Comparative study between UVB 313 nm, UVC 254 nm, and far UVC 222 nm light on the aging of polyamide 66.

Polyamide-66 underwent substantial growth worldwide in the late 1930's. It can be found in several public spaces. After 2019, due to the coronavirus disease (COVID-19), the sanitization of the interior of aircraft and public spaces by using UV light became important.

Nanomechanical and bending properties of nickel-titanium orthodontics archwires by depth-sensing indentation.

Introduction: This study aimed to identify the link between alloy microstructures and the nanomechanical properties of different orthodontic archwires containing nickel-titanium (NiTi) by sensing sliced areas. Previous studies have focused on analyzing and contrasting physical properties such as microhardness, elasticity modulus, and resistance; therefore, the trend is to consider microstructural characteristics in detail.

Methods: Thirty archwire samples from 3 different commercial brands, American Orthodontics (AO), 3M Unitek (3M), and Borgatta, were analyzed through scanning electron microscopy and energy-dispersive x-ray spectroscopy, transmission electron microscopy, atomic force microscopy, Berkovich nanoindentation, and microtensile microscopy to determine their chemical-crystallographic characteristics and nanomechanical and bending characteristics.

A New Sustainable PPT Coating Based on Recycled PET to Improve the Durability of Hydraulic Concrete.

A new, sustainable polypropylene terephthalate (PPT) coating was synthesized from recycled polyethylene terephthalate (PET) and applied onto a hydraulic concrete substrate to improve its durability. For the first step, PET bottle wastes were ground and depolymerized by glycolysis using propylene glycol (PG) in a vessel-type reactor (20-180 °C) to synthesize bis(2-hydroxypropyl)-terephthalate (BHPT), which was applied as a coating to one to three layers of hydraulic concrete substrate using the brushing technique and polymerized (150 °C for 15 h) to obtain PPT. PET, BHPT, and PPT were characterized by FT-IR, PET, and PPT using TGA, and the PPT coatings by SEM (thickness), ASTM-D3359-17 (adhesion), and water contact angle (wettability).

Nanomechanical properties of kidney stones, gallstones and oral stones compared with tap water scale by depth sensing indentation.

This article focuses on a description of research performed to identify structural and mechanical properties differences between calculi in stones, such as gallstones, kidney stones, dental tartar, and saliva gland sialolite, were analyzed and compared with tap water stone, in order to set interrelations. In this study, biological hard pebble-like structures were analyzed and compared among them using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), and Atomic Force Microscopy (AFM). In addition, Nanoindentation was used to obtain values as example in kidney stones the in; stiffness S = 27,827 ± 620 N/nm elastic modulus E = 27.

Green Synthesis for Carbon Quantum Dots via and : Surface-Enhanced Raman Scattering Sensing Applications.

In this study, we present an alternative method for synthesizing carbon quantum dots (CQDs) using a green synthesis approach via extracts from and . The extracts from both plants were used as the carbon source for the CQDs. The synthesis method employs mesoporous zeolite 4A as a refractory for the thermal treatment of the samples.

Structural Analysis of Cu and Cu Ions in Zeolite as a Nanoreactor with Antibacterial Applications.

In this work, we report the structural analysis of Cu and Cu ions in zeolite as a nanoreactor with antibacterial applications. A simple one-step process was implemented to obtain Cu ions in zeolite A (ZA4) by controlling the temperature in the solutions to guarantee the ions' stability. Samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy, showing the characteristic zeolite elements as well as the characteristic bands with slight modifications in the chemical environment of the zeolite nanoreactor attributed to Cu ions by FT-IR spectroscopy.

TiNbN Hard Coating Deposited at Varied Substrate Temperature by Cathodic Arc: Tribological Performance under Simulated Cutting Conditions.

This study focused on investigating the adhesion and tribological properties of niobium-doped titanium nitride (TiNbN) coatings deposited on D2 steel substrates at various substrate temperatures (Ts) under simulated cutting conditions. X-ray diffraction confirmed the presence of coatings with an FCC crystalline structure, where Nb substitutes Ti atoms in the TiN lattice. With increasing Ts, the lattice parameter decreased, and the crystallite material transitioned from flat-like to spherical shapes.

Anisotropic behavior of mechanical properties for the- and-domains in a (001) BaTiOsingle crystal.

Barium titanate (BaTiO) single crystal with a tetragonal phase was characterized by nanoindentation. Elastic and elastic-plastic deformation regimes were obtained. The main objective was the evaluation of the anisotropic behavior related to mechanical properties associated with the cross-section of the ferroelectric- and-domains (In-plane and out-of-plane) in (001) configuration domains.

