Search results for "Titan"

PMMA-titania nanocomposites: Properties and thermal degradation behavior

2012

Titania nanoparticles were prepared using a solegel method and calcination at 200 and 600 � C in order to obtain anatase and rutile phases, respectively. The obtained powders were used to prepare PMMAe titania nanocomposites by a melt compounding method. The effect of the crystalline phase and the amount of titania, in the range 1e5 wt.%, on the morphology, mechanical properties and thermal degradation kinetics of PMMA was investigated by means of X-ray diffractometry (XRD), transmission electron microscopy (TEM), 13 C cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy ( 13 C{ 1 H}CP-MAS NMR), including the measurement of proton spinelattice relaxation time in t…

Tungstophosphoric acid supported on polycrystalline TiO2 for the photodegradation of 4-nitrophenol in aqueous solution and propan-2-ol in vapour phase

2009

Abstract The present work reports the preparation of samples based on Millennium PC-500 TiO 2 loaded with different amounts of tungstophosphoric acid (up to 30% in weight) and their characterisation by means of different physicochemical techniques: powder X-ray diffraction, N 2 adsorption–desorption at −196 °C, transmission electron microscopy, UV–vis and FT-IR spectroscopies and thermogravimetric analyses. The acidity of samples was evaluated by FT-IR using pyridine as probe molecule, and the catalysts activity was tested for the photodegradation of 4-nitrophenol in aqueous solution and for the photo-oxidation of propan-2-ol in vapour phase. The results show a noticeable improvement (8 and…

Influence of crystallinity and OH surface density on the photocatalytic activity of TiO2 powders

2014

Abstract The aim of the work was to study the influence of crystallinity and OH surface density on the photocatalytic activity of two commercial and two home-prepared TiO 2 powders. The samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG) and electron paramagnetic resonance (EPR) measurements. The photoactivity of the powders was tested employing the photodegradation of 4-nitrophenol (4-NP) and the selective oxidation of 4-methoxybenzyl alcohol (4-MBA) to 4-methoxybenzaldehyde ( p -anisaldehyde) under UV irradiation. An anti-correlation between oxidant power and selectivity of the various samples was found. A higher rate of 4-NP degradation was exhibited by…

Improving the high temperature oxidation resistance of pure titanium by shot-peening treatments

2017

International audience; Shot-peening (SP) treatments have shown their capacity to improve the oxidation resistance of titanium and zirconium thanks to the large compressive stresses and the surface hardening induced by this mechanical process. However, shot-peening treatments can produce a surface chemical deposit, which can modify the high temperature oxidation resistance. Here, we study pure titanium samples shot-peened with different type of balls: tungsten carbide, alumina or glass. The oxidation behavior was studied at 700 °C in dry air by thermo gravimetric analysis for short isotherm oxidation periods up to 100 h. Also, long oxidation tests (3000 h) at 700 °C were performed with an i…

Double traumatic diaphragmatic injury: A case report.

2019

Highlights • Diaphragmatic injuries are rare complications from trauma. • Bilateral diaphragmatic injuries are extremely rare and just a few cases are reported. • Sometimes the diagnosis is delayed or even missed. • Both primary repair or mesh repair are safe and feasible. • The use of a polypropylene mesh with titanized surface has not been attempted before.

COMPUTER AIDED ENGINEERING FOR THERMO-MECHANICAL-METALLURGICAL ANALYSIS OF FORGING OPERATIONS OF TITANIUM ALLOYS

In this thesis a study on the forging processes of Ti-6Al-4V titanium alloy, with particular focus on the numerical applications and simulation design of hot forming methods, was done. The aim of this work is to collect all data concerning the material definition in terms of thermal, mechanical and microstructural properties of the selected alloy in order to filter all useful information to describe the behavior of the material under the characteristic conditions of the hot forging processes, taking into account both thermo-mechanical and metallurgical aspects involved during a such complex thermo-mechanical stage. Those information were collected and used to characterize the material prope…

Toward development of optical biosensors based on photoluminescence of TiO2 nanoparticles for the detection of Salmonella

2017

Quality control of food and agriculture production is an inseparable part of human safety and wellbeing. Salmonella infections belong to one of the most monitored pathogens in the world, therefore advanced determination of this pathogen can decrease the risks of human diseases caused by this microorganism. In this research we introduce a novel optical immunosensor for determination of Salmonella typhimurium. The immunosensor is based on Titanium dioxide (TiO2) nanoparticles deposited on glass substrates (glass/TiO2)center dot TiO2 nanoparticles exhibit an intense photoluminescence (PL) in the visible range of spectrum at room temperature. The direct immobilization of antibodies (anti-S-Ab) …

A study of electron transfer in Ru(dcbpy)2(NCS)2 sensitized nanocrystalline TiO2 and SnO2 films induced by red-wing excitation.

2008

Excited state dynamics and electron transfer from the Ru(dcbpy)2(NCS)2 (RuN3) sensitizer to semiconductor nanoparticles were studied using time-resolved femtosecond absorption spectroscopy. We found that excitation of the red wing of the absorption spectrum of the sensitizer populates the (3)MLCT state directly, both in solution and attached on semiconductor nanoparticle films. Electron injection is slowed down and becomes gradually less efficient as excitation moves towards red from the absorption maximum at 535 nm. At 675 nm the injection is non-exponential and characterized by 5, 30 and 180 ps time constants. The non-exponential electron injection observed is assigned to injection from a…

Promotion of osteogenic cell response using quasicovalent immobilized fibronectin on titanium surfaces: introduction of a novel biomimetic layer syst…

2012

Purpose Despite the undeniable potential of cell adhesion molecules such as fibronectin to support osteogenic cell responses and consecutive dental implant healing, the most beneficial mode of application onto titanium implant surfaces still requires investigation. Unspecific fibronectin adsorption on titanium dioxide (TiO2) surfaces can result in low-loading, high-desorption rates and protein–metal interactions with impaired biologic activity. The aim of the present study was to monitor the osteogenic cell responses (cell adhesion, proliferation, and differentiation) specifically to fibronectin biofunctionalized TiO2. Materials and Methods An innovative biomimetic streptavidin-biotin layer…

Fabrication and Characterisation of Titania Photonic Nanostructures

2015

In this work, we report about the preparation and morphological characterization of photonic nanopatterned titania films (~ 200 nm).