Structural properties of liquid and amorphous Al2O3.2SiO2 (denoted as AS2) have been studied in a model containing 3025 particles under periodic boundary conditions with the Born-Mayer type pair potentials. Models have been obtained by cooling from the melt via molecular dynamics (MD) simulation. Structural properties of an amorphous model obtained at the temperature of 350 K have been analyzed in details through the partial radial distribution functions (PRDF), coordination number distribution, bond-angle distributions and interatomic distances. Calculations show that calculated data agree well with the experimental ones and with those obtained previously in other simulation works. The evolution of structure upon cooling from the melt was observed and discussed. We found a clear evidence of the existence of triclusters in the system. Diffusion constant of particles has been calculated and discussed. Calculations presented that the temperature dependence of diffusion constant D of components in the system shows an Arrhenius law at temperatures ranged from 2450 K to 4200 K and it shows a power law, $D\propto (T-T_C )^\gamma$ , at higher temperatures.

Composite films containing silver nanoparticles embedded in diamond-like carbon (DLC) matrix were deposited on glass substrates by using capacitatively coupled plasma (CCP) chemical vapour deposition techninique (CVD). Particle size and metal volume fraction were tailored by varying the relative amount of methane of a gas mixture of methane + argon in the plasma. Optical constants of the films were evaluated. Bonding environment in these films were obtained from Raman and FTIR studies. Blue-shift of the surface plasmon resonance peak in the optical absorbance spectra of the films could be associated with the reduction of the particle size while red shift was associated with the increase in volume fraction of metal particles. The experimental results have been discussed in light of the existing Mie theory.

A numerical study is made of the bandwidth to thickness ratio of radar absorbers for the suppression of normally incident waves. The study deals with single- and multi-layer dielectric absorbers, in which the frequency dispersion of the permittivity is allowed for. Analysis of the results permits obtaining a simple empirical relationship between thickness, bandwidth, and reflectance level of some specific kinds of absorbers. Essential features of different designs of dielectric radar absorbers are revealed and discussed.

In this study, the efficiency of different types of pulsed electrical discharges for the removal of organic pollutants from wastewater has been determined. Three discharge types, either in the water volume or in close proximity to the water surface are studied. The production of hydrogen peroxide in pure water, and the degradation of two typical pollutants (4-chlorophenol and 4-nitrophenol) is measured together with the amount of electrical energy dissipated in discharges. It is shown that the energy yield for the degradation of organic pollutants, expressed in terms of degraded moles per Joule, strongly depends on the discharge type. The highest efficiency is obtained with pulsed corona discharges in humid air above the water surface. A lower efficiency is found with spark discharges in water, and the less efficient process is constituted by streamer discharges in water. The influence of ferrous ions added to solutions is also very different according to the discharge type. This helps to get a better understanding of the degradation processes involved with the different discharge types.

One of the important parameters in understanding the mechanism of the early stage of organic thin-film growth is the critical nucleus size i*. Here, submonolayer films of para-sexiphenyl grown on amorphous silicon dioxide substrates were investigated by means of atomic-force microscopy and have been analyzed using the recently proposed capture-zone scaling. Applying the generalized Wigner surmise we determine from the capture-zone distribution i* at room temperature and 373 K. The results are compared to traditional analysis by island-size scaling and the applicability of the capture-zone scaling is critically discussed with respect to island shape.

Dielectricthin-film helicoidal bianisotropic mediums (TFHBMs)are rotationally nonhomogeneous nano-engineered materialsof recent vintage. Here,optical signatures of axially excited TFHBM slabsare calculated after solving a boundary value problem,after assuming the chosenmaterials to have single-resonance Lorentzian dielectric response properties.The spectrum of co- and cross-polarized reflectancesand transmittances, true and apparent circular dichroisms, trueand apparent linear dichroisms, ellipticity transformation,and optical rotation are presented. The role of the structural period in thespectral location of the circular Bragg phenomenon isdelineated, and measures to deepen thatphenomenon are discussed. The effects ofstructural handedness on the spectrum are also identified.

