Search results for "Conversion"
showing 10 items of 707 documents
Thermalization and condensation in an incoherently pumped passive optical cavity
2011
International audience; We study theoretically and numerically the condensation and the thermalization of classical optical waves in an incoherently pumped passive Kerr cavity. We show that the dynamics of the cavity exhibits a turbulent behavior that can be described by the wave turbulence theory. A mean-field kinetic equation is derived, which reveals that, in its high finesse regime, the cavity behaves essentially as a conservative Hamiltonian system. In particular, the intracavity turbulent field is shown to relax adiabatically toward a thermodynamic equilibrium state of energy equipartition. As a consequence of this effect of wave thermalization, the incoherent optical field undergoes …
Thermal analysis applied to the characterization of degradation in soil of polylactide: II. On the thermal stability and thermal decompositon kinetics
2010
[EN] The disposal stage of polylactide (PLA) was assessed by burying it in active soil following an international standard. Degradation in soil promotes physical and chemical changes in the polylactide properties. The characterization of the extent of degradation underwent by PLA was carried out by using Thermal Analysis techniques. In this paper, studies on the thermal stability and the thermal decomposition kinetics were performed in order to assess the degradation process of a commercial PLA submitted to an accelerated soil burial test by means of multi-linear-non-isothermal thermogravimetric analyses. Results have been correlated to changes in molecular weight, showing the same evolutio…
An inconvenient influence of iridium(III) isomer on OLED efficiency.
2010
The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. As a consequence, solution processed OLEDs made using a mixture of N984 and isomer N984b similar to vacuum processed devices show that the isomer has a dramatic detrimental effect on the performances of the device. In addition, commonly used thermogravimetric analysis is not suitable for showing the isomerization process. The isomer could impact pe…
Efficient Conversion of Carbon Dioxide by Imidazolium-Based Cross-Linked Nanostructures Containing Polyhedral Oligomeric Silsesquioxane (POSS) Buildi…
2019
Polyhedral oligomeric silsesquioxanes (POSS) have been employed as molecular building blocks for the synthesis of imidazolium cross-linked networks, to be used as heterogeneous catalysts for the conversion of carbon dioxide into cyclic carbonates. Two hybrid materials with different nucleophilic species (bromide and iodide) have been prepared and characterized by means of elemental analysis, 13C and 29Si solid-state NMR spectroscopy, thermogravimetric analysis and IR spectroscopy. The solids were tested as the sole catalyst under metal- and solvent-free reaction conditions showing full selectivity toward the formation of cyclic carbonates. High turnover number (TON) and productivity values,…
Non-isothermal thermogravimetry as an accelerated tool for the shelf-life prediction of paracetamol formulations
2021
Abstract In this work, non-isothermal thermogravimetric studies have been carried out on several paracetamol formulations with the aim to predict their shelf-lives under variable storage conditions. Specifically, paracetamol tablets of different brands have been investigated allowing to estimate their pharmaceutical quality by considering the specific drug stability. The proposed protocol is based on the kinetic study of thermogravimetric data by the combination of isoconversional procedures (Friedman and Kissinger-Akahira-Sunose (KAS) methods) and “Master plot” analysis. Accordingly, the kinetics of the paracetamol degradation is totally explored in terms of activation energy, pre-exponent…
Intracavity Frequency Doubling and Difference Frequency Mixing for Pulsed ns Ti:Sapphire Laser Systems at On-Line Radioactive Ion Beam Facilities
2015
Intra-cavity second harmonic generation of a Titanium:sapphire (Ti:sa) laser system has been used to improve the conversion efficiency to the second harmonic. Over the course of several experiments performance data spanning the whole wavelength range of a Ti:sa has been collected, which may be used as a guideline for future experiments. An average output power of up to 3.7 W was achieved, resulting in a conversion efficiency of >75 % to the second harmonic. A wavelength coverage from 340-525 nm has been demonstrated. To extend the wavelength range of the solid state laser system, difference frequency mixing has been applied to the intra-cavity doubled light and the fundamental output of a s…
TiO2 Photocatalytic glucose conversion to H2 and high value chemicals
2015
In this work it is reported the conversion of glucose in aqueous dispersion of various TiO2 based photocatalysts. Aerobic and anaerobic conditions were used to study the distribution of the products both in the liquid (arabinose, gluconic acid, fructose and formic acid) and gas (H2 and CO2) phases. Commercial and home prepared bare and Pt-supported TiO2 samples were used as the photocatalysts.
Photocatalytic membranes based on TiO2 catalysts and fluorinated polymers for CO2 conversion
2015
In this work, prepared TiO2–Nafion™-based membranes were used in a photocatalytic membrane reactor, operated in continuous mode, for converting CO2 to methanol.
Mixed Harmonic Elimination Control for a Single-Phase 9 Level Grid-Connected Inverter
2018
The power quality requirements are increasingly stringent, due to the continuous growth of devices connected to the grid that introduce harmonics. These devices include DC to AC energy conversion systems, i.e. grid connected inverters. The design, control and operation of these systems must take into account the rules of interconnection to the electricity grid. To improve the quality of the output waveform of the grid-connected inverter, Multilevel Converters (MC) with selective harmonic elimination modulation technique can be used. This paper presents a single-phase nine level grid-connected inverter with DC/DC input stages. The obtained switching angles for THD minimization are independen…
Dietary Conversions and Forms of Life
2019
This paper regards the emergence of forms of life in the field of food and dietary choices. It aims at connecting meat-free diets with the notion of form of life, especially focussing on the moment of “conversion” from an omnivourous diet to vegetarianism or veganism. The semiotic mechanisms of transitions between forms of life connected to dietary regimens will be highlighted. How does the conversion happen? Like in spiritual and religious discourses, the conversion is often a striking event, a punctual episode in the subject’s life, affecting particularly his/her pathemic and sensorial spheres. In other cases, conversions imply complex and slow processes, affecting pragmatic and cognitive…