Polymer solar modules, based on glass or flexible PET-substrates, structured either by laser ablation, mechanical scribing, or by a combination of the two, were prepared and analyzed. The photo-active layer of the solar modules is based on poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester or Poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]:phenyl-C71-butyric acid methyl ester donor-acceptor bulk heterojunctions. Since such polymer-fullerene solar cells and modules are designed in a multilayer architecture, local defects such as shunts or blocking junctions in the device can cause critical losses to the solar module performance. Of special importance for solar module preparation is the structuring process, as it allows the serial interconnection of the cells. The high precision required for removing neither too few nor too much of the thin layers to be structured presents challenges in the processing of polymer solar modules. Herein we demonstrate that laser structuring is a suitable technology to face these challenges. We report about completely or partially laser structured polymer photovoltaic modules. By using highly sensitive dark lock-in thermography we analyze the influence of defects and failures on the performance and operation of solar module devices. Finally, promising results for fully laser structured solar modules on glass and partly laser structured solar modules on PET are presented.

The scaffold is obtained from acellular bovine bone: Nukbone® (produced by Biocriss SAPI de CV). This acellular bone was subjected to a demineralization process after which the composition was found to be 10% water, 65% of collagen and 25% of hydroxyapatite. The techniques used to characterize these natural scaffolds were: optical microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, thermo gravimetric analysis, differential scanning calorimetry and determination of pore size using nitrogen adsorption, and physical adsorption of N2. The pore size is between 100 and 500 microns. These scaffolds have been tested in several biological tissues as urethra, trachea, blood vessels, bone and heart successfully.

Silver nanoparticles (AgNPs) in silicate clay matrix films were fabricated from solution casting method. The Ag/clay dispersion was first prepared from in situ reduction of silver nitrate in the presence of silicate clay platelets and ethanol as the reducing agent. The morphologies of AgNPs have changed in a hierarchical manner, from sphere to cube and then to rod and wire morphologies during the annealing at 200 °C. The originally homogeneous AgNPs distribution in the clay matrix underwent the transformation of AgNPs in moving to the film surface and coalescing to larger sizes. The hierarchical change continued to form other morphologies. We observed the self-assembled morphologies including spherical (diameter ∼ 50 nm), cubic (length ∼100 nm), rod-like (length ∼ 1.6 μm and width ∼300 nm) and then to lengthy wire Ag (length ∼10μm). The kinetic mobility of AgNPs to surface and the characterization of Ag composition were confirmed through energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD).

The oscillating piezoelectric field of a surface acoustic wave (SAW) is employed to transport photoexcited electrons and holes in GaAs nanowires (NWs) transferred to a SAW beam line on a LiNbO3 crystal. We show that carriers generated in the NW by a focused light spot can be acoustically transported to a second location, where they recombine emitting short light pulses. The results presented here demonstrate the high-frequency manipulation of carriers in NWs without the use of electrical contacts, which opens new perspectives for applications in opto-electronic devices operating at GHz frequencies.

In this work, dot and anti-dot structures in Co, Ni, Ni80Fe20, Fe50Pd50, Fe73.5Cu1Nb3Si13.5B9 and Fe78B13Si9 thin films have been produced by means of nanosphere lithography. Two multi-step processes have been followed and will be here described. The first one directly exploits polystyrene nanosheres (PN) as a mask to fabricate arrays of magnetic nanoholes and dots. In the second case, the nanospheres are used to design a polymeric mask of a photoresist subsequently used to pattern a magnetic nanostructure on a film. Advantages and disadvantages of the two lithographical techniques will be here highlighted. In both processes, the dimension and mutual distance of the patterns are dependent on the starting PN diameter (in the interval 500-800 nm). Samples microstructure has been studied by means of SEM and AFM microscopy. Room-temperature hysteresis loops have been measured by an AGFM (Alternating Gradient Field Magnetometer). MFM microscopy has been exploited to study the magnetic domain pattern. All produced systems have been observed to display tunable microstructure and, consequently, various magnetic properties for application.

A novel polymer dispersant, poly(oxyethylene)-segment imide (POEM) in the structure was incorporated in the nanocrystalline TiO2 film as the electrode. The uses of the dispersants could disperse TiO2 by decreasing the van der waals force among the nanoparticles, observed by TEM. The resultant TiO2/POEM film as the photoanode rendered the dye-sensitized solar cell (DSSC) with enhanced performance. By comparing to the traditional photoanode composing of polyethylene glycol (PEG) dispersed TiO2, the POEM dispersed TiO2 provided large surface area and high roughness in the dye adsorbed film. Furthermore, the fabricated TiO2/POEM photoanode has a better light-scattering property which contributes to the improvement for the short-circuit current density (Jsc) and the power-conversion efficiency (_) of the DSSC to be 19.1 mA cm-2 and 8.7%, respectively. The performance is superior to 13.2 mA cm-2 and 7.34% for a DSSC with the photoanode containing TiO2/PEG.

