Search results for "Titan"
showing 10 items of 1109 documents
Cell and tissue response to nanotextured Ti6Al4V and Zr implants using high-speed femtosecond laser-induced periodic surface structures
2019
In this paper, the effect of femtosecond laser nanotexturing of surfaces of Ti6Al4V and Zr implants on their biological compatibility is presented and discussed. Highly regular and homogeneous nanostructures with sub-micrometer period were imprinted on implant surfaces. Surfaces were morphologically and chemically investigated by SEM and XPS. HDFa cell lines were used for toxicity and cell viability tests, and subcutaneous implantation was applied to characterize tissue response. HDFa proliferation and in vivo experiments evidenced the strong influence of the surface topography compared to the effect of the surface elemental composition (metal or alloy). The effect of protein adsorption fro…
Electrochemical formation of novel TiO2-ZnO hybrid nanostructures for photoelectrochemical water splitting applications
2020
[EN] In this study, hybrid ZnO-TiO2 nanostructures have been synthesised by means of a simple electrochemical anodisation of titanium and subsequently ZnO electrodeposition. The influence of Zn(NO3)(2) concentration and temperature during the electrodeposition process was evaluated. Different techniques were used to analyse the synthesised nanostructures, notably Field Emission Scanning Electron Microscopy (FE-SEM) with Energy-dispersive X-ray spectroscopy (EDX) and Confocal Microscopy with Raman spectroscopy coupled with an Atomic Force Microscope. Photoelectrochemical water splitting tests were also performed at the hybrid nanostructures. According to the results, the photoelectrochemical…
Synthesis of Titanate Nanotubes Directly Coated with USPIO in Hydrothermal Conditions: A New Detectable Nanocarrier
2011
International audience; Abstract: For the first time, titanate nanotubes (TiONts) coated with USPIO (ultrasmall superparamagnetic iron oxide) without polymer functionalization and directly obtained during TiONts formation is reported. The coating of these tubes was performed directly during the TiONts hydrothermal synthesis. After this treatment, in strongly basic conditions, USPIO particles kept their structure and magnetic properties while their size distribution slightly increased. By coupling zeta-potential measurements and TEM observations at different pH it appeared that interactions between nanotubes and USPIO were not electrostatic. This study presents the new design of a titanate n…
Magnéli oxides as promising <em>n</em>-type thermoelectrics
2014
The discovery of a large thermopower in cobalt oxides in 1997 lead to a surge of interest in oxides for thermoelectric application. Whereas conversion efficiencies of p-type oxides can compete with non-oxide materials, n-type oxides show significantly lower thermoelectric performances. In this context so-called Magneli oxides have recently gained attention as promising n-type thermoelectrics. A combination of crystallographic shear and intrinsic disorder lead to relatively low thermal conductivities and metallic-like electrical conductivities in Magneli oxides. Current peak-zT values of 0.3 around 1100 K for titanium and tungsten Magneli oxides are encouraging for future research. Here, we …
Fundamental and technological aspects of the surface properties and reactivity of some metal oxides
1997
Abstract As is usually accepted for many inorganic compounds, the surface properties often play a fundamental role in the overall properties of metal oxides, in particular when the oxide materials are used in the form of fine grains. One difficulty in characterizing these surface properties is to apply the results of studies performed on ideal surfaces to the actual materials in use. A way to accept this challenge can be to successively consider initial powders, polycrystalline pellets formed after thermal or mechanical treatment of these powders and, finally, monocrystalline surfaces prepared from these powders or pellets. This principle can be applied to the study of the surface propertie…
Use of pure vanadium and niobium/copper inserts for laser welding of titanium to stainless steel
2020
Abstract Niobium and vanadium have high metallurgical compatibility with titanium and therefore can be used as inserts to avoid the accumulation of brittle intermetallic phases such as Fe2Ti during the fusion welding of titanium alloys with steels. In the present study, the continuous double pass welding of 1 mm thick Ti-6Al-4V alloy and 316 L stainless steel plates through several mm wide pure vanadium or niobium insert was studied. In case of a vanadium insert, a beam offset on the vanadium was found to produce cold crack formation in vanadium/316 L melted zones containing more than 40 wt.% V despite the absence of σ phase. Whereas a centered beam position and offset on the steel side pro…
Dawning of the N=32 shell closure seen through precision mass measurements of neutron-rich titanium isotopes
2018
A precision mass investigation of the neutron-rich titanium isotopes 51 − 55 Ti was performed at TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN). The range of the measurements covers the N = 32 shell closure, and the overall uncertainties of the 52 − 55 Ti mass values were significantly reduced. Our results conclusively establish the existence of the weak shell effect at N = 32 , narrowing down the abrupt onset of this shell closure. Our data were compared with state-of-the-art ab initio shell model calculations which, despite very successfully describing where the N = 32 shell gap is strong, overpredict its strength and extent in titanium and heavier isotones. These measurements a…
Expanding Two-Photon Intravital Microscopy to the Infrared by Means of Optical Parametric Oscillator
2010
Chronic inflammation in various organs, such as the brain, implies that different subpopulations of immune cells interact with the cells of the target organ. To monitor this cellular communication both morphologically and functionally, the ability to visualize more than two colors in deep tissue is indispensable. Here, we demonstrate the pronounced power of optical parametric oscillator (OPO)-based two-photon laser scanning microscopy for dynamic intravital imaging in hardly accessible organs of the central nervous and of the immune system, with particular relevance for long-term investigations of pathological mechanisms (e.g., chronic neuroinflammation) necessitating the use of fluorescent…
Short-range order around Er3+ in silica waveguides containing aluminium, titanium and hafnium
2006
Er3+-doped silica waveguides, co-doped with aluminium, titanium, and hafnium oxides, were prepared using the sol-gel method and dip-coating processing. Here, we present a characterisation of the local environment around Er3+ ions, as determined from the Er L3-edge extended X-ray absorption fine structure (EXAFS) measurements performed at ESRF (France). The first coordination shell is composed of 5-6 oxygen atoms at distances ~2.32-2.35 A , slightly varying as a function of the modifier oxide. Er3+ nearest neighbors distance does not show a significant compositional dependence. On the contrary, outer shells analysis shows significant differences: Al2O3 doping (less than 2% mol) induces an or…
Sample building orientation effect on porosity and mechanical properties in Selective Laser Melting of Ti6Al4V titanium alloy
2022
Abstract In recent decades, the focus of research has shifted towards new production technologies with the aim of optimizing production and reducing costs. These innovative technologies include additive manufacturing processes as Selective Laser Melting (SLM). The analysis of the literature on the identification of optimal building orientation to maximize the mechanical properties and minimize porosity of the final products highlights contrasting results, denoting that the thermomechanical complexity of the process, as associated with the variation of the building orientation, has not been fully clarified. A study in which the building orientation effect was evaluated together with the geom…