The Piezoresponse in WO Thin Films Due to N-Filled Nanovoids Enrichment by Atom Probe Tomography.

Tungsten trioxide (WO) is a versatile -type semiconductor with outstanding chromogenic properties highly used to fabricate sensors and electrochromic devices. We present a comprehensive experimental study related to piezoresponse with piezoelectric coefficient = 35 pmV on WO thin films ~200 nm deposited using RF-sputtering onto alumina (AlO) substrate with post-deposit annealing treatment of 400 °C in a 3% H/N-forming gas environment. X-ray diffraction (XRD) confirms a mixture of orthorhombic and tetragonal phases of WO with domains with different polarization orientations and hysteresis behavior as observed by piezoresponse force microscopy (PFM).

Hybrid Coatings of SiO-Recycled PET Unsaturated Polyester Resin by Sol-Gel Process.

Hybrid coatings of SiO and recycled unsaturated polyester resin (R-UPR) from recycled polyethylene-terephthalate (PET) were prepared by the sol-gel process on glass substrates. First, SiO was synthesized by the sol-gel process using a tetraethyl orthosilicate (TEOS) solution. Next, bis(2-hydroxypropyl-terephthalate) (BHPT) was synthesized from mechanical and chemical recycling (glycolysis) of post-consumer PET bottles in propylene glycol (PG) using ZnA as catalyst, in a Vessel-type reactor (20-200 °C); maleic anhydride (MA) was added and, following the same procedure, the unsaturated polyester (UP) was synthetized, which was cooled to room temperature.

The Use of Recycled PET for the Synthesis of New Mechanically Improved PVP Composite Nanofibers.

Polyethylene terephthalate (PET) waste has become a major challenge for the conservation of the environment due to difficult degradation. For this reason, it is important to develop new recycling strategies for reusing this waste. In this work, the electrospinning technique was used to synthesize composite nanofibers of polyvinylpyrrolidone (PVP), recycling PET (RPET) that was obtained from the chemical recycling of postconsumer PET with glycolysis and styrene (ST) as a crosslinking agent.

Assessing mechanical behavior of ostrich and equine trabecular and cortical bone based on depth sensing indentation measurements.

Guided bone regeneration surgeries are based on grafting a scaffold in the site to be repaired. The main focus of the scaffold is to provide mechanical support to newly formed blood vessels and cells that will colonize the grafted site, achiving bone regenertation. In this regards, the aim of this study was to characterize the anatomy, structular, surface morphologycal, chemical composition, and nanomechanical properties of ostrich and equine trabecular bone.

Nano-structured hydroxyapatite and titanium dioxide enriching PENTA /UDMA adhesive as aesthetic coating for tooth enamel.

Objectives: The aim of this study was to investigate the effect of the nanostructured hydroxyapatite (NHAp) and titanium dioxide nanoparticles (NTiO) on dispersion in an adhesive containing monomers of Dipenta erythritol penta-acrylate monophosphate (PENTA) and Urethane dimethacrylate (UDMA), as well as evaluating the structural, optical and mechanical behavior of the composite material for dental aesthetic application.

Methods: The NHAp powders were synthesized through the wet chemical methods of hydrothermal and ultrasound-assisted precipitation. The microstructure, morphology and composition analysis of the powder of NHAp and NTiO were performed by scanning and transmission electron microscopy.

Structural Aspects LiNbO₃ Nanoparticles and Their Ferromagnetic Properties.

We present a solid-state synthesis of ferromagnetic lithium niobate nanoparticles (LiNbO₃) and their corresponding structural aspects. In order to investigate the effect of heat treatments, two batches of samples with a heat-treated (HT) and non-heat-treated (nHT) reduction at 650 °C in 5% of hydrogen/argon were considered to investigate the multiferroic properties and their corresponding structural aspects; using magnetometry and scanning transmission electron microscopy (STEM). Results indicate the existence of ferromagnetic domains with a magnetic moment per unit cell of 5.

Hardness and Elastic Modulus on Six-Fold Symmetry Gold Nanoparticles.

The chemical synthesis of gold nanoparticles (NP) by using gold (III) chloride trihydrate (HAuCl∙3H₂O) and sodium citrate as a reducing agent in aqueous conditions at 100 °C is presented here. Gold nanoparticles areformed by a galvanic replacement mechanism as described by Lee and Messiel. Morphology of gold-NP was analyzed by way of high-resolution transmission electron microscopy; results indicate a six-fold icosahedral symmetry with an average size distribution of 22 nm.