microbalance experiments with dissipation monitoring (QCM-D) reveal the pronounced viscoelastic properties of the PEMs. Ellipsometry and atomic force microscopy (AFM) measurements show that the strong and highly charged polycation PDADMAC leads to the formation of smooth PEMs. The weak polycation CHI forms cellulose model surfaces with higher film thicknesses and a tunable roughness. Both PEM systems exhibit a high water uptake when exposed to a humid environment, with the PDADMAC/carboxymethyl cellulose (CMC) PEMs resulting in a water uptake up to 60% and CHI/CMC up to 20%. The resulting PEMs are water-stable, but water swellable model surfaces with a controllable roughness and topography.

Silver oxide model surface improves computational simulation of surface-enhanced Raman spectroscopy on silver nanoparticles

For simulation of SERS on silver nanoparticles, Ag2O can provide a more accurate result than standard model surfaces such as Ag+, Ag, Ag4+ and Ag4.