Using AFM, ellipsometric and profilometric measurements, we have investigated the topography and the thickness of the cellulose nanocristal (NCC) films prepared by two different methods: the first one is obtained by evaporation of concentrated suspension of NCC in petri-dish to produce a self-supported film; the second one is produced by dipping thin NCC layer on silicon substrate by Langmuir-Blodgett (LB) technique. Glucomanan (GM) functionalized AFM tip was brought into contact with these two kinds of NCC films in order to measure the adhesion between GM and NCC. The impact of the substrate and the thickness of NCC films on the measured adhesion forces were also studied: the mean measured adhesion force between the two polysaccharides was 17 nN regardless of the way the films were prepared. Adhesion properties can help us understand biochemical processes in the plant cell wall.

Electron-beam-induced deposition (EBID) using gas-phase precursor molecules is an extensively studied fabrication technique. Liquid-phase metal deposition has recently been shown to achieve higher purity levels than traditional gas-phase deposition [1]. The goal of this investigation was to characterize liquid-phase silver deposition for further studies in photonics. A Scanning Electron Microscope (SEM) (FEI Nova 600 NanoLab Dual Beam) was used to deposit silver on polyimide membranes from aqueous AgNO3 solution by accelerating electrons into the solution for silver ion reduction. Atomic Force Microscopy (AFM) and SEM were subsequently used to characterize the size dependence to electron dosage. We observed granular silver deposits with sub-75 nm particle size and 200-250 nm total aggregate diameters. The CASINO (monte CArlo SImulation of electroN trajectory in sOlids) program was used to model electron trajectory in the solution to relate the size to the electron spread.

Durable crystalline actinide host phases of ceramic waste forms are considered as advanced materials which are prospective for safe use of Pu and minor actinides before their final disposal. Development of self-glowing actinide-doped materials with matrices that are chemically inert and resistant to radiation damage may significantly change the approaches to actinide immobilization. Single crystals of zircon doped with different amount of Tb and 238Pu were synthesized by the flux method. Different non-radioactive crystals of Tb-doped zircon were studied first by cathodoluminescence method in order to identify the optimal content of Tb3+ that provides the highest luminescence emission. Then self-glowing crystals of zircon were grown with the optimal Tb content and small admixture of 238Pu (less than 0.1 wt. %). It was proposed that the valence state of Tb incorporated into zircon crystals can be (3+) and (4+), but only trivalent Tb is responsible for intensive luminescence. It is demonstrated that a small addition of Zr-phosphate to the flux supports Tb incorporation into zircon lattice and stabilizes preferably Tb3+. At the same time the addition of Zr-phosphate caused the crystallization of zirconia as a minor phase. Zircon crystals with very intensive self-glowing were successfully synthesized. The 238Pu content was 0.02 wt.% and the Tb concentration varied between 0.2 and 0.3 wt.%. Zirconia crystals obtained from the same experiment are characterized by weak self-glowing, although the Tb content was only 0.02 wt.%, while the content of 238Pu was comparable to that of zircon, i.e. 0.03 wt. %.

Differential scanning calorimetry, X-ray diffraction, and room temperature Mössbauer spectrum measurements of Fe73.5Cu1Nb3Si13.5B9 (Finemet) alloy have been carried out in order to study its structural and magnetic properties as a function of annealing temperature. The Mössbauer spectra of annealed Finemet alloy could be fitted with 4 or 5 sextets and one doublet at higher annealing temperatures, revealing the appearance of different crystalline phases corresponding to the different Fe sites above the crystallization temperature. The appearance of the nanocrystalline phases at different annealing temperatures was further confirmed by the recoilless fraction measurements. These made use of our recently-developed dual absorber method, which made it possible to determine precisely the recoilless fractions of the amorphous, nanocrystalline and grain boundary phases separately.

A multi-component, multiple-relaxation-time (MRT) lattice Boltzmann (LB) model has been employed to study transport processes in the nanostructured cathode catalyst layer of a prototype proton exchange membrane (PEM) fuel cell. The electrode consists of an array of ordered and aligned nanorods that are continuously coated with platinum (Pt). The effect of spacing between the nanorods was studied. Simulation results showed that smaller spacing in nanorods leads to lower utilization of the Pt catalyst due to O2 mass transport limitations. Results from the LB model were found to be in good agreement with the continuum model using the finite element method (FEM) with the same boundary conditions until the systems reached the O2 mass transport limited regions, where the solutions diverged.