We characterize “blisters”, defects observed in multilayer dielectric (MLD) coatings after exposure to acid cleaning procedures. Nanoindentation is used to make site-specific indentations across blisters to measure the mechanical response, especially their compliance under different conditions of loading. Two regions of statistically different mechanical response are identified within a blister defect and compared to the undisturbed regions of the MLD coating. The indentation response of blisters can vary across samples, and we suggest reasons for this variation.

Experiments were performed to incorporate Li and N simultaneously into the diamond lattice during hot-filament chemical vapour deposition in an attempt to produce n-type semiconducting diamond with useful electronic characteristics. Microcrystalline diamond films were grown using a mixture of methane/ammonia/hydrogen gases with tantalum as the filament. The Li was added by placing crystals of lithium nitride (Li3N) on the substrate and allowing them to melt and then slowly diffuse into the film. SIMS depth profiles showed that this process produced high levels of Li and N (0.05% - 0.5%) situated in the same region within the diamond film. The crystallinity and morphology of diamond crystals produced were confirmed using laser Raman spectrometry and scanning electron microscopy.

In this work we describe the characterization of anti-myoglobin immobilization on 3C-SiC (100) by means of surface modification with 3-aminopropyltriethoxysilane (APTES). Surface water contact angle measurements were used to compare the wettability of 3C-SiC (100) before (16 ±3°) and after APTES layer formation (61 ±1°). Atomic force microscopy (AFM) was used to confirm the homogenous formation of APTES and anti-myoglobin immobilization with EDC-sulfo NHS coupling. For the APTES surfaces no significant change in the surface roughness was obtained whereas with anti-myoglobin surfaces, particles on the order of ∼60 nm in diameter with a globular shape were observed.

Most of the research on silicon-on-insulator integrated circuits has been focused on applications for telecommunication. By using the large refractive index of silicon, compact complex photonic functions have been integrated on a silicon chip. However, the transparency of silicon up to 8.5 μm enables the use of the platform for the mid infrared wavelength region, albeit limited by the absorption in silicon oxide from 4 μm on. This could lead to a whole new set of integrated photonics circuits for sensing, given the distinct absorption bands of many molecules in this wavelength region. These long wavelength integrated photonic circuits would preferably need broadband or widely tunable sources to probe these absorption bands.

We propose the use of nonlinear optics in silicon wire waveguides to generate light in this wavelength range. Nonlinear interactions in just a few cm of silicon wire waveguides can be very efficient as a result of both the high nonlinear index of silicon and the high optical confinement obtained in these waveguides. We demonstrate the generation of a supercontinuum spanning from 1.53 μm up to 2.55 μm in a 2 cm dispersion engineered silicon nanowire waveguide by pumping the waveguide with strong picoseconds pulses at 2.12 μm [1]. Furthermore we demonstrate broadband nonlinear optical amplification in the mid infrared up to 50 dB [2] in these silicon waveguides. By using this broadband parametric gain a silicon-based synchronously pumped optical parametric oscillator (OPO) is constructed [3]. This OPO is tunable over 70 nm around a central wavelength of 2080 nm.

Finally, we also demonstrate the use of higher order dispersion terms to get phase matching between optical signals at very different optical frequencies in silicon wire waveguides. In this way we demonstrate conversion of signals at 2.44 μm to the telecommunication band with efficiencies up to +19.5 dB [4]. One particularly attractive application of such wide conversion is the possibility of converting weak signals in the mid-IR to the telecom window after which they can be detected by a high-sensitivity telecom-band optical receiver.

The silicon carbide thin film formation process, completely performed at room temperature, was developed by argon plasma and a chemical vapor deposition using monomethylsilane gas. Time-of-flight secondary ion mass spectrometry showed that siliconcarbon bonds existed in the obtained film, the surface of which could remain specular after the exposure to hydrogen chloride gas at 800 °C. The silicon dangling bonds formed at the silicon surface by the argon plasma are considered to easily accept the monomethylsilane molecules at room temperature to produce the amorphous silicon carbide film.