Removal of molecular atmospheric pollutants by non-thermal plasmas is under study since the beginning of the eighties. It has been shown that pulsed electrical discharges, such as dielectric barrier or corona discharges, are powerful means to eliminate Volatile Organic Compounds (VOCs) from the ambient air, or to treat flue gases which contain nitrogen oxide. However it is now recognised that, for several pollutants, the use of the plasma alone does not allow a complete elimination of the undesirable molecule. For example NO is oxidised in the air plasma to form other oxides like NO2 and N2O5, and reactions of oxygen atoms or hydroxyl radicals produced by the discharge with VOCs can lead not only to H2O and CO2 but to a number of by-products following the partial oxidation of the molecule, which can be as undesirable than the compound to be initially removed from effluents. This is particularly the case when the electrical energy deposited in the gas flow must be kept as low as possible in order to design a low energy cost equipment. As a result addition of a catalyst together with the pulsed discharge is now investigated in various laboratories in order to achieve a complete oxidation of VOCs, i.e. the so-called de-COV process, or a complete reduction of NOX (NO and NO $_{2})$ to produce N2 and O2, i.e. the so-called de-NOX process, at low energy consumption. This paper is a short review of works which have been done these last years in that domain, specifically on NOX and some selected VOC molecules.

Nanocrystalline PbSe films were grown on GaAs(100) and on the As face of GaAs(111) substrates using chemical solution deposition. The microstructure of the films was found to be strongly affected by the deposition temperature over a surprisingly narrow temperature range. In PbSe deposited on GaAs(100), gradual increase in crystallite size and transition to $\langle$ 111 $\rangle$ texture were obtained with increasing temperature. In contrast with PbSe deposited on GaAs(100), the $\langle$ 111 $\rangle$ texture in PbSe on GaAs(111) dominated throughout the deposition temperature range. Since temperature directly affects reaction rate, the temperature-dependent morphological changes observed in this work occur primarily due to increasing sample thickness.

The presence of materials with a relative large difference in permeability has a harmful influence on the convergence of Krylov subspace iterative solvers. Some slow converging components are not cured by preconditioning and correspond to eigenvectors reflecting the domains with relatively low permeable material. Approximations for those eigenvectors are determined using physical knowledge of the problem. The iterative solution process is split up in a small problem counting for the separated eigenmodes and a full-size problem out of which the slow converging modes are removed. This deflated preconditioned solver is faster converging compared to more common approaches, such as the incomplete Cholesky conjugate gradient method.

We have fabricated and characterised colloidal silver nanoparticles by the electrical arc discharge method in DI water. Size and optical properties of the silver nanoparticles were studied versus different arc currents. Optical absorption indicates a plasmonic peak at 392 nm for 10 A which increases to 398 nm for 20 A arc current. This reveals that by raising the arc current the size of the nanoparticles increases. Optical absorption of silver nanoparticles after 3 weeks shows precipitation of them in a water medium. The effect of different surfactant and stabilizer concentrations such as cethyl trimethylammonium bromide (CTAB), polyvinyl pyrrolidone (PVP), sodium citrate, sodium dodecyl sulfate (SDS), sodium di-2-ethylsulfosuccinate (AOT) and carboxymethyl cellulose (CMC) on the stability of silver nanoparticles was investigated. The colloidal silver nanoparticles with 100 μM concentration were stable for more than 3 months at 50 μM CTAB and 6 months at 10 μM sodium citrate concentration, respectively. SEM images of the sample prepared at 50 μM CTAB concentration reveal uniform and fine nanoparticles. The mean size from TEM images is about 14 nm. TEM images of the sample prepared at 10 μM sodium citrate concentration show a shell of citrate that covers the silver nanoparticles.

Recombination processes in GaAsN, GaInAsN, and GaAsSbN compounds have been analysed and compared. The following properties like: broad photoluminescence band at energy of ~ 0.85 eV, an emission band aproximately 80 meV below band gap energy, and annealing-induced blue shift of the energy gap have been found for all three compounds. In order to explain these features a simple band gap diagram with N defect-related levels close to conduction band edge and fluctuations in the energy of the conduction band minimum has been proposed.

Cobalt doped ZnO nanoparticles were synthesized by microwave irradiation technique for their structural and magnetic properties. Initially the samples were exhibit single phase standard ZnO wurtzite structure (x ≤ 0.1) further Co concentration increase Co3O4 phase was confirmed by X-ray diffraction analysis. The average crystallite sizes of cobalt doped ZnO particles were calculated by Debye-Scherrer formula and are nearly 25 nm. The hexagonal wurtzite structure of ZnO and destroyed cubical Co3O4 were identified in the TEM images. The presence of metal oxide was confirmed by Fourier transform infrared spectral analysis result. The micro-Raman analysis confirmed the existence of Co3O4 phase. Magnetization measurements performed by using vibrating sample magnetometer determine the paramagnetic behavior for the synthesized samples.

