Controlling of Lattice Strains for Crack-Free and Strong Ferroelectric Barium Titanate Films by Post-Thermal Treatment

In this study, we experimentally demonstrate the fabrication of ultra-smooth and crystalline barium titanate (BTO) films on magnesium oxide (MgO) substrates by engineering the lattice strain and the crystal structure via thermal treatment. We first grow crack-free BTO thin films at oxygen-depleted condition, and enhance the ferroelectric characteristics by post-annealing at high temperature. The roughened surface due to recrystallization during post-annealing is controlled by chemical-mechanical polishing (CMP) to retain the ultra-smooth surface morphology. Oxygen-depleted deposition allows a highly strained BTO film to grow on a MgO substrate with an ultra-smooth surface, and post-annealing relaxes the strain, resulting in the enhancement of the ferroelectricity. From Raman spectroscopy, reciprocal space map (RSM), and capacitance–voltage (C–V) curve measurements, we observe that the ferroelectricity of the BTO film strongly depends on the lattice strain relaxation and the phase transition from a-axis to c-axis oriented crystal structure.

Clinical and radiological of the effects of two different implant surfaces on marginal tissues

Aim: In this study, our aim is to compare the effects of dental implants with nano laser excimer technology surface (NLE) and dental implant surfaces (MTX) with micro-roughened surface on marginal tissues with clinical and radiological data. Methodology: A total of 117 dental implants were followed clinically and radiologically. Clinically; Plaque index (silness-leöe), bleeding index in boring, pocket depth were evaluated and recorded 1 week after the insertion of the healing cap, 3 months, 6 months and 12 months after the end of the prosthesis. In the same periods, periapical x-rays were taken with the Rinn Holder method and the amount of marginal bone loss was measured. The data were analyzed with IBM SPSS Statistics Version 22 package program. Results: There was no loss in the implants included in the study. There was no statistically significant difference between the groups in terms of plaque index, bleeding index values (p>0,05). However, the pocket depth of the dental implant group with nano laser excimer technology surface is significantly lower than the micro-roughened surface group. There are statistically significant differences between the groups in terms of radiological marginal bone loss at 0, 3, 6, and 12 months (p<0,05). Radiological marginal bone loss values ​​of the micro-roughened surface group at 0, 3, 6, and 12 months were significantly lower compared to the same periods of the nano laser excimer technology group. Conclusion: It has been determined that the surface properties of dental implants can be effective on marginal tissues. In addition, we believe that routine checks by dentists who perform dental implant applications will increase the success of dental implants. How to cite this article: Bingül MB, Gülsün B. Clinical and radiological of the effects of two different implant surfaces on marginal tissues. Int Dent Res 2021;11(Suppl.1):152-9. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.23 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Extraction of Cellulose Polymeric Material from Populus tremula Fibers: Characterization and Application to the Adsorption of Methylene Blue and Crystal Violet

Cellulose is the most widely available biopolymer which is extensively used for several applications including textiles, composites, pharmaceutical, water treatment, etc. In this investigation, cellulose was chemically extracted from Populus tremula seed fibers. Samples were characterized using FT-IR, SEM, XRD, and TGA-DTA analyses. FT-IR spectrum of the extracted cellulose confirmed that hemicellulose and lignin were removed during alkali and bleaching treatments. SEM images showed the partially roughened surface of the fiber due to the removal of non-cellulosic elements and surface impurities during chemical modification. The crystallinity index values for untreated Populus tremula fibers and extracted cellulose were calculated to be 32.8% and 58.9%, respectively. The obvious increase in the crystallinity index for the extracted cellulose confirmed the removal of amorphous compounds present in raw populus. Alkali-treated populus fibers were more thermally stable than raw fibers. All changes observed after alkali and bleaching treatments evidenced the removal of amorphous contents and non-cellulosic components in raw populus fibers. Extracted cellulose exhibited excellent adsorption capacities of methylene blue (140.4 mg g−1) and crystal violet (154 mg g−1). The pseudo second order equation fitted well the kinetic data indicating a chemi-sorption process. The Freundlich model complied well with the experimental data suggesting that the adsorption of the studied dyes was multilayer.

