A method for obtaining of amorphous aluminium ammonium phosphates is developed. The statistical program STATISTICA 9 is used for planning and evaluation of the experiments. Research is carried out according to the Box-Behnken model for the following values of independent variables (input factors): pH: 6.0 ± 2; concentration of reagents: 40 ± 10 wt%, molar ratio of NH4 +:PO4 3- in substrates (2 ± 1:1) i.e. Al3+:NH4 +:PO4 3- (0.66:1-3:1). On the basis of this research, process parameters are determined, in which materials with the expected physicochemical properties (chemical composition, specific surface area, oil absorption number) can be obtained.

Some human activities can focus radioactive natural materials on their waste and products through technological processes by increasing the local background radioactivity at values that may compromise the health and safety of persons and the environment. The oil industry waste containing technologically enhanced naturally occurring radioactive materials (TENORM) are high volume and low levels activity cannot be classified and arranged according to the Brazilian standard for classification of waste generating a stalemate in its management in Brazil. This work has identified technological alternatives for the disposal of waste containing TENORM available in the world and examined its use in the oil industry in Brazil, considering the Brazilian legislation.

By using the citrate reduction procedure we have synthesized Ag nanoparticles, applying several conditions of preparation, being after characterized by UV-visible spectrophotometry. Following a logical sequence, the starting experiment was realized varying the reaction time, after that it was varied the concentration of the reductor agent, and finally it was varied the volume of the reductor agent. According to this methodology, TEM measurements show that firstly we have nanostructures with different shape and size, whereas in the last part of the experiment we have Ag nanoparticles with homogeneous shape and size.

Steel–magnesium alloy laminated composites can be produced by gas-driven pressure infiltration of a molten magnesium alloy between layers of stacked steel sheets followed by directional solidification of the infiltrated magnesium alloy. A key step in the process is ensuring adequate separation and alignment of the steel sheets during the process; this is achieved by introducing small dimples in the steel sheets to hold them apart during infiltration. Advantages of the process are its speed, the defect-free composites it produces, and the fact that, unlike roll-bonded composites, the steel in the composite is in an annealed condition. The ultimate tensile strength of the as-cast laminates, of 260 MPa, obeys the rule of mixtures. The uniform tensile elongation, of around 20%, makes the infiltrated laminates nearly as ductile as the bulk steel it contains, implying that the magnesium alloy in the as-cast laminates has a substantially increased tensile ductility in comparison to the bulk state in a metallurgically equivalent condition.

The atomic layer deposition (ALD) of SrO was conducted on various oxide surfaces by using strontium bis(tri-isopropylcyclopentadienyl) and water at deposition temperatures of 200 and 250°C. The initial and steady growth behaviors were studied by in-situ spectroscopic ellipsometry and ex-situ X-ray photoelectron spectroscopy. For initial growth, the growth per cycle (GPC) of SrO not only depends on the concentration of hydroxyl groups but also the formation of interfacial Sr-O-Si bonds. For the steady growth, in-situ annealing was used to enhance the growth rate and multiple growth regions were identified.

In this contribution, we study the increase in metalorganic-low pressure chemical vapor deposited (MO-LPCVD) ZnO thin films conductivity by hydrogen plasma post-treatment. We show that this improvement is linked to defect passivation at grain boundaries, decreasing the electron traps density and resulting in the almost complete suppression of the electron scattering at grain boundaries. For a 2 μm thick non-intentionally doped ZnO layer, electron mobility reaches after treatment values close to 60 cm2V-1s-1 (corresponding to an increase of 100%), with a carrier density still as low as 3 x1019 cm-3 (+1.5 x1019 cm-3). Such layers have an absorbance below 2-3% in the range of 400 to 1100 nm making them among the most transparent and conductive materials reported so far. In addition, we demonstrate that hydrogen plasma post-treated ZnO layers can be used as front electrode for producing highly transparent and conductive electrodes. Eventually, it is shown that hydrogen plasma treatment can also be used on the complete thin film solar cell stack (back contact and silicon device) to improve the cell performances.

In order to observe the structural change in the interior of irradiated fuel assembly, the non-destructive post irradiation examination technique using X-ray computer tomography (X-ray CT) was developed.

In this X-ray CT system, the 12 MeV X-ray pulses were used in synchronization with the switch-in of the detector in order to minimize the effects of the gamma ray emissions from the irradiated fuel assembly then clear cross section CT image of irradiated fuel assembly could be successfully obtained. Also, this non-destructive technique can be applied to observe the inner condition of the high radioactive materials such as a radioactive waste.

