Multivariable Intelligent Control for M.A.G. Welding Process

A neural control technique, applied to the MAG (Metal-Active Gas) welding process, is presented in the paper. The static nonlinear model of welding process is based on experimental determinations. The geometric parameters of the welding beam are considered as output parameters of the MAG process (Bs, a, p), and they are measured for different step-variations of the input parameters (Ve, Vs, Ua). The analysis of the output dynamics was further used to model the MAG welding process using a 3- layer neural network with 6 hidden-layer neurons. In order to reject perturbations and cancel the stationary error, an error compensator was used, which consists of the reversedynamic model connected to a proportional integrator controller. imulation results for the multivariable neural controller are presented

Fabrication and Transport Properties of Manganite-Polyacrylamide-Based Composites

We present the fabrication and transport properties of a series of composites made of La2/3Sr1/3MnO3 and acrylamide-based copolymers. The most important result is the very narrow transition, of only 27 K, displayed by the peak that appears around the metal-insulator transition of the composites made with poly(acrylamide-vinylacetate). Although the amount of polymer is rather low, different copolymers change drastically the electric transport characteristics

Photocatalytic activity of pulsed laser deposited TiO2 thin films in N-2, O-2 and CH4

We report on pulsed laser deposition of TiO2 films on glass substrates in oxygen, methane, nitrogen and mixture of oxygen and nitrogen atmosphere. The nitrogen incorporation into TiO2 lattice was successfully achieved, as demonstrated by optical absorption and XPS measurements. The absorption edge of the N-doped TiO2 films was red-shifted up to similar to 480 nm from 360 nm in case of undoped ones. The photocatalytic activity of TiO2 films was investigated during toxic Cr(VI) ions photoreduction to Cr(III) state in aqueous media under irradiation with visible and UV light. Under visible light irradiation, TiO2 films deposited in nitrogen atmosphere showed the highest photocatalytic activity, whereas by UV light exposure the best results were obtained for the TiO2 structures deposited in pure methane and oxygen atmosphere

Aluminum Oxide Ceramic Coatings on 316l Austenitic Steel Obtained by Plasma Electrolysis Oxidation Using a Pulsed Unipolar Power Supply

AISI 316 steel has good corrosion behavior and high-temperature stability, but often prolonged exposure to temperatures close to 700 °C in aggressive environments (e.g., in boilers and furnaces, in nuclear installations) can cause problems that lead to accelerated corrosion degradation of steel components. A known solution is to prepare alumina ceramic coatings on the surface of stainless steel. The aim of this study is to obtain aluminum oxide ceramic coatings on 316L austenitic steel, by Plasma Electrolysis Oxidation (PEO), using a pulsed unipolar power supply. The structures obtained by PEO under various experimental conditions were characterized by XPS, SEM, XRD, and EDS analyses. The feasibility was proved of employing PEO in NaAlO2 aqueous solution using a pulsed unipolar power supply for ceramic–like aluminum oxide films preparation, with thicknesses in the range of 20–50 μm, and a high content of Al2O3 on the surface of austenitic stainless steels

TiO 2 /ZrO 2 THIN FILMS SYNTHESIZED BY PLD IN LOW PRESSURE N-, C-AND/OR O-CONTAINING GASES: STRUCTURAL, OPTICAL AND PHOTOCATALYTIC PROPERTIES

Doped TiO 2 /ZrO 2 films were obtained by Pulsed Laser Deposition method under different synthesis conditions. The onset of absorption spectra was red shifted for the films obtained in N 2 containing gas mixtures, while a broad absorption in visible was observed in the case of films deposited in CH 4 atmosphere. The presence of O-Ti-N bonds revealed by XPS corresponded to the highest photocatalytic performance. XPS spectra of the samples obtained in N 2 /CH 4 gas mixtures evidenced a more effective incorporation of nitrogen in the structure due to oxygen deficiency. Nevertheless, no atomic carbon presence in the TiO 2 /ZrO 2 structures has been detected

Tio2/zro2 thin films synthesized by pld in low pressure n-, c- and/or o-containing gases: structural, optical and photocatalytic properties

Doped TiO2/ZrO2 films were obtained by Pulsed Laser Deposition method under different synthesis conditions. The onset of absorption spectra was red shifted for the films obtained in N-2 containing gas mixtures, while a broad absorption in visible was observed in the case of films deposited in CH4 atmosphere. The presence of O-Ti-N bonds revealed by XPS corresponded to the highest photocatalytic performance. XPS spectra of the samples obtained in N-2/CH4 gas mixtures evidenced a more effective incorporation of nitrogen in the structure due to oxygen deficiency. Nevertheless, no atomic carbon presence in the TiO2/ZrO2 structures has been detected

The Physicochemical and Antimicrobial Properties of Silver/Gold Nanoparticles Obtained by “Green Synthesis” from Willow Bark and Their Formulations as Potential Innovative Pharmaceutical Substances

Green chemistry is a pharmaceutical industry tool, which, when implemented correctly, can lead to a minimization in resource consumption and waste. An aqueous extract of Salix alba L. was employed for the efficient and rapid synthesis of silver/gold particle nanostructures via an inexpensive, nontoxic and eco-friendly procedure. The nanoparticles were physicochemically characterized using ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), X-ray diffraction (XRD) and scanning electron microscopy (SEM), with the best stability of up to one year in the solution obtained for silver nanoparticles without any chemical additives. A comparison of the antimicrobial effect of silver/gold nanoparticles and their formulations (hydrogels, ointments, aqueous solutions) showed that both metallic nanoparticles have antibacterial and antibiofilm effects, with silver-based hydrogels having particularly high antibiofilm efficiency. The highest antibacterial and antibiofilm efficacies were obtained against Pseudomonas aeruginosa when using silver nanoparticle hydrogels, with antibiofilm efficacies of over 75% registered. The hydrogels incorporating green nanoparticles displayed a 200% increased bacterial efficiency when compared to the controls and their components. All silver nanoparticle formulations were ecologically obtained by “green synthesis” and were shown to have an antimicrobial effect or potential as keratinocyte-acting pharmaceutical substances for ameliorating infectious psoriasis wounds