We have examined the compression response of a ternary Fe2Nb Laves phase by deforming micropillars with a diameter of ~2 μm produced by focused ion beam milling from a two-phase Fe-15Nb-40Ni (at.%) ternary alloy consisting of the Laves phase and γ-Fe. The Laves phase micropillars exhibit high strength of about 6 GPa (of the order of the theoretical shear strength of the material), followed by a burst of plastic strain and shear failure on the basal plane. If dislocation sources are introduced on a non-basal plane in the micropillars by nanoindentation prior to compression, yielding occurs at a significantly lower stress level of about 3 GPa and plastic deformation by slip proceeds on a pyramidal plane close to (-1-122). Furthermore, if regenerative dislocation sources for basal slip are present in the micropillar, the Laves phase can be continuously plastically deformed in a stable manner to at least 5% strain at a significantly lower stress of 800 MPa. We thus demonstrate the plastic deformation of this ternary Laves phase at the micron-scale at room temperature when sufficient dislocation sources are present.

Recently much interest has been directed toward solution processable polymeric semi-conductor materials containing thiophene based moieties.[1] In particular, dialkylated tetrathienoacene (fused thiophene) copolymers have been used as high mobility semiconductors in field-effect transistors with a field-effect hole mobility exceeding 0.3 cm2/Vs.[2] Expansion of this class of materials to include new materials with either linear (DCnFT4) or branched (DbCnFT4) di-alkyl-substituted fused thiophenes has been achieved with the development of two distinct synthetic routes for ring formation and the introduction of the side-chains.

DC17FT4 was prepared from tetrabromothieno[3,2-b]thiophene through a sequence of diketone formation, cyclization, hydrolysis and decarboxylation. Synthesis of the new compound di-2,4,4-trimethylpentyl-FT4 (DbC8FT4) has been accomplished in a more complex 8 step process, featuring a mono-ketone-ester as a key intermediate.

DCnFT4 can be brominated in the 2- and 6-positions with NBS. The dibromide can then be used to form copolymers through cross coupling reactions. These polymers are solution processable semi-conductors. The polymers have been characterized by GPC and within organic thin-film transistor (OTFT) devices.

Surface adsorption represents a competition between collision and scattering processes that depend on surface energy, surface structure and temperature. The surface reactivity of the actinides can add additional complexity due to radiological dissociation of the gas and electronic structure. Here we elucidate the chemical bonding of gas molecules adsorbed on Pu metal and oxide surfaces. Atmospheric gas reactions were studied at 190 and 300 K using x-ray photoelectron spectroscopy. Evolution of the Pu 4f and O 1s core-level states were studied as a function of gas dose rates to generate a set of Langmuir isotherms. Results show that the initial gas dose forms Pu2O3 on the Pu metal surface followed by the formation of PuO2 resulting in a layered oxide structure. This work represents the first steps in determining the activation energy for adsorption of various atmospheric gases on Pu.

In this work, the thermal conductivity of composites made up of carbon nanotubes embedded in a polyester resin is investigated by comparing experimental data with theoretical predictions. The composite samples were prepared with a random and aligned distribution of carbon nanotubes. Its thermal conductivity is then measured by using the photothermal radiometry technique. The obtained experimental data is accurately described by the proposed theoretical model, which takes into account the size effects of the nanotubes. It is expected that the obtained results can provide useful insights on the thermal design of composites based on carbon nanotubes.

Water-splitting to form hydrogen was examined by using strontium titanate (SrTiO3) nanofibers as photocatalysts. SrTiO3 nanofibers were fabricated by hydrothermal treatment of amorphous titanium dioxide nanofibers, which were electrospun from the mixture of polyvinylpyrrolidone (PVP), titanium(IV) butoxide, and acetylacetone. The hydrothermal treatment involved the reaction of amorphous TiO2 nanofiber template with strontium hydroxide octahydrate (Sr(OH)2·8H2O) for 20 hours at 120 ºC. The product was calcined to form crystalline SrTiO3 nanofibers, which were characterized via Scanning Electron Microscopy (SEM)/Energy Dispersive Spectroscopy (EDS) and tested their photocatalytic activities for the water splitting. The hydrogen production with the fabricated SrTiO3 nanofibers was found to be 6.1 μmol·h-1·g-1 catalyst, which is twice that of commercially available SrTiO3 nanoparticles (3.0 μmol·h-1·g-1 catalyst).