Sample of zirconate ceramic with a composition corresponding to formula Gd1.7 241Am0.3Zr2O7 was synthesized by heat-treatment of mechanically activated and compacted in pellet oxide mixture at 1500 °C for 30 min. The d values on XRD pattern of the sample soon after synthesis (D = 7.9×1015 α-decays/g or 0.001 dpa) demonstrated fluorite structure with the most intensive peak with d 111 =3.042 Å (a = 5.269 Å) and very weak diffuse reflections due to d-pyrochlore. At a dose of 7.9×1017 α-decays/g or 0.11 dpa the reflections were broadened by approximately 20% and their relative intensity slightly reduced. At higher doses all the weak superstructure reflections disappeared and the growth in intensity and narrowing of the main reflection occurred. Lattice parameter a increased with the dose and reached 5.343 Å (d 111 = 3.085 Å) at a dose of 4.6×1018 α-decays/g or 0.42 dpa. At a dose of 5.5×1018 α-decays/g or 0.78 dpa positions of reflections were shifted to lower d-spaces (d 111 value reduced to 3.071 Å) and the half-width of the major reflection was 67% of initial. For the 241Am-doped Gd-zirconate the structure recovery rate exceeds disordering rate and no amorphization occurred at doses higher than ∼0.2-0.3 dpa.

Thermoelectric properties of the Li-doped Cu0.95-x M0.05Lix O (M=divalent metal ion; Mn, Ni, Zn) were investigated at the temperature up to 1273 K. In the doped divalent metal ions, Zn2+ ion was the most effective to reduce the thermal conductivity, and the Ni2+ substitution was preferable to decrease the electrical resistivity. For the Cu0.95-x Ni0.05Lix O sample at x=0.03, the maxima of the dimensionless thermoelectric figure of merit ZT and the power factor P at 1246 K were 4.2×10-2 and 1.6 ×10-4 W/K2m, respectively. The enhancement of the thermoelectric properties of the Li-doped Cu0.95-x M0.05Lix O system was discussed.

In this work, we demonstrate a new density modulated multilayered silicon thin film anode approach that can provide a robust high capacity electrode for Li-ion batteries. These films have the ability to tolerate large volume changes due to their controlled microstructure. Silicon films with alternating layers of high/low material density were deposited using a DC sputtering system. Density of the individual layers was controlled by simply changing the working gas pressure during sputtering. Samples of Si films having thicknesses of 460 nm with different number of high/low density layers have been deposited on Cu current collectors. The electrochemical performance of the multilayered anode material was evaluated using a galvanostatic battery testing system at C/10 rate. After reaching a stabilized phase the battery cell showed a high coulombic efficiency of 96% to 99% and reversible specific capacity of 666 mAh g-1 (after 100 cycles). Low-density layers are believed to be acting as compliant sheets during volume expansion making the films more durable compared to conventional Si film anodes. The results indicate that density modulated multilayer Si thin films can be used to improve the mechanical properties of Li-ion battery anodes leading to high reversible capacity values even after high number of cycles.

Emission spectroscopy analysis was used to study the microplasma phenomena. The microplasma discharge in Ar, N2/Ar and O2/Ar was analyzed in the discharge gap area and spatial distribution of active species was measured also outside the electrodes. Spatial and temporal distribution showed the propagation of light emission from anode towards cathode within a time period of 190 ns. The measurement of OH peak at 308.9 nm proved the existence of this excited species 1 mm outside the electrodes area.

We present a numerical study on effect of temperature on the performance of a waveguide luminescent solar concentrator (LSC). The purpose is to determine how changes in temperature of the ambient environment of an LSC affect device performance. The thermo-optical coefficient of the polymer waveguide is modeled using the well known Prod’homme formulation and applied in a forward Monte Carlo ray-tracing simulation. We show that the number of collected photons decreases almost linearly as the ambient temperature increases from -50 ºC to +50ºC. This behavior is associated with several competing loss mechanisms in the waveguide. For example, increases in optical confinement due to increased refractive index at low temperature are opposed by increases in cone loss (escape loss) of photons. Other competing mechanisms that exhibit temperature dependence are explained in terms of a detailed balance treatment of the LSC as a function of temperature.

