Electrodeposition of nanostructured cuprous oxide on various substrates and their electrochemical and photoelectrochemical properties

Journal of Materials Science: Materials in Electronics - Nanostructured Cu2O films have been developed on various conductive substrates (FTO, ITO, and Mo) by a low-cost electrodeposition process...     

DNA detection with a water-gated organic field-effect transistor

A DNA sensor based on a water-gated organic field-effect transistor is described. The semiconductor is poly [3-(5-carboxypentyl)thiophene-2,5-diyl] onto which DNA probes are covalently grafted via NHS/EDC chemistry. Clear changes in the output characteristic of the device are observed upon DNA immobilization and after DNA hybridization. Experimental data point out the importance of the electrolyte Debye length that can screen negative DNA charges and impede transduction. For this reason, deionized water was used in order to increase the Debye length up to several hundreds of nanometers. In this case, a decrease in the off current was observed upon hybridization, whereas no significant change occurred when using saline solutions.     

Novel dynamic color image watermarking based on DWT-SVD and the human visual system

Multimedia Tools and Applications - In this paper, a novel dynamic color image watermarking based on discrete wavelet transform (DWT) and singular value decomposition (SVD) is proposed. The...     

Eikonal-based region growing for efficient clustering

We describe an Eikonal-based algorithm for computing dense oversegmentation of an image, often called superpixels. This oversegmentation respects local image boundaries while limiting undersegmentation. The proposed algorithm relies on a region growing scheme, where the potential map used is not fixed and evolves during the diffusion. Refinement steps are also proposed to enhance at low cost the first oversegmentation. Quantitative comparisons on the Berkeley dataset show good performance on traditional metrics over current state-of-the art superpixel methods.     

Multiple glass transition temperatures of polymer thin films as probed by multi-wavelength ellipsometry

Ellipsometry was used as a technique to determine glass temperature transitions of homopolymer thin films of polystyrene and poly(methyl methacrylate) ranging from 5 to 200 nm. The technique operated systematically at various energies reveals the presence of multiple transitions in these films under certain conditions of preparation. It was observed that in the case of strong polymer-substrate interactions, several Tg were measured and ascribed to a layered structure in the film. In the absence of strong interactions, a more uniform film presenting a single Tg was observed no matter the thickness. The results confirm the recent assumption of thin films organised in multilayers and emphasize the importance of using a highly sensitive multi-wavelength technique in probing such properties.     

WEBEXPIR: Windowless target electron beam experimental irradiation

The windowless target electron beam experimental irradiation (WEBEXPIR) program was set-up as part of the MYRRHA/XT-ADS R&D effort on the spallation target design to investigate the interaction of a proton beam with a liquid lead-bismuth eutectic (LBE) free surface. In particular, possible free surface distortion or shockwave effects in nominal conditions and during sudden beam on/off transient situations, as well as possible enhanced evaporation were assessed. An experiment was conceived at the IBA TT-1000 Rhodotron, where a 7 MeV electron beam was used to simulate the high power deposition at the MYRRHA/XT-ADS LBE free surface. The geometry and the LBE flow characteristics in the WEBEXPIR set-up were made as representative as possible of the actual situation in the MYRRHA/XT-ADS spallation target. Irradiation experiments were carried out at beam currents of up to 10 mA, corresponding to 40 times the nominal beam current necessary to reproduce the MYRRHA/XT-ADS conditions. Preliminary analyses show that the WEBEXPIR free surface flow was not disturbed by the interaction with the electron beam and that vacuum conditions stayed well within the design specifications.     

Kinematic model identification of industrial manipulators

The aim of the work presented in this paper is to improve the off-line programming capability of industrial robots by improving their accuracy. Rather than impose more strict manufacturing tolerances, it is widely accepted that a method of identifying kinematic parameters specific to each individual robot provides a cost effective way of improving accuracy. A procedure is presented for identification of actual kinematic parameters, which uses the plane of rotation and centre of rotation introduced by Stone. The procedure differs from that of Stone in that it makes use of the radius of rotation and also introduces a translation of the plane of rotation along the axis of rotation. This allows for the direct identification of the D–H model parameters which are more widely accepted and easier to interpret than the S model parameters. It is shown that, unlike the original method of Stone, the new procedure can also deal with the situation when two consecutive joint axes are parallel. The method is validated on both simulated data and real measured data for a Puma 560 robot, showing an improvement in positioning accuracy of around 80%.     

Natural convection cooling process from two identical porous-covering electronic components

In the present work, we focus to study numerically the natural convection cooling process from two identical electronic components located on the bottom wall of a two-dimensional cavity. Each electronic component is covered by a porous medium with finite thickness. The conservation equations governing the problem are discretized using the finite volume method and the SIMPLER algorithm is used to handle the nonlinear character of conservation equations. Calculations were carried out for the following control parameters: the porous/fluid thermal conductivity ratio (1 ≤ Rk_P1 ≤ 100), the Darcy and Rayleigh numbers (10⁻¹ ≤ Da ≤ 10⁻⁶, 10³ ≤ Ra ≤ 10⁶), the first porous-cover thickness (0.05 ≤ e₁ ≤ 0.3), and the separation distance between components (0.2 ≤ S ≤ 1) to highlight their influence on the cooling process. The results show that under specific values of the Darcy and Rayleigh numbers and in the limiting case of a high value of the porous/fluid thermal conductivity ratio (Rk_P1 = 100), a decrease in the maximum components temperature, up to 95%, is observed by increasing the porous-cover thickness from 0.05 to 0.3. In addition, by increasing the permeability, the Rayleigh number or the separation distance, an improvement in the cooling process of the two components greater than or equal to 22% is achieved.