Enzyme-Linked Immuno-Sorbent Assay (ELISA), and other methods based on the same principle, are sensitive and specific, but they suffer from several disadvantages, such as their inherent complexity and requirement for multiple reagents, incubation and washing steps and require a relatively large sample size. We have adapted a new carbon nanotube field effect transistors (CNT-FET) based platform to capture Escherichia coli antigens using only the capture anti-body showing good correlation with an established ELISA assay contrived positive and negative specimens were used to test the new CNT-FET platform and results were obtained within three minutes per each sample. The test is easy to perform, rapid, and cost efficient making it a valuable screening tool for E. coli. In this study, we looked at the applicability of using CNT field effect transistor based biosensor as a rapid diagnostic platform for Escherichia coli O157:H7. The CNT-FETs platform detected positive E. coli samples in three minutes using only 2.5 μL of sample volume. This low sample volume required by the CNT-FET platform can be especially advantageous for diagnostic tests constricted by limited amount of samples.

Polycrystalline solutions of 0.6(Bi0.9La0.1)FeO3-0.4Pb(Ti1-xMnx)O3(BLF-PTM, x=0 and 0.01)have been fabricated by the so-gel process combined with a solid state reaction method. BLF-PTM exhibits the nonlinear dielectric and piezoelectric responses under applied fields. Rayleigh law has been used to evaluate the irreversible contribution of the domain walls movement to the nonlinear dielectric response. Rayleigh analysis reveals that a mechanism with no associated loss exists in the BLF-PTM of x=0.01. The real part piezoelectric coefficient of BLF-PTM linearly increases with increasing the electric fields. The dielectric and piezoelectric nonlinear coefficient of 0.17×10-3 m/V and 0.897 ×10-17 m2/V2 respectively are obtained for BLF-PTM of x=0.01,which are smaller than those of 0.22×10-3 m/V and 1.19 ×10-17 m2/V2 for BLF-PTM of x=0. Our results indicate that Mn doping increase the intrinsic piezoelectric properties of BLF-PTM reducing the extrinsic contributions to piezoelectric responses.

It is well known that tungsten tri-oxide (WO3) exhibits electrochromic and gasochromic properties. When Pt-nanoparticle-dispersed tungsten oxide (Pt-WO3) is exposed to hydrogen gas, the optical and electrical properties of the Pt-WO3 change drastically. Consequently, it is expected that thin films of WO3 can be applied as hydrogen gas leakage sensors. In this study, thin films of Pt-WO3 were prepared on glass substrates using a sol-gel process. The optical and electrical properties of the films were evaluated. Amorphous and crystalline WO3 were easily obtained by changing the heat-treatment temperature. The ion diffusion coefficient of the film depended on the WO3 structure (i.e., whether it was amorphous or crystalline) because the density of amorphous WO3 is lower than that of crystalline WO3. Films with low crystallinity were found to have superior chromic properties to both those with high crystallinity and amorphous films. Thin films of Pt-WO3 prepared at 673K showed the largest change in optical transmittance and electrical conductivity when exposed to H2 gas compared with thin films prepared at other temperatures. When this film was exposed to 100% H2 gas, the normalized transmittance decreased rapidly (in less than 0.2 sec) from 100% to almost 50%. The optical absorbance of the film was dependent on the H2 gas concentration (mixed with N2 gas) in the range from 0.1 to 5% and the relationship between them was linear. The relationship between the electrical conductivity and hydrogen gas concentration (mixed with N2 gas) in the range from 100 to 10000ppm was also linear.