The radiation-induced displacement damage in yttrium borate (YBO3) is studied under X-ray, proton, and alpha irradiation. The photoluminescence (PL) was tested before and after irradiation to determine whether damage occurred and whether it could be queried by examining the PL spectrum. Two different dopants (cerium and europium) were used to activate the phosphor because each provides not only a different spectral signature but also a different mechanism for altering the spectrum between the pre- and post-PL measurements. X-rays, being primarily ionizing radiation, did not show any significant change between the pre and post measurements. We expected protons and alphas to damage the crystal structure, evidence of which could be seen in the change in the spectra before and after irradiation. However, we found no change under alpha exposure (3.6 × 1010 particles/cm2) and a significant change after proton exposure (5 × 1015 particles/cm2). While the material appears to be sensitive to protons, we cannot rule out its sensitivity to alphas because the alpha fluence may be too low to show an effect. This result provides strong indication that our materials are being damaged by particle radiation and that the radiation effects can be quantified.

Concepts for the disposal of high-level radioactive waste (HLW) and spent fuel (SF) in several countries include a massive steel overpack within a bentonite buffer. In past conservative safety assessments to demonstrate feasibility of geological disposal, overpacks are assumed to provide complete containment for a given lifetime, after which all fail simultaneously. After failure, they are ignored as physical barriers to radionuclide transport. In order to compare different repository designs for specific sites, however, a more realistic treatment of overpack failure and its subsequent behaviour is needed. In addition to arguing for much longer lifetimes before mechanical failure and a distribution of overpack failure times, such assessment indicates that the presence of the failed overpack greatly constrains radionuclide release from the waste matrix and subsequent migration through the engineered barrier system. It also emphasises the key role of the bentonite buffer and the need to be able to assure its performance over relevant timescales.

Within the last decades, inkjet printing technology has developed from only a text and graphic industry to a major topic of scientific research and R&D. Inkjet printing can be used as a highly reproducible non-contact patterning technique to print at high speeds either small or large areas with high quality features; it requires only small amounts of functional materials, which immediately favors production costs. Furthermore, inkjet printing reduces the amount of processing steps due to its additive technique of materials deposition, which further decreases productions costs as well as time.

This contribution provides a number of alternative approaches to sinter inkjet printed metal precursor materials at temperatures that are compatible with cost-effective polymer foils. The prepared features can serve as interconnects and contacts for microelectronic applications, such as OLED and OPV.

Three-dimensional numerical simulations can provide information which cannot be obtained from experiments and can be a powerful tool for investigating reaction phenomena in solid oxide fuel cell (SOFC) electrodes. In the present study, a dual-beam focused ion beamscanning electron microscope is used to reconstruct the three dimensional microstructures of the SOFC electrodes, and their polarization characteristics are predicted by a lattice Boltzmann method. Predicted overpotentials for Ni-YSZ anode and mixed ionic and electronic conducting cathode (La0.6Sr0.4Co0.2Fe0.8O3-δ; LSCF6428) are compared with the experimental data for validation. In addition, three-dimensional distributions of electrochemical potential and current densities inside the electrode microstructures are obtained. Large non-uniformities of potential and current distributions are found in the Ni-YSZ anode, while those became much uniform in the LSCF cathode. The present method can be expected as a powerful tool for investigating local potential fields which affect local reactions and diffusion processes as well as local physical properties of the SOFC electrodes.

This paper describes the implementation of a custom-made bio-microelectromechanical system for determining mechanical properties of biological cells, which is used for the measurement of mechanical properties of fibroblasts. Our system consists of several subcomponents: (a) actuator which deforms the cell in pre-determined, step-wise fashion, (b) force sensor that measures force applied onto the cell, (c) set of dielectrophoretic (DEP) electrodes for positioning cells in the desired position, (d) temperature sensors and (e) heater. Preliminary results of the mechanical properties of NIH3T3 cells have been determined using this tool and our cell compression techniques.

Laser irradiation of Bismuth thin films through a diffractive mask was investigated. The thin films were composed of nano and microcrystals Bismuth with sizes ranging from 20 to 500 nm. Upon laser irradiation (λ=355 nm) the structured illumination field locally modified the material. In the high intensity regions the surface was transformed whilst low intensity areas were left intact. The modification mechanism was melting followed by coalescence of the nanocrystals giving rise to a more uniform structure. The laser irradiated area was characterized by scanning electron microscopy and atomic force microscopy. The patterns were computed by Fresnel diffraction theory and the agreement between the theory and the experiments was very good.