We report the properties of MgO:Si film as a protective cathode material on the electrical discharge, and the electronic state of the outer-most surface on MgO:Si film characterized by helium Meta-stable De-excitation Spectroscopy (MDS) and that of several nanometer region from the surface evaluated by X-ray Photoelectron Spectroscopy (XPS). Both of the spectra are discussed focusing on the dependence upon the amount of Si in the MgO film for understanding discharge phenomena. The analyses of the experimental data imply that the discharge properties are not improved due to surface degradation with the increase of Si in MgO films. However, an in-situ discharge experiment, in which MgO:Si films are not exposed for the atmosphere after its deposition, shows that the introduction of Si up to about 1 atomic% has the potential to enhance the secondary electron emission coefficient.

In this work we present the synthesis, characterization and application of the nanodiamond- polypyrrole nanocomposite films as electrochemical active electrode for sensing cholesterol. Cholesterol oxidase and esterase have been covalently attached to the surface of the films. Results showed that the inclusion of nanodiamond to the polymeric matrix increment the surface area and provide carboxylic groups capable to perform reaction with the amide groups present in the enzymes. Further, the sensitivity of the electrode to the cholesterol content have been examined.

Stimuli-sensitive materials can change properties upon exposure to an external stimulus. Thermoreversible gelation upon heating is one example for such a stimuli sensitivity. Here, it is of significance to tailor the transition temperature and to achieve large changes of G’ and the viscosity. Grafting of the thermosensitive poly(ethylene glycol-b-propylene glycol-b-ethylene glycol)s (PEPEs) to pectin was performed in order to investigate if tailoring of the sol-gel-transition temperature can be achieved by adjusting the grafting ratio. PEPEs were aminated and grafted to the polysaccharide via EDC coupling as shown by FTIR. The sol-gel transition of the pectin, PEPE, and the grafted system (PGP) was investigated by rheology. The gelation temperature (Tgel) of the system could be adjusted by varying the grafting density of PEPE onto pectin as well as by the concentration of the thermosensitive polymer in aqueous solution. A concentration of 15 – 20 wt% of the grafted system in water led to gelation temperatures in the range of 25 – 33 °C and the critical micelle concentration (CMC) and critical micelle temperature (CMT) of the grafted systems were determined by UV spectroscopy. The viscosity and the G’ increased by four orders of magnitudes at Tgel, which is comparable to PEPEs alone, but could be reached at lower PEPE concentrations. In the future, a thorough mechanistic investigation of the gelation process would be of interest.

Two-photon polymerization (2PP) is an emerging tool in the field of additive manufacturing technologies, which allows for the elegant 3D lithographic production by means of photosensitive resins. One key advantage of 2PP is the achievable feature resolution. A few tens of nanometers are currently the resolution limit for this novel technique. Fields of applications are as diverse as photonics, microfluidics and biomedicine.

A challenging photonics application for 2PP are optical interconnects, where optical elements on printed circuit boards are connected with waveguides. The possibility for real 3D structuring allows for easier positioning of the cured structures and straightforward processing outperforming techniques such as 2D lithography or reactive ion etching in this regard. If mechanical flexibility of the printed circuit board is required as a property for certain niche applications, polysiloxanes are an interesting class of matrix material. This is also due to their low optical damping behavior and high temperature stability as the material has to withstand temperatures around 250°C during the manufacturing process. In this work, we present our latest approach to create polysiloxane-based waveguides via 2PP of specially tailored thiol-ene formulations. Latest improvements on the ease of processing and the local refractive index increase are shown as well as the proof of principle for waveguiding. Optical waveguides were successfully created via 2PP with writing speeds around 10 mm/min.

Exchange of solubilizers adsorbed on single-walled carbon nanotubes (CNTs) is probed by analysis of the peak shifts of the absorption bands of CNTs in the near-infrared region. Equilibrium constants and thermodynamic parameters of the exchange of sodium cholate for DNA (15-mers of oligo-DNAs, cytosine) on CNTs of different chirality are determined.

Thermoelectric phenomena strongly influence the behavior of chalcogenide materials in nanoelectronic devices including phase-change memory cells. This paper presents the annealing temperature and phase dependent thermoelectric properties of Ge2Sb2Te5 films including the thermoelectric power factor and the figure of merit. The Ge2Sb2Te5 films annealed at different temperatures contain varying fractions of the amorphous and crystalline phases which strongly influence the thermoelectric properties. The thermoelectric power factor increases fom 3.2 μW/mK2 to 65 μW/mK2as the crystal phase changes from face-centered cubic to hexagonal close-packed. The data are consistent with modeling based on effective medium theory and suggest that careful consideration of phase purity is needed to improve the figures of merit for phase change memories and potentially for thermoelectric energy conversion applications.

