Electrochemical dissolution of ionic species into a solid is an area of great interest in several fields including nanoscale patterning and energy storage. Such dissolution is strongly influenced by several factors e.g., work function difference, dislocation density, grain size, and number of grain boundaries. These parameters are strongly influenced by mechanical deformation of the ionic conductor. Here we characterize such a system of silver (Ag) and silver sulfide (Ag2S), where incorporation of Ag into the solid ionic conductor, Ag2S, is dramatically influenced by mechanical deformation. We show more than three-fold dissolution rate enhancement when the polycrystalline conductor is compressed to one-third of its original size. We attribute this enhancement to increased dislocation density which is supported by the high current densities observed during dissolution. Additionally, reduced electronic currents suggest most of this contribution comes from increased reaction at the metal-conductor interface. Our studies have important applications in areas involving ionic transport including direct metal patterning and energy storage technology.

A synthetic hectorite nanoclay, Laponite®, with a disc shape (20 – 30 nm in diameter and 1 nm in thickness) was used as a model nanoparticle to prepare dispersions in water and different organic solvents. Although up to 20 wt% of nanoclay can be dispersed in water to form a low-viscosity stable colloidal sol, dispersions in organic solvents behave differently. The effect of the dielectric constant of the medium on the viscosity of the dispersion was studied systematically using two series of water-organic solvent miscible blends. Changes in the rheological behavior of the dispersions suggest that the dielectric constant of the organic solvent is a determining factor in the sol-gel transition of a nanoclay-containing nanofluid.

In order to clarify the phase stability of E21-type intermetallic carbides, the maximum solid solubility of carbon in Ni3AlC1-x was evaluated by taking into account the strain energy and the chemical energy for the formation of the Ni6C cluster (E M6C). It was found that the maximum carbon content calculated was 0 at.%C at E M6C≥0, 3.5 at.%C at E M6C = -5 kJ/mol, 6.5 at.%C at E M6C = -10 kJ/mol, 10 at.%C at E M6C = -15 kJ/mol and 13 at.%C at E M6C = -20 kJ/mol, respectively. Experimentally determined maximum carbon contents in Ni3Al in the literature can be explained when E M6C is ranged from -5 to -15 kJ/mol, and the solid solubility is found to be sensitive to E M6C. The attractive interaction between Ni and C seems to be due to covalent bonding. Similar attractive chemical interaction between transition metals and carbon must stabilize E21 phases.

The transient electroluminescence (EL) of phosphorescent organiclight-emitting diodes (OLEDs) was investigated. The behaviors of thetransient characteristics are analyzed using the triplet-tripletannihilation model. The device exhibited a gradual decrease in quantumcurrent efficiency owing to the triplet-triplet annihilation at a highcurrent density. At a higher current density, the reduced rise and decaytimes are due to high-density triplet excitons related to the enhancedtriplet-triplet annihilation and the increase of the nonradiative process.The modulation speed of the devices is mainly limited by the phosphorescentrecombination lifetime.

An ultrafast laser irradiation method for the removal of corrosion from Daguerreotypes without detrimentally affecting image quality has been developed. Corrosion products such as silver oxide and silver sulfide may be removed by chemical cleaning but these reactions are hard to control and are often damaging to the underlying silver, ruining the image. The Ti:Sapphire 150 fs laser pulses used in this study are focused to a beam diameter of 60 μm and are normally incident to the Daguerreotype. It was found that the corrosion layer has a lower material removal threshold than silver allowing for removal of corrosion with minimal removal of vital information contained in the silver substrate.

Direct deposition of graphene from carbon sources on foreign substrates without the use of metal catalysts is shown to be an effective process with several advantages over other growth techniques. Carbon source molecular beam epitaxy (CMBE) in particular provides an additional control parameter in carbon flux and enables growth on substrates other than SiC, including oxidized Si and sapphire. CMBE using thermally evaporated C60 and a heated graphite filament on SiC is reported here. The graphene films were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and Hall effect. Graphene films on Si-face SiC grown using the C60 source have Bernal-like stacking and n-type conduction while those grown using the graphite filament have turbostratic stacking and p-type conduction. The sheet concentration for both n- and p-type doping is linearly dependent on film thickness.