To enhance a global critical current in a superconductor, it is indispensable to understand current limiting factors and their influence on such a critical current. From this point of view, we have investigated in-plane distribution of local critical current density and its electric field criterion in a thin-film superconductor by using scanning-Hall probe microscopy. In a remanent state, after the application of sufficiently high magnetic field to a sample, current flows at critical current density according to the critical state model. Such distribution of current density was estimated from that of measured magnetic field using the Biot-Savart law. Furthermore, the corresponding electric field criterion was evaluated from the relaxation of such remanent magnetic field by considering Faraday’s law. This means that we could estimate in-plane distribution of local critical current density as a function of electric field criterion in a nondestructive manner. This characterization method would be very helpful for finding current limiting factors in a thin-film superconductor and their influence on its global current density versus electric field properties which would usually be obtained by four-probe method.

This research includes results on the corrosion performance of reinforcing steel in cement-based mortar (pH ~ 13) when cactus (Opuntia Ficus Indica –Nopal) slime was used as an addition. The cactus slime addition was mixed at different concentrations by mixing water mass (0%, 1.5%, 4%, 8%, 42%, and 95%). Half-cell potentials and LPR measurements were performed at different time periods to characterize the possible corrosion inhibiting effect of the cactus additions tested. Results showed good corrosion inhibiting effect of Nopal slime on reinforcing steel, in all tested solutions, when chloride ions were present. The addition of such cactus led to an apparent formation of a denser and more packed oxide/hydroxide surface layer on the steel surface that decreased corrosion activity. This oxide/hydroxide layer growth was confirmed from microscopic evaluation of the metal surface layer performed at the end of the research program. The preliminary findings suggest that adding Nopal slime in concentrations between 4% and 8%, by water mass, might be suitable for durability enhancing applications in cement-based mortar.

We proposed the use of Copper (Cu) and Zinc (Zn) nanoparticles as the electrodes for thin-film microbatteries in the applications of micro-scale sensors. Compared to the widely used lithium-based batteries, Cu and Zn nanoparticles are less expensive, less prone to oxidation (thus involving simpler fabrication steps) and flammability, safe to use, and only requires very simple fabrication processes.Even though the voltage output is inherently smaller (∼1V) than conventional lithium-based batteries, it is sufficient for low-voltage Integrated Circuits (IC) technologies such as 130 nm and 90 nm channel length transistor processes.

Commercial paper will be used as the separator to demonstrate the battery capacity. Paper that acts as the separator is slurry-casted with nanoparticles (30-40 nm in size) on both sides. The thickness of the metal nanoparticles-coated thin films and the paper separator are 1 μm and 100 μm, respectively.

The electrodes were developed to achieve high conductivity (lower than 1 (Ω·cm)-1) with smooth surface, good adhesion, and flexibility. The metal nanoparticles will be formulated to slurry solutions for screen printing or ink-jet printing for the battery fabrication. For fabrication purposes, the slurries viscosity is approximately in the range of 10-12 cPs at the operating temperature, a surface tension between 28-33 dynes/cm. During the fabrication process including printing/coating and sintering, reductive environment is required to minimize the oxidation. AFM (Atomic Force Microscopy) and EDS (Energy Dispersive Spectroscopy) results will be employed to demonstrate the surface morphology as well as the percentages of metal oxides. Batteries will be tested with and without an ionic liquid for comparison. Humidity effects on the battery performance will also be discussed.

Different geometries that are designed to make the batteries with higher voltage or charge will be proposed. Characterization results will include the open-circuit voltage, dielectric property, charging and discharging curve, capacitance and capacity, AFM of the surface test, EDS of the electrodes and the SEM (Scanning Electron microscopy) of the particles.Ourresearch suggest that conductive paper can be scalable and could make high-performance energy storage and conversion devices at low cost and would bring new opportunities for advanced applications.

