Biomimetic Method has been widely used to prepare calcium phosphate coatings on Ti and its alloys. This modification is based on a Synthetic/simulated Body Fluid (BSF) which facilitates the mimicking of the biological process in order to provide hard tissue repairs. The formation of HA and other calcium phosphates under biological medium and SBF occurs in the presence of Ca2+ and PO43- ions, as well as essential ions such as: Mg2+, HCO3-, K+ and Na+. Ti-15Mo alloy samples were irradiated by pulsed Yb: YAG pulsed laser beam under air and atmospheric pressure. Sequentially, calcium phosphate coatings were deposited on the irradiated surfaces by the biomimetic method. The biomimetic calcium phosphates-based surfaces were submitted to heat treatment conditions at 350°C and 600°C. The present study correlates two conditions of fluency (1,91 and 5,54 J.cm-2) as established have a sufficient energy to promote ablation on the laser beam irradiated surfaces. Likewise, it has been demonstrated the processes of fusion and fast solidification from the laser beam irradiation, under ambient atmosphere, inducing the formation of stoichiometric TiO2 and non-stoichiometric titanium oxides, including Ti3O5, TiO, Ti3O and Ti6O with different oxide percentages depending on the fluency applied. Besides that, laser modification has allowed a clean and reproducible process, providing no traces of contamination, an important feature for clinical applications. The physico-chemical and morphological analysis indicated the formation of a multiphase coatings depending on the heat treatment temperature performed to 350 °C (ACP1 and 2, HAD, HA phases) and 600 °C (HAD, HA and β-TCP phases). It is worth noting that multiphasic bioceramic systems has been gaining attention for biomedical applications. Thus, the laser beam irradiation associated to bioactive coatings of calcium phosphates of biological interest have shown to be promising and economically feasible for use in dental and orthopedic implants.

Growth of single-walled carbon nanotube (SWCNT) was achieved by an alcohol catalytic chemical vapor deposition (CVD) mechanism that was conducted in a high vacuum using Ru catalysts. By optimizing the ethanol pressure, SWCNTs can grow in a wide range of temperature between 500 °C and 900 °C. Both the yield and crystalline quality of SWCNTs reached their maxima at 700 °C. Significantly, the SWCNT growth was achieved even at 450 °C, which was much lower than the growth temperatures that were required for SWCNT growth using Ru catalysts previously. Raman measurements exhibited that the diameter distribution of the SWCNTs that were grown at 450 °C was quite narrow and (11, 4) nanotubes were dominant. The observations of transmission electron microscope (TEM) suggested that the size of the Ru particles were larger than the diameter of SWCNT. Such a relation was similar to the relation observed in the growth of SWCNTs using Pt catalysts.

With the aim of creating novel ceramics for applications in nuclear materials with high radiation tolerance, multiple samples with A-B-O stoichiometries ranging from 215 to 227 were synthesized and characterized by a combination of SEM, XRD, and TEM methods. Single-phase defect-fluorite-type compounds with A = Sm or Yb and B = Ti, Zr, and/or Sn are reported; whereas, pyrochlore structured compounds and lanthanide sesquioxide phases were found as major phases in numerous samples. A series of Y-b-Sn-O samples was successfully prepared as nearly single phase or single phase materials. These are essentially defect fluorites with extra weak peaks, most likely due to X-ray scattering from oxygen or oxygen and metal cations. We describe some interesting TEM data and describe selected area diffraction patterns with complex modulations.

The use of nanostructured materials for enzyme immobilization is an active field of research due to its large surface area and the new emergent properties derived from its size. The present work is focused on the synthesis of magnetic nanoparticles for the adsorption of cysteine-proteolytic enzymes extracted from Bromelia antiacantha Bertol (Bromeliaceae) fruit. The results show that enzyme adsorption is highly dependent on the temperature and pH. The biocatalyst activity increased up to 40 %, once immobilized onto the magnetic nanoparticles. In addition, they can be recovered using a magnet allowing them to be reused up to 5 cycles with a marginal loss (5 %) of the initial activity.