Recent advances in terahertz light amplification by stimulated emission of radiation in optically pumped graphene are reviewed. We present, within a picosecond time scale, fast relaxation and relatively slow recombination dynamics of photogenerated electrons and holes in an exfoliated graphene under infrared pulse excitation. We conduct time-domain spectroscopic studies using an optical pump and terahertz probe with an optical probe technique and show that graphene sheet amplifies an incoming terahertz field. The graphene emission spectral dependency on laser pumping intensity shows a threshold-like behavior, testifying to the occurrence of the negative conductivity and the population inversion. The emission spectra clearly narrow at a longer terahertz probe delay time, giving an evidence that the quasi-Fermi energy moves closer to the equilibrium at this longer terahertz probe delay time.

12Cr ODS steel samples were prepared by mechanical alloying of the metal powders with 20-30 nm Y2O3 particles followed by isostatic pressing, hot rolling and final heat treatment. Evolutions of oxide particles such as YTaO4 and YCrO3 after each fabrication step were investigated by using TEM with EDS. Crystallographic correlation between oxide particles and the matrix was investigated in a HIPped sample, and interactions between dislocations and oxide particles were observed in hot rolled or heat treated sample. Size distributions of oxide particles were measured by carbon replica samples and it was found that coarsening of oxide particles from 9 to 12 nm occurred during hot rolling process. Additional isothermal annealing at 1250 ˚C revealed that phase transformation of oxide particles from monoclinic YTaO4 to face centered cubic Y3TaO7 was observed.

Development of numerical tools for performance assessment studies of radioactive waste disposal facilities, must address the management of the wide-ranging uncertainties associated with the long-term behaviour of these complex systems. Different approaches and assumptions are made in order to identify and describe relationships between the disposal system and its environment. They take into account, among other factors, the uncertainties associated with temporal evolution of the system within a proposed scenario; the landscape changes arising from future human actions, climate and geological events and processes; the relationships between components of the disposal system and its immediate environment; the behaviour and characteristics of radionuclides within the system and their role in contributing to radiation exposure. In all cases, the different scenario-based models are typically used to determine the radiological significance of potential future discharges from waste disposal facilities. However, it is important to keep always in mind that in any specific case, the purpose of developing and/or applying a model may vary from a simple calculation (e.g. to support concept development) to detailed site-specific performance assessment in support of a disposal license application. The assumptions and modelling simplifications that are appropriate to one type of calculation may not be so easily justified in different circumstances. In order to develop the capability of modelling different long-term scenarios for a generic disposal site for low and intermediate level radioactive wastes, implementation of models of both the near-field/geosphere and biosphere were performed using general approaches for geosphere-biosphere interface, with sub-models for the whole system.

ZnO films with a nanostructure dominated by 150-200 nm size highly c-axis oriented nanorod arrays were deposited by hydrothermal synthesis over surface activated quartz substrates. Sulfur infiltration and growth of ZnO1-xSx over ZnO nanorods was carried out by chemiplating process using slow hydrolysis of thiourea solution at 95°C. Formation of ZnO1-xSx nanocrystals of 20-30 nm size over (0001) facets of the ZnO rods is shown. With progressive growth of ZnO1-xSx nanocrystal and full ZnO nanorod coverage, the formation ZnO/ZnO1-xSx core –shell nanostructure is realized. X-ray photoelectron spectroscopy analysis shows chemical shifts in O1s and S2p spectra confirming the formation of ZnO1-xSx (0.1≤x≤0.2) nanocrystal shell. Reduction in optical band gap from a 3.24 eV for ZnO nanorod core to 2.78 eV for the ZnO1-xSx shell is consistent with the band gap bowing effect due to sulfur addition over the ZnO nanorod surface.

Dedicated integrated experiments have been used to determine in situ the corrosion rate of low alloyed steels in geological repository mockups (90°C, anaerobic, 40 bars, slow synthetic water flux…). Two possible situations have been investigated: the steel can either be in direct contact with the host rock or in a solution rich in clay suspension. Electrochemical Impedance Spectroscopy (EIS), sampling gravimetry and microanalyses have been performed to determine the corrosion rate evolution with the exposure duration of the specimens. Kinetic regime modifications have been linked to structural modifications of the corrosion products interface.

Despite significant atomic-scale heterogeneity, bulk metallic glasses well below their glass transition temperature exhibit a surprisingly robust elastic regime and a sharp elastic-to-plastic transition with a yield stress that depends approximately linearly on temperature. The present work attempts to understand these features within the framework of thermally activated plasticity. The presented statistical thermal activation model, in which the number of available structural transformations scales exponentially with system size, results in two distinct temperature regimes of deformation. At temperatures close to the glass transition temperature thermally activated Newtonian plastic flow emerges, whilst at lower temperatures the deformation properties fundamentally change due to the eventual kinetic freezing of the available structural transformations. In this regime, a linear temperature dependence emerges for the stress which characterises the elastic to plastic transition. For both regimes the transition to macroscopic plastic flow corresponds to a transition from a barrier energy dominated to a barrier entropy dominated statistics. The work concludes by discussing the possible influence that kinetic freezing might have on the low temperature heterogeneous and high temperature homogeneous plasticity of bulk metallic glasses.