Temperature dependence of the lattice parameter and elastic moduli in Fe-40 and -43Al (at.%) was investigated by high temperature X-ray diffractometry (XRD) and the Electro-Magnetic Acoustic Resonance (EMAR) method. The thermal vacancy concentration was estimated from the activation enthalpy and entropy data of vacancy formation previously reported for FeAl. It was found that both the lattice parameter and the elastic moduli of FeAl have a linear relationship with temperature even in the temperature range where thermal vacancy concentration rapidly increases (above 400 °C), thus suggesting that newly generated thermal vacancies at elevated temperature do not make significant influence on the lattice parameter and the elastic properties of B2-type FeAl.

In biological hydrogels, the gel matrix is usually reinforced with micro- or nano-fibers and the resulting composite is tough and strong. In contrast, synthetic hydrogels are weak and brittle, although they are highly elastic. Other than in food, the main structural application of hydrogels is as soft contact lenses. The developing interest in soft tissue engineering has exposed a need for strong synthetic hydrogels to act as scaffolds for tissue growth.

In this work a new class of hydrogels based on fiber reinforced hydrogel composites with a cartilage-like structure is designed. A 3D rapid prototyping technique was used to form crossed “logpiles” of elastic fibers that are then impregnated with an epoxy-based hydrogel in order to form a fiber-reinforced gel structure. The fibrous construct improves the strength, modulus and toughness of the hydrogel and also constrains the swelling. By altering the construct geometry and studying the effect on mechanical properties we will develop the understanding needed to design strong hydrogels for biomedical devices and soft machines.

The electronic response of actinide systems under high-pressure conditions is undoubtedly of broad scientific interest but simultaneously very difficult to qualify. We will focus here on the use of inelastic x-ray scattering and its significance for actinides research through recent examples. IXS indeed combines several advantages that turn it into a powerful probe of the electronic and valence properties of f-electron systems. Besides element and orbital selectivity, resonant IXS can overcome core-hole lifetime broadening thus providing sharper spectral features and finer details about the electronic structure. Second, non-dipolar transitions are allowed in non-resonant IXS at high momentum transfer; thus “giant dipolar” Fano-like resonances that overwhelms the electron response at the O4,5 edges can be avoided. Recent results of IXS under pressure in Am and U under pressure are presented along with perspectives for actinides research at SOLEIL synchrotron.

Calcium and barium zirconium phosphates were prepared by hot isostatic pressing and their thermophysical properties investigated for potential use as actinide hosts for inert matrix fuels (IMF) in light water reactors. The materials are thermally stable up to at least 1600°C in air, however they degrade above around 1400°C in an inert atmosphere. The heat capacity and thermal conductivity were measured from room temperature up to 1200°C. The thermal conductivity coefficient for both CZP and BZP at 1000°C is 1.0 W m-1 K-1, a relatively low thermal conductivity that requires NZP-type materials to be dispersed in a composite cercer or cermet IMF.

In this paper we examine the mechanical properties of individual lamellae from bone material using novel atomic force microscopy (AFM)-scanning electron microscopy (SEM) techniques. Individual lamellar beams were selected from bone using focussed ion beam (FIB) microscopy and mechanically deformed with the AFM while observing failure modes using SEM. Both the elastic and fracture behavior of the bone lamellae were determined using these techniques.

The concept of THz detection based on excitation of plasma waves in two-dimensional electron gas in Si FETs is one of the most attractive ones, as it makes possible the development of the large-scale integrated devices based on a conventional microelectronic technology including on-chip antennas and readout devices integration. In this work we report on investigations of Terahertz detectors based on low-cost silicon technology field effect transistors. We show that detectors, consisting of a coupling antenna and a n-MOS field effect transistor as rectifying element, are efficient for THz detection and imaging. We demonstrate that in the atmospheric window around 300 GHz, these detectors can achieve a record noise equivalent power below 10 pW/Hz0.5 and a responsivity above 90 kV/W once integrated with on-chip amplifier. We show also that they can be used in a very wide frequency range: from ∼0.2 THz up to 1.1 THz. THz detection by Si FETs pave the way towards high sensitivity silicon technology based focal plane arrays for THz imaging.