This investigation deals with the effect of 2/0, 1/1 and 1/0.5 Cr/Mo ratios on the local fraction, distribution and the comparative size of carbides precipitated in cast nodular iron. “Y” block castings with a thickness of 1.5 cm are cast in green sand molds. Two samples are cut from each casting, one located on the center and another on the wall. The carbide volume fraction is evaluated by a digital analysis system. Each sample is analyzed in three zones: bottom, middle and top. Carbide mappings are generated according to the average local carbide fraction in order to get the distribution of carbides on the casting. Results show that higher volume fractions of carbides precipitate for the ratio 2/0 of Cr/Mo with values between 28.5 and 19.5%. The lowest fraction of carbides is presented in nodular iron alloyed with a Cr/Mo ratio of 1/1 between 6.5 and 4.6%. Also a very heterogeneous distribution of the carbides is observed in the three alloys and massive carbides are observed in the last freezing zone of the castings.

Arabinoxylans are polysaccharides constituted of a linear backbone of xylose in which arabinose substituents are attached, some ferulic acid esterifies arabinose. Arabinoxylan can form covalent gels by oxidative coupling of ferulic acid. Arabinoxylan gels could have potential applications for colon-specific biomolecules delivery due to their macroporous structure, and their aqueous environment and their dietary fiber nature. Lycopene has received increasing attention for its possible role in the prevention of colon cancer. It has been previously reported that arabinoxylan gels could be formed in presence of lycopene with no detriment on the lycopene antioxidant activity. The objective of this research was to investigate the in vitro degradation of arabinoxylan gels (AX gels) by two human colon bacterial species (Bacteroides ovatus and Bifidobacterium longum). Bacterial counts (CFU ml-1) and metabolic heat production (p) followed a similar pattern with a high response during the first 24 h at 37 °C. A regression model related CFU ml-1 and p (r2= 0.98). These results show that AX gels could be carriers for lycopene delivery in colon due structure degradation by gut microbiota.

Lanthana-supported Ni and Co catalysts were investigated by “operando” techniques (XAS and APPES) for methane reforming reactions. The samples were prepared by the “solid phase crystallization” method (spc), where the precursors La(Ni1-xCox)O3 contains homogeneously distributed metals (Ni, Co) in the crystal structure (perovskite), which, on further reduction, result in the formation of catalytic system Ni1-xCox/La2O3. The monometallic samples (NiLaO3, CoLaO3) have been compared with a bimetallic system of an intermediate composition Ni0.5Co0.5LaO3. This “operando” study has allowed us to obtain important conclusions about the bimetallic particles and the metal-support interactions. The data revealed the formation of bimetallic particles (NiCo); on these ones, the Ni avoids the Co oxidation during the reaction. However, this protection does not induce an improvement in the activity, which presents an intermediate behaviour between Ni/La2O3 and Co/La2O3. These bimetallic particles form a pseudo-alloy with the surface enriched in cobalt (under reduced conditions), resulting nearly in a core-shell structure (Ni@Co).

We proposed and computationally analyzed a nonvolatile power-gating field programmable gate array (NVPG-FPGA) based on pseudo-spin-transistor architecture with spin-transfer-torque magnetic tunnel junctions (STT-MTJs). The circuit employs nonvolatile static random memory (NV-SRAM) cells and nonvolatile flip-flops (NV-FFs) as the storage circuits. The circuit configuration and microarchitecture are compatible with SRAM-based FPGAs, and the additional nonvolatile memory functionality makes it possible to execute efficient power-gating (PG). Break-even time (BET) for the nonvolatile configuration logic block (NV-CLB) of the NVPG-FPGA was also analyzed, and reduction techniques of the BET were proposed, which allows highly efficient PG operations with a fine granularity.

In this study, a novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of copper-based nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows for the placement of a liquid precursor containing the catalyst into the final reactor geometry without the need of impregnating or coating of a substrate with the catalytic material. The so generated foam-like porous ceramic shows properties highly appropriate for use as catalytic reactor material, e.g., reasonable pressure drop due to its porosity, high thermal and catalytic stability, and excellent catalytic behavior.