In this work, the synthesis of dense Pd/α–Al2O3 and Pd-Ag/α–Al2O3 ceramic composite membranes was done through the sequential electroless plating technique of Pd and Ag. The precursors are solutions of PdCl2 and AgNO3 and N2H4 salts, as reducing agent. The membranes were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The permeation tests of H2 and N2 was carried out at 20 psi of pressure and at 25°C, resulted π H2=5.2x10-9 mol H2/m2·s·Pa and π N2=8.2x10-10 mol N2/m2·s·Pa.

Cytotoxicity study of magnetic nanomaterials is a key consideration for biomedical applications. Very little is known about the cytotoxic and anti-cancer effects of nickel nanowires (Ni NWs) on mammalian cells and their interaction with proliferating cancer cells. Current therapeutics do not address the full heterogeneity of pancreatic cancers due to the resistance to apoptosis and does not suffice for a successful treatment. Therefore, synthesis of novel anticancer drugs continues to be a potential topic for pancreatic cancer research. In this study, we have investigated the cellular toxicity and anti-cancer effects of Ni NWs in one of the most aggressive human pancreatic ductal cancer (Panc-1) cell lines with the objective of development of a potential treatment strategy. Ni NWs were fabricated in a custom-made setup utilizing the electrodeposition method. Elemental analysis, crystallographic structure, and morphological properties of the synthesized Ni NWs were investigated using Energy Dispersive X-ray Analysis (EDAX), X-Ray Diffraction (X-RD) and Scanning Electron Microscopy (SEM), respectively. Panc-1 cell cultures were maintained according to a slightly modified American Type Culture Collection (ATCC) protocol. Morphological apoptogenic characteristics assessment of the Ni NWs induced Panc-1 cell was accomplished using phase contrast microscopy (PCM). Two commercially available cytotoxicity procedures including 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and trypan blue (TB) assays were utilized to determine the qualitative and quantitative cytotoxicity and anti-cancer effects of Ni NWs. As a negative control, Panc-1 cells without Ni NWs treatment were used in all experiments. Phase contrast microscopy (PCM) was used to confirm the Ni NWs internalization by Panc-1 cells. Both the MTT and TB assays, qualitatively and quantitatively confirmed the cytotoxic and anti-cancer effects of Ni NWs treated Panc-1 cells in vitro in both concentration and exposure-time dependent manners. We studied the cytotoxic and anti-cancer effects of Ni NWs on Panc-1 cells using novel integrated bionanotechnological approaches to understand the corresponding biological pathway with the objective of developing pancreatic cancer treatment. More specifically, we explored the molecular mechanisms associated with the pathway involved in Ni NWs induced toxicity against Panc-1 cells. Our results demonstrated that Ni NWs show strong candidacy for targeting cell selective applications in pancreatic cancer therapy. Key words: Nickel Nanowires, anti-cancer effects, pancreatic cancer.

Shot peening is a widely applied surface treatment in a number of manufacturing processes in several industries including automotive, mechanical and aeronautical. This surface treatment is used with the aim of increasing surface toughness and extending fatigue life. The increased performance during fatigue testing of the peened components is mainly the result of the sub-surface compressive residual stress field resulting from the plastic deformation of the surface layers of the target material, caused by the high-velocity impact of the shot. This compressive residual stress field hinders the propagation and coalescence of cracks during the second stage of fatigue testing, effectively increasing the fatigue life well beyond the expected life of a non-peened component.

This paper describes a 3D computational model of spherical projectiles impacting simultaneously upon a flat surface. The multi-impact model was developed in ABAQUS/Explicit using finite element method (FEM) and taking into account controlling parameters such as the velocity of the projectiles, their incidence angle and different impact locations in the target surface. Additionally, a parametric study of the physical properties of the target material was carried out in order to assess the effect of temperature on the residual stress field.

The simulation has been able to successfully represent a multi-impact processing scenario, showing the indentation caused by each individual shot, as well as the residual stress field for each impact and the interaction between each one of them. It has been found that there is a beneficial effect on the residual stress field magnitude when shot peening is carried out at a relatively high temperature. The results are discussed in terms of the current shot-peening practice in the local industry and the leading edge developments of new peening technologies. Finally, an improved and affordable processing route to increase the fatigue life of automotive components is suggested.