Experimental and numerical evaluations of composite concrete-to-concrete interfacial shear strength under horizontal and normal stresses

Effects of different surface textures on the interface shear strength, interface slip, and failure modes of the concrete-to-concrete bond are examined through finite element numerical model and experimental methods in the presence of the horizontal load with ‘push-off’ technique under different normal stresses. Three different surface textures are considered; smooth, indented, and transversely roughened to finish the top surfaces of the concrete bases. In the three-dimensional modeling via the ABAQUS solver, the Cohesive Zone Model (CZM) is used to simulate the interface shear failure. It is observed that the interface shear strength increases with the applied normal stress. The transversely roughened surface achieves the highest interface shear strength compared with those finished with the indented and smooth approaches. The smooth and indented surfaces are controlled by the adhesive failure mode while the transversely roughened surface is dominated by the cohesive failure mode. Also, it is observed that the CZM approach can accurately model the interface shear failure with 3–29% differences between the modeled and the experimental test findings.

Influence of Roughness and Curing Temperature on the Strength of Aluminum Adhesively Bonded Joints

This work presents a comprehensive experimental study on the effect of surface roughness and adhesive curing temperature on adhesively bonded joints of AA6082. The modification of surface morphology has been assessed by roughness measurements (contact and non-contact profilometry). In addition, mechanical changes in the resin properties due to different curing time have been probed through a series of instrumented indentation tests. Thus, adhesive bonded single lap joints were fabricated and tested to assess the changes in shear strength at varying surface roughness and curing conditions. The obtained results indicate the ability of the roughened surface to improve the joint strength together with the adequate combination of curing temperature and time among those suggested by the manufacturer.

The Imaginary of an Invisible Enemy: The SARS-CoV-2 Virion on the Spanish TV News

During epidemiological crises, tradi­tional media have played an essential informational role. In this paper we analyze the imaginary of COVID-19 and, specifically, of the representa­tion of the virion of the SARS-CoV-2 virus through news reports from the main Spanish TV channels. This virion, represented as an “invisible enemy” that has confined half of the world population, is presented in the news using 3D illustrations that highlight its roughened surface and elongated spikes ending in tentacles, an image that does not cor-respond to scientific illustrations. These and other attributes suggest that the imaginary of COV­ID-19 has inherited the imaginary of other previous episodes of coronavirus­es being not scientifically accurate but motivated by the journalistic objective of representing the main characteris­tics of the virus and the severity of the danger. Keywords: visual communication, health risk communication, television news, COVID-19, pandemic.

Description of Thermochromic Offset Prints Morphologies Depending on Printing Substrate

In this study, the influence of physio-chemical properties of four printing substrates, fibrous papers (filter, bulky, recycled), and polymer film (synthetic paper) on the size of the thermochromic (TC) prints microcapsules was investigated. Results indicate that interaction between thermochromic ink and printing substrate determine the print morphology, i.e., porosity and roughness of printing substrate affect dimensions of TC microcapsules of resulting prints, while ink adhesion affects dimensional changes during heating–cooling cycle. Atomic force microscopy (AFM) analysis showed that microcapsules of the prints, on the surface of the smoothest synthetic paper, possess the smallest diameter and height, while, on the most porous and the most roughened surface of F paper, the microcapsules of the prints possess the highest diameter and height. By increasing the temperature to 40 °C, the biggest changes in the shape of the microcapsules (increase in height and decrease in diameter) were obtained using the surface of the hydrophilic filter paper. While using the recycled paper surface, the situation is opposite; the height and diameter of the microcapsules are reduced, and the microcapsules penetrate deeper into the paper structure (due to optimum adhesion). On the bulky paper surfaces, which are more hydrophobic than recycled paper (higher interfacial tension), the increase of temperature does not cause any significant changes in the shape and position of the microcapsules. The same behavior is observed using hydrophobic non-porous synthetic paper.

Pulsed Waterjet Roughening of Cast Iron and Aluminum Alloy for Automotive Engine Remanufacturing with Plasma Transferred Wire Arc Coating

This study utilized the high-pressure pulsed waterjet process and paired it with the plasma transferred wire arc technology to develop a novel technique to remanufacture damaged engine cylinder bores. The objective of this research was to eliminate the need for expensive bond-coats such as Ni-Al by optimizing the surface roughness profile of the substrate to provide acceptable mechanical bonding between the coating and the substrate. In this study, a high chrome stainless steel wire (Metcoloy #2) was plasma spray coated on a wide range of pulsed waterjet roughened surface profiles generated on grey cast iron and cast aluminum A380 alloy, the two most common engine materials. The pulsed waterjet greatly increased the adhesion strength between the substrates and the Metcoloy #2 coating. The increase in adhesion strength is a result of the formation of favorable mechanical anchoring points. Optimal pulsed waterjet parameters were determined to avoid the production of a copious roughness profile which resulted in a coating that mirrored the roughened surface profile. Additionally, if the roughness profile produced by the pulsed waterjet was insignificant the coating was removed in its entirety during detachment-based failure.