The catalytic activity of micro-reactors containing this foam-like ceramic is tested in terms of their ability to convert alcoholic biofuel (e.g. methanol) to a hydrogen-rich gas mixture with low concentrations of carbon monoxide (up to 75% hydrogen content and less than 0.2% CO, for the case of methanol). This gas mixture is subsequently used in a low-temperature fuel cell, converting the hydrogen directly to electricity. A low concentration of CO is crucial to avoid poisoning of the fuel cell catalyst. Since conventional Polymer Electrolyte Membrane (PEM) fuel cells require CO concentrations far below 100 ppm and since most methods to reduce the mole fraction of CO (such as Preferential Oxidation or PROX) have CO conversions of up to 99%, the alcohol fuel reformer has to achieve initial CO mole fractions significantly below 1%. The catalyst and the porous ceramic reactor of the present study can successfully fulfill this requirement.

The results of the present study confirm that product gas mixtures with up to 75% hydrogen content and less than 0.2% CO content can be achieved, which is an excellent result. The reactor temperature can be kept as low as 220°C while obtaining a methanol conversion of up to 70%. The used PROX catalyst showed selective CO conversion rates above 99.5% for temperatures between 80 and 100°C in presence of large molar fractions of H2O and CO2.

This work studies the synthesis of styrene copolymers obtained from the reaction between isophthalic unsaturated polyester resins and styrene with the aim of improving the mechanical properties of sheet moulding compounds (SMC), specifically their flexibility and impact resistance.

The experimental work involves the experimental design; the SMC synthesis with different concentrations of 4 additives (methylmethacrylate; diethylenglycol, dioctilphthalate, and a commercial flexible resin); and the mechanical characterization including measurements of load-deflection curves; flexural strength (FS), flexural modulus (FM) and impact resistance (IR).

The use of three-way catalysts is an accepted method to minimize NOx and CO emissions generated by internal combustion engines. These catalysts are generally formed by the support, stabilizers, promoters metal and transition metals, the most used metals of the platinum group. The use of cerium as a promoter is usually related to its ability to store oxygen and structural aspects such as the property of increasing the dispersion of metals and slow change of phase of the stabilizing support. On the other hand, the metal copper was explored as a possible replacement for palladium and platinum in the reduction of NO by CO. In this work, fibers of cerium oxide doped with copper were obtained from an acetate solution of cerium and coppers nitrates and polyvinyl butyral (PVB). This solution went through the process of electrospinning to produce nanostructured fibers. After heat treatment, cerium oxide fibers were obtained. These fibers were characterized structurally by scanning electron microscopy (SEM), had their specific surface area determined by BET method, were subjected to thermogravimetric test to determine their thermal decomposition and were analyzed by X-ray diffraction. The catalytic activity was assessed by the amount of O2 consumed and CO and CO2 formed for the combustion of methane and air. SEM images show fibers oriented randomly in the substrate. TEM images show that the diameter of the fibers is approximately 100 nm and the size of its crystallites are around 20 nm. In the presence of the catalyst, the combustion reaction started around 500°C, with the consumption of methane and oxygen and the formation of CO and/or CO2. There was no emission of NO and NOx gases during the tests with catalysts.

Nickel base alloys are considered among candidate materials for engineered barriers of nuclear repositories. The localized corrosion resistance is a determining factor in the materials selection for this application. This work compares the crevice corrosion resistance of selected nickel base alloys, namely 625, G-30, G-35, C-22, C-22HS and HYBRID-BC1. The crevice corrosion repassivation potential (ER,CREV) of the tested alloys was determined by the Potentiodynamic-Galvanostatic-Potentiodynamic (PD-GS-PD) method. The testing temperature was 60ºC and the chloride concentrations used were 0.1 M, 1 M and 10 M.

A linear relationship between ER,CREV and the logarithm of chloride concentration was found. ER,CREV increased linearly with PREN (Pitting Resistance Equivalent Number) in concentrated chloride solutions. ER,CREV is the sum of three contributions: ECORR*, η and ΔΦ. ECORR* and η increased linearly with PREN, while ΔΦ increased linearly with PREN for concentrated chloride solutions, not showing a definite trend with PREN for the less concentrated solutions.

Resonators and switches are fabricated on LSI for advance wireless communication systems. In addition to surface micromachining, adhesive bonding has been applied for the fabrication. Lamb wave resonators are fabricated for multi-frequency oscillators by surface micromachining. Multi-band filters are formed by a MEMS process after bonding a Si wafer to a LSI wafer (wafer bonding first approach). SAW filters are made by bonding a MEMS wafer to a LSI wafer (wafer bonding last approach). Variable capacitors are fabricated on a piezoelectric LiNbO3 wafer. Wafer level packaging techniques are developed to encapsulate the MEMS on LSI. Open collaboration as shared wafer, prototyping facility and hands-on access fabrication facility are discussed to reduce a cost and a risk in the development of the MEMS on LSI.