PbO-Sb2O3-B2O3 glasses containing different concentrations of MoO3 ranging from 0 to 5 mol % were prepared. A number of studies have been carried out on these glasses comprising differential thermal analysis, infrared and optical absorption, Raman and ESR spectra, magnetic susceptibility and measurements of dielectric properties (constant ε′, loss tan δ and a.c. conductivity $\sigma_{ac}$ over a range of frequency and temperature) of these glasses. The results have been analyzed in terms of different oxidation states of molybdenum ions. The analysis indicates that when the concentration of MoO3 is ≤0.6 mol %, molybdenum ions exist mostly in the Mo6+ state, occupy network forming positions with MoO $_{4}^{2-}$ structural units and increase the rigidity of the glass network. When MoO3 is present in higher concentrations, molybdenum ions seem to exist mostly in the Mo5+ state and occupy modifying positions.

We have fabricated heterojunction solar cells comprising active layers of perylene diimide (PDI) or perylene bisbenzimidazole (CONPER, conjugated perylene dye) as electron acceptor and ZnPC as donor. Bilayer solar cells were produced by successive evaporation of zinc phthalocyanine (ZnPC) and perylene diimide (PDI) or perylene bisbenzimidazole (CONPER) on glass substrates coated with indium doped tin oxide. Active layers with different thickness were evaporated. The bilayer cells were characterized under simulated AM 1.5 illumination (100 mW/cm2). The best results were obtained for the device structure of ITO/PEDOT/ZnPC (40 nm)/perylene bisbenzimidazole (60 nm)/Al (70 nm).

A numerical integration scheme is presented for integration of the pressure-sensitive yield criterion due to Gurson, suitable for explicit dynamic finite element calculations. This scheme utilizes a sub-increment approach to Mayntain stability for the large strain increments and intense triaxiality that can occur under high strain rate loading. A number of validation problems are presented after which two laboratory-scale high strain experiments are simulated. The integration scheme is shown to be stable and to capture the onset of tensile fracture under high strain rate loading conditions.

Using phenol as a model organic pollutant we studied and characterized an innovative advanced oxidation process in water using a prototype dielectric barrier discharge (DBD) reactor in which electrical discharges are produced in the air above the water surface. Phenol is decomposed quite efficiently in this reactor operated at room temperature and atmospheric pressure. The process selectivity to form CO2 is, however, to be improved since a large fraction of the treated organic carbon is unaccounted for. The rate of phenol conversion increases linearly with the reciprocal of the pollutant initial concentration, suggesting the operation of a mechanism of inhibition by products as found earlier for oxidation of volatile organic pollutants in air plasmas.

Hematite particles have been synthesized by a one step thermohydrolysis of nitrate iron (III) solutions. The microwave system (RAMO system) designed by the authors is able to induce very fast heating rates within an autoclave. These operating conditions induce precipitation reactions in the entire volume of the reactor. These precipitation conditions lead to instantaneous nucleation of monodisperse particles (separation of the nucleation and growth events). These results indicate that it should be possible to produce very well-crystallized hematite particles which can be used as precursors for production of magnetite or maghemite.

Tin sulphide films have been deposited onto glass substrates at room temperature by chemical bath deposition using aqueous solution. The structural and vibrational properties of the deposited films have been characterized by X-ray diffraction (XRD), FT-IR and Raman spectroscopy. XRD data indicate that as grown film is polycrystalline in nature and is composed of predominantly orthorhombic phase. Infrared spectrum of the film has been investigated in 4000–400 cm−1 region. The infrared spectrum of SnS displays several bands. The Raman spectrum studies revealed three peaks (64, 106 and 239 cm-1) of SnS film. The spectrum analysis also shows that there exists a Sn2S3or/and SnS2 phase in the deposited film.

X-ray photoelectron spectroscopy (XPS) and cathodoluminescence (CL) method have been employed to study the chemical composition and the oxygen vacancy concentration of HfO2, Sc2 O3 and (HfO2)1−x(Sc2O3)x films. It was found that the increase of Sc content led to monotonic decreasing the Hf4f7/2 and Sc2p3/2 binding energies indicating to form solid solution (HfO2)1−x(Sc2O3)x. All the samples characterized by the intensive CL spectra with maximum around 3 eV which originated due to some radiative recombination emission caused by oxygen deficiency. The concentration of oxygen vacancy in the Sc-doped HfO2 is sensitive to the Sc content and as a result the intensity of CL spectra of (HfO2)1−x(Sc2O3)x is lower that those of pure HfO2 and Sc2O3.

In order to reduce the computation time of a quasi-static problem solved by the finite element method, methods of model order reduction can be applied. In this context, two approaches, the proper orthogonal decomposition and the proper generalized decomposition, are applied to the vector poten-tial formulation used to solve the quasi-static problem. The developed methods are compared on an academic example.