High-Mn Twinning Induced Plasticity (TWIP) steels are an excellent alternative in the design of structural components for the automotive industry. The TWIP steels application allows weight reduction, maintaining the performance of vehicles. Nowadays the research works focused on TWIP steel weldability are relative scarce. It is well-known that weldability is one of the main limitations for industrial application of TWIP steel. The main goal of this research work was studied the effect of heat input on the microstructural changes generated in a TWIP steel microalloyed with Ti. A pair of welds were performed through Gas Tungsten Arc Welding (GTAW) process. The GTAW process was carried out without filler material, using Direc Current Electrode Negative (DCEN), tungsten electrode EWTh-2 and Ar as shielding gas. The microstructure and average grain size in the fusion (FZ) and heat affected zone (HAZ) were determined by light optical metallography (LOM). Elements segregation in the FZ was evaluated using point and elemental mapping chemical analysis (EPMA) by Scanning Electron Microscopy and Electron Dispersive Spectroscopy (SEM-EDS). Phase transformations were evaluated using X-ray diffraction (XRD). Finally, the hardness were measured by means of Vickers microhardness testing (HV500). The results show that the FZ is characterized by a dendritic solidification pattern. Meanwhile, the HAZ presented equiaxed grains in both weld joints. On the other hand, the TWIP-Ti steel weldments did not present austenite phase transformations. Nevertheless, the FZ exhibited variations in the chemical elements distribution (Mn, Al, Si and C), which were higher as the heat input increases. Finally, the heat input reduced the microhardness of TWIP-Ti steel weld joints. Although post-welding hardness recovery was detected, which is associated with precipitation of Ti second-phase particles.

Due to extremely high conductivity of copper (Cu), copper–based nanocomposites offer remarkable opportunities for use in energy conversion and storage. Their applications demand low-cost syntheses routes relying on using inexpensive equipment with no formation of hazardous wastes. In this work, we report on a novel, cheap and environmentally friendly synthesis and application of nano-porous Cu as a support for lithium titanate. The infiltration of lithium titanate onto the inner surface of NPCu produced high-rate anodes for Li-ion batteries capable of providing nearly 50mAh/g during about 20s charging while retaining about 70% of the initial capacity after 1000 charge-discharge cycles. The demonstrated versatility and simplicity of this fascinating approach show great promises for scalable production and the use of NPCu in various cost-sensitive applications.

In the industry, the titanium nitride (TiN) coating is widely used in cutting tools, decorative and corrosion protection film, but unfortunately, this coating presented a poor performance under some work condition. For that, different studies have been dedicated to improving its properties with the inclusion of a third element that modifies the film structure, chemical and mechanical properties. In this work, TiN layers with/without of Al, B, and Cr inclusion were studied in order to analyze their effect in the film tribological performance. These were deposited using cathodic arc PVD technic on AISI-M2 steel. They were chemical and structural characterized using EDX and XRD, respectively. While the film thickness was determinate using a ball-cratering technique. Their tribological performance was studied using a sliding reciprocating movement in dry conditions, under three loads, at 30 min against Al2O3 ball as counterbody. The resulting wear tracks were studied using optical microscopy in order to study the wear mechanism. Raman spectroscopy was used to determinate the chemical changes produced on wear zones and the lost material was measured with a stylus profilometer. As result, the structure and morphology were modified with the inclusion of the third element. The TiN with the inclusion of Al and B presented a higher friction force and wear rate than TiN films. While the TiN with Cr inclusion film presented the best tribological performance with lower wear rate and friction coefficient. The Raman studies did not showed considerable changes on the damage coted surface areas, except for TiAlN coating that show the M2 tool steel Raman spectra on the areas where the film was removed.

The dynamics of the gas release at thermal oxidation of the two-phase systems of 30% solution of tri-n-butyl phosphate (TBP) in isoparaffinic diluent Isopar M – aqueous solution of 4.3, 8.2 and 12 mol/L of HNO3 has been investigated within the temperature range from 70°C to 110°C. The effect of pre-irradiation of the system TBP–Isopar-M–HNO3 on the kinetics of its thermolysis has been determined. All of the samples were irradiated with an electron accelerator at a dose rate of 10 kGy/h up to integrated doses of 0.5, 1 and 2 MGy. The parameters of heat and gas emission during thermolysis of the tested extraction system in an open apparatus have been determined experimentally. It has been demonstrated, that there are no conditions for extension of autocatalytic oxidation under heat treatment of two-phase extraction systems in open vessels.