Multiphase Mo-Si-B alloys are potential candidates for applications in the aerospace and power generation industry due to their enhanced creep and oxidation resistance at ultra-high temperatures. It is documented that the microstructure and the resulting properties of Mo-based alloys are heavily influenced by their fabrication procedure. In this study we investigate different multiphase Mo-Si-B alloys processed by zone melting (ZM) starting from cold pressed elemental powders. Microstructural characterization of zone melted alloys based on SEM investigations shows elongated arrangements of phases parallel to the growing direction as well as homogeneously distributed phases in the cross-section for some of the alloys investigated. First compression creep tests were performed at about 1100°C. In comparison to the creep resistance of powder metallurgically (PM) processed alloys the behaviour of ZM materials was found to be substantially improved. Hence, targeted application temperatures of around 1200°C to 1300°C may become feasible. Furthermore, the oxidation behaviour was found to be influenced by the volume fraction of the Mo solid solution phase since the volatilization of the Mo solid solution phase leads to a mass loss of the compound.

In this work, we report on the use ion of implantation to synthesize resistive memory oxides. The surface of copper thin films was converted to copper oxide using oxygen implantation. Devices fabricated from the copper oxide (CuxO) layers exhibited unipolar switching behavior without the need for a forming voltage. Technology scaling was demonstrated by oxygen implanting copper damascene vias. Unipolar switching was observed in via-based devices down to 48 nm. The current-voltage data of devices scaled from 100 μm to 48 nm suggests that the RESET transition is related to localized Joule heating. Tantalum oxide (TaxOy) was also created by oxygen implantation but exhibited bipolar resistive switching. Analysis of the conduction suggests that the difference between the two resistance states in these devices is largely due to a lowering of the Pt-TaxOy Schottky barrier.

Electrospinning is a versatile technique for fabricating three-dimensional(3D) nanofibrous scaffolds and the scaffolds have been found to elicitdesirable cellular behavior for tissue regeneration because the nanofibrousstructures mimic the nanofibrous extracellular matrix (ECM) of biologicaltissues. From the material point of view, the ECM of bone is a nanofibrousnanocomposite consisting of an organic matrix (mainly collagen) andinorganic bone apatite nanoparticles. Therefore, for bone tissue engineeringscaffolds, it is natural to construct nanofibrous nanocomposites having abiodegradable polymer matrix and nanosized bioactive bioceramics. Ourprevious studies demonstrated: (1) electrospun nanocomposite fiber loadedwith calcium phosphate (Ca-P) were osteoconductive and could promoteosteoblastic cell proliferation and differentiation better than pure polymerfibers; (2) The controlled release of recombinant human bone morphogeneticprotein (rhBMP-2) from scaffolds provided the scaffolds with desiredosteoinductivity. In the current investigation, novel bicomponent scaffoldsfor bone tissue engineering were produced using our established dual-sourcedual-power electrospinning technique to achieve both osteoconductivity andosteoinductivity. In the bicomponent scaffolds, one fibrous component waselectrospun Ca-P/PLGA nanocomposite fibers and the other component wasemulsion electrospun PDLLA nanofibers incorporated with rhBMP-2. Throughelectrospinning optimization, both fibers were evenly distributed inbicomponent scaffolds. The mass ratio of rhBMP-2/PDLLA fibers to Ca-P/PLGAfibers in bicomponent scaffolds could be controlled using multiple syringes.The structure and morphology of mono- and bicomponent scaffolds wereexamined. The in vitro release of rhBMP-2 from mono- andbicomponent scaffolds showed different release amount but similar releaseprofile, exhibiting an initial burst release. Blending PDLLA withpolyethylene glycol (PEG) could reduce the initial burst release ofrhBMP-2.