Search results for "bonding"

Anodic Alumina Membranes for Fuel Cell Technology and Nanostructure Template-assisted Deposition

2009

Anodic alumina membranes (AAMs) with ordered porous structure have been investigated as possible ionic conducting membranes for thin film (= 50μm) fuel cells (TFFC) and as templates for the production of a variety of nanostructure arrays. The aims of this work are to present some of our recent results pertaining to the functionalisation of AAM with proton conductors for the production of membranes to be used in hydrogen/oxygen TFFC, at low or intermediate temperature (25°C ≦ T ≦ 250°C), and to the fabrication by template technique of nanowires/nanotubes arrays of oxide and hydroxides for possible future technological application.

Incorporation of a tricationic subphthalocyanine in an organic photovoltaic device

2013

A new tricationic subphthalocyanine was synthesized and employed as light-harvesting and donor material in an ionic solid state organic photovoltaic cell. The incorporation of ionic dyes in organic photovoltaics aims to take advantage of ionic movement in order to enhance the charge transport properties of these materials. In this preliminary study, we report the results obtained in the fabrication of a partially solution-processed device with a cationic dye, where an effiency of 0.5% was reached.

Transport properties of an ionic magnetic colloid: experimental study of increasing the ionic strength

2002

Abstract The phase separation of an ionic magnetic colloid in zero magnetic field by increasing the ionic strength is well known [Universite Paris VI, France, 1987; J. Colloid Interface Sci. 132 (1989) 1]. The present work deals with investigation of an ionic ferrofluid by increasing the ionic strength in the range of 0–0.14 mol/l, being safely below the threshold value at which the effect of phase separation occurs. By the optical grid setup [Fourth International conference PAMIR, France, 2000], the main transport properties of a ferrofluid, i.e. translational mass diffusion and thermal diffusion (Soret) coefficients, are measured. The obtained results show a strong dependence of mass diff…

Halogen and Hydrogen Bonded Complexes of 5-Iodouracil

2013

Three derivatives of 5-iodouracil were prepared, and their complexation properties, supplemented by 5-iodouracil under the same conditions, were studied with and without halogen bond acceptors in N,N-dimethylformamide, N,N-diethylformamide, N-methylformamide, formamide, dimethylsulfoxide, and water. The intermolecular halogen and hydrogen bonding interactions observed in the solid state were investigated using single crystal X-ray diffraction and quantum chemical calculations, and the acquired data were contrasted with bonding interactions previously reported for 5-iodouracil in the Cambridge Structural Database. It was found that the polarized iodine atom and the amidic NH functionality ac…

The mechanism of formamide hydrolysis in water from ab initio calculations and simulations.

2005

The neutral hydrolysis of formamide in water is a suitable reference to quantify the efficiency of proteolytic enzymes. However, experimental data for this reaction has only very recently been obtained and the kinetic constant determined experimentally is significantly higher than that predicted by previous theoretical estimations. In this work, we have investigated in detail the possible mechanisms of this reaction. Several solvent models have been considered that represent a considerable improvement on those used in previous studies. Density functional and ab initio calculations have been carried out on a system which explicitly includes the first solvation shell of the formamide molecule…

Bonding prediction in friction stir consolidation of aluminum alloys: A preliminary study

2018

Friction Stir Consolidation (FSC) is a solid-state process that results in consolidation of metal powders or chips producing solid billet through severe plastic deformation and the solid-state bonding phenomena. This process can be used both for primary production and for metal scrap recycling. During the FSC process, a rotating die is plunged into a hollow chamber containing the finely divided, unconsolidated material to be processed. In this paper, a FEM numerical model for the prediction of the quality of the consolidated billet is presented. In particular, a dedicated bonding criterion that takes into account the peculiar process mechanics of this innovative technology is proposed.

On the field variables influence on bonding phenomena during FSW processes: experimental and numerical study

2013

Solid state bonding recurs in several manufacturing processes, as Friction Stir Welding (FSW), Linear Friction Welding (LFW), extrusion of hollow profiles and Accumulative Roll Bonding (ARB). The former processes are nowadays of particular industrial interest because of the specific advantages with respect to the classic welding technologies. In FSW the solid state bonding is obtained between an undeformed “cold” material, already placed in the advancing side of the joint, and the “hot” material flow incoming from the retreating side. Proper conditions of pressure, temperature, strain and strain rate are needed in order to get the final effective bonding. In the paper experimental tests on …

Friction based solid state welding processes

2012

Interface engineering in efficient vacuum deposited perovskite solar cells

2016

Abstract We studied the effect of the charge transport layers in p-i-n perovskite solar cells using vacuum deposited methylammonium lead iodide thin-film absorbers. While solution-processed perovskite films are frequently deposited directly on PEDOT:PSS leading to good solar cell performances, in some cases even to very good Voc values, we show that in devices employing vacuum deposited MAPbI3 perovskites, the removal of the polyTPD electron blocker substantially reduces the photovoltaic behavior. This is indicative of rather different charge transport properties in the vacuum deposited MAPbI3 perovskites compared to those prepared from solution. On the other hand, we investigated the use o…

Molecular recognition of nucleotides in water by scorpiand-type receptors based on nucleobase discrimination.

2014

Abstract: The detection of nucleotides is of crucial impor-tance because they are the basic building blocks of nucleicacids. Scorpiand-based polyamine receptors functionalizedwith pyridine or anthracene units are able to form stablecomplexes with nucleotides in water, based on coulombic,p–p stacking, and hydrogen-bonding interactions. This be-havior has been rationalized by means of an explorationwith NMR spectroscopy and DFT calculations. Binding con-stants were determined by potentiometry. Fluorescencespectroscopy studies have revealed the potential of these re-ceptors as sensors to effectively and selectively distinguishguanosine-5’-triphosphate (GTP) from adenosine-5’-triphos-phate (ATP…