The present paper discusses the principle of dye-sensitized solar cells (DSCs) in terms of equivalent circuit model and the key issues to improve the device efficiency. Equivalent circuit model is proposed following analysis by electrochemical impedance spectroscopy of the voltage dependence of the internal resistance elements of DSCs. The influence of these elements upon cell performance in areas such as short circuit current density (Jsc ), open circuit voltage (Voc ), and fill factor (FF) was examined based on the equivalent circuit. Efficient sensitization of nanocrystalline TiO2 film was observed across the whole visible range and into the near-IR region as far as 1000 nm with a new panchromatic substituted β-diketonato Ru(II)-terpyridine dye (HIG1). Introduction of bulky alkyl substituent group in a β-diketonato Ru(II)-terpyridine dye (A3) suppress aggregate formation result in an improved performance of DSCs and the performance is independent of the additive added during the dye adsorption process. The haze factor of TiO2 electrodes is a useful index when fabricating light-confined TiO2 electrodes to improve Jsc . It was demonstrated that blocking of bare TiO2 surface with small molecules is an effective way of suppress interfacial charge recombination at the TiO2-dye/electrolyte interface and of improving shunt resistance and Voc . FF was also improved by reduction of the internal series resistance, which is composed of the following three elements: the redox reaction resistance at the platinum counter electrode, the resistance of carrier transport by ions in the electrolyte, and resistance due to the sheet resistance of the transparent conducting oxide. Finally, the highest efficiency scores of 10.4% and 11.1% (aperture illumination area 1.004cm2 and 0.219cm2, respectively) were confirmed by a public test center.

Titanate nanotube (TNT) was prepared by alkaline hydrothermal method starting from TiO2 (P25), and then CdS-TNT was prepared for visible light harvesting by immersing TNT in Cd(CH3COO)2 and then (NH2)2CS aqueous solutions subsequently and heat treated at specialtemperature. After loading with Pt, photocatalytic reduction of gas phase CO2 with water vapor was carried out under UV-VIS and visible light irradiation. The results showed that the main reaction products were CH4, C2H4, C2H6 and H2, which were online characterized by gaschromatography when the flow rate of 5000 ppm CO2 is 0.35 ml/min. The hydrogenation process also realized under visible light illumination for Pt-CdS/TNT and producted 0.44 μmol/min CH4. The maximum yield of methane reached about 130 μmol/min when Pt-CdS/TNTwas irradiated with UV-Vis light. The time profile for production yield increased steadily with time up to about 6–7 h, then a decrease of the reaction rate occurred. It is suggested that thadsorption of intermediate products CO, O2 etc. on Pt and the oxidation of Pt might be the reasons for the photocatalytic reaction deterioration.

The stability of several kinds of substrates, such as Corning #1737 glass, fused silica, synthetic silica, water free synthetic silica, zinc selenide, silicon, and diamond like carbon (DLC) coated Si in supercritical water (663K and 25MPa) were examined. Their reaction with the water was evaluated by using Fourier transform infrared (FT-IR) spectroscopy. As a result of the present experiment, it was found that DLC-coated Si is one of the most stable and useful substrates for IR spectroscopy in supercritical water.

Neutron imaging as a method to perform in situ studies of hydrogen fuel cells, hydrogen storage devices, heat pipes, and batteries has made tremendous progress in recent years. Neutrons are useful to study light elements mixed with heavy Z elements where penetration by other forms of radiation is either impossible or incapable of contrasting the light elements. Useful spatial resolution available at neutron imaging facilities is now approaching 10 micrometers. Complimentary time resolution of 30 fps or greater is also possible with a spatial resolution approaching 300 micrometers. Here we will provide an overview of the technique of neutron imaging and experimental studies with neutrons at the National Institute of Standards and Technology. Examples of in situ studies of fuel cells, hydrogen storage devices, heat pipes and batteries will be discussed.

We present the development of CMOS compatible focused ion beam (FIB)-based method for the fabrication of nanomechanical devices. With only two step process, (i) patterning by direct exposure of silicon by the gallium beam and (ii) transfer of features to the structural layer by standard microfabrication silicon etching processes, operational devices are obtained. The ion beam modified silicon, acting as the etching mask, presents an outstanding robustness for both chemical and reactive ion etching process, enabling a simplified fabrication of nanomechanical devices with sub-micron resolution. As an example, single and double clamped silicon beams have been successfully produced. The compatibility check to guarantee the integrity of the electronic performance of CMOS circuits after the energetic beam irradiation is also investigated. Patterning based on direct ion beam exposure of silicon and etching presents advantages in comparison with more conventional lithography methods, such as electron beam lithography, since it is realized without the use of any resist media, which is especially challenging for the non-flat CMOS pre-fabricated substrates.