Typical electron transport (2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)) and injection (Cs2CO3) materials are successfully replaced by zirconium tetrakis(8-hydroxyquinolinolate) (Zrq4) and lithium 2-((o-tolylimino)methyl)-phenolate (EI-111) in simplified OLED (organic light-emitting diodes) processed by organic vapor phase deposition (OVPD). The performance of combining Zrq4 and EI-111 is analyzed in unipolar devices and compared to devices with configurations of Zrq4/Cs2CO3, TPBi/EI-111 and TPBi/Cs2CO3. Current density-voltage (J-V) measurements are performed and correlated to different carrier injection and transport properties. The investigated material combinations are implemented in the simplified OLED structures and compared to each other. To account for the high HOMO level of Zrq4, 5 nm of TPBi are added to confine holes and excitons in the emissive layer (EML) and to improve device performance. After tailoring the organic stack for OLED with Zrq4, a remarkable boost in device efficiency is observed. The luminous efficacy increased from 3.0 to 21.9 lm/W and the EQE from 2.1 to 11.0 % for a device with Zrq4/EI-111. Furthermore, OLED having Zrq4/Cs2CO3 show an even greater enhancement to 26.3 lm/W and 11.7 %.

Computational electrodynamics simulations provide a critical complement to experimental investigations for the understanding of light-matter interaction in complex systems. Its success is due in part to its relative simplicity and ease of use, coupled with its broad applicability to many material systems and optical processes. First, we will review our recent work in nanophotonics. While computational electrodynamics has been, and continues to be, very widely used in plasmonics, there are significant issues in convergence and accuracy, which we have studied in detail, and which sometimes point to the need for parallel computing. With access to large computational resources, we are able to study complex arrangements of dielectric and plasmonic objects, including metallic nanoparticle distributions for color production, hybrid dielectric/plasmonic nanoantennas for enhancement of third harmonic generation, and metasurfaces for nonlinear light control and structuring. Second, we will discuss our computational electrodynamics simulations of nonlinear optical microscopy experiments. Our tool includes high numerical aperture light sources, propagation through heterogeneous media, nonlinear near-field interaction, subsequent propagation to the far field, and integration over a collecting lens. We have used this to unravel the image formation mechanisms in nonlinear optical microscopy, such as CARS and SHG microscopy. We find that the images are not a one-to-one density map of the object, but rather that the sub-micrometer to nanometer structure of the object, along with the coherence of parametric nonlinear optical processes, can be imprinted in the image in surprising ways.

Tunable plasmonic resonances across the visible and near infrared spectra have provided novel ways to develop next-generation nanophotonic devices. Here, by utilizing optothermally controllable phase-changing material (PCM), we studied highly tunable charge transfer plasmon (CTP) resonance modes. To this end, we have designed a two-member dimer assembly including gold cores and Ge2Sb2Te5 (GST) shells in distant, touching, and overlapping conditions. We successfully demonstrated that toggling between amorphous (dielectric) and crystalline (conductive) phases of GST allows for achieving tunable dipolar and CTP resonances along the near-infrared spectrum. The proposed dimer structures can help forming optothermally controlled devices without further morphological variations in the geometry of the design, and having strong potential for advanced plasmon modulation and fast data routing.

Second-order diffraction (SOD) of x-rays refers to all diffraction processes where the photons reaching the detector have been diffracted twice within a crystal lattice. By measuring the two dimensional intensity profile of SOD, it is possible to distinguishing rescattering processes taking place inside each grain (perfect crystal domain) or in between grains. These two SOD regimes, usually called dynamical and kinematical, respectively, are ruled by size and relative orientation of the grains. In this work, we demonstrate how to explore SOD phenomena to understand the micro scale grain structure in plastically deformed silicon single crystal.