Bacterial infection of bone (called osteomyelitis) is of great concern to the medical community. In addition to bone, numerous medical devices are susceptible to microbial colonization when implanted. These infections are chronic since bacteria form a robust adhesion to surfaces, can be protected by sticky slime matrix (called a biofilm) from the body’s immune system (which would otherwise naturally clear the bacteria), and antibiotic treatments may not resolve such infections (due to antibiotic resistance). Here, the multifunctional properties of magnetic nanoparticles (termed here superparamagnetic iron oxide nanoparticles, or SPION) will be explored for their antibacterial activity, magnetic properties, and drug deliverable properties. This study provides a first step towards the development of a new type of pharmaceutical useful for orthopedic or other device related infections by demonstrating physical (magnetic) control of antibiotics towards bacteria and biofilms.

Organized nanostructures are formed after irradiation of layers of randomly aligned single-wall carbon nanotube (SWNT)-polymer composites by a Ti:Sapphire 775 nm laser with a 150 fs pulse at fluences near 0.1 J/cm2. At varying peak fluences morphology is seen where the tubes are ejected from the substrate or formed into long, parallel structures of SWNT’s. These structures have been created on both glass substrates and carbon grids. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) investigation of the structures reveal that they are composed of bundled nanotubes typically 400 nm – 1 micron long. Large-area laser patterning of the film allows for structuring of the film without detrimental decreases in conductivity.

Solid-state neutron detectors from heterostructures that incorporate Gd intrinsically or as a dopant may significantly benefit from the high thermal neutron capture cross section of gadolinium. Semiconducting devices with Gd atoms can act as a neutron capture medium and simultaneously detect the electronic signal that characterizes the interaction. Neutron capture in natural isotopic abundance gadolinium predominantly occurs via the formation of 158mGd, which decays to the ground state through the emission of high-energy gamma rays and an internal conversion electron. Detection of the internal conversion electron and/or the subsequent Auger electron emission provides a distinct and identifiable signature that neutron capture has occurred. Ensuring that the medium responds to these emissions is imperative to maximizing the efficiency and separating out other interactions from the radiation environment. A GEANT4 model, which includes incorporation of the nuclear structure of Gd, has been constructed to simulate the expected device behavior. This model allows the energy deposited from the decay of the meta-stable state to be localized and transported, providing for analysis of various device parameters. Device fabrication has been completed for Gd doped HfO2 on n-type silicon, Gd2O3 on p-type silicon and Gd2O3 on SiC for validation of the code. A preliminary evaluation of neutron detection capabilities of these devices using a GEANT4 modeling approach is presented.

Analysis of the composition and microstructure of a Paleo-Indian micro-bead fragment from the Jones-Miller bison-kill site in Wray, Colorado, USE, and dated by radiocarbon testing to 10,200 years ago, showed that fine-motor movements were used to execute a sequence of manufacture on a singular bead. The process involved cleaving a soft, bedded oil shale, diagonally scraping a tubular surface and double-drilling a hole. The last operation caused the bead to fracture, after which it was deposited in a hearth. The raw material consists of bedded clay, silt, opal and quartz particles cemented with carbonaceous material. The presence of similar locally available oil shale with opal inclusions indicates that the raw material was acquired near the Jones-Miller site. Because of high cultural value and small size, only non-destructive analytical techniques were used to characterize the bead, including optical microscopy, UV-VIS, PIXE and XRD. Some 50-micron, previously detached particles were tested by SEM-EDS and compared to local clayey materials, both heat-treated and non-heat-treated, to show that no heat treatment sufficient to cause sintering had occurred. A resource survey in the area around the site and 50 miles to the south produced several comparative materials that were tested by the same methods given above as well as the added methods of DTA and refiring tests.

Further improvements of integrated circuits depend on the continuous downscaling of MOSFET´s, well beyond the limits for which direct tunneling currents are acceptable. These leakage currents affect both the stand-by power dissipation and the formation of the inversion layer ate the semiconductor surface, i.e., the channel formation. The most promising strategy to overcome this problem is the use of high-κ insulator in substitution of or as an additional layer on the traditional silicon dioxide. The aim of this work is using a recently developed theory to describe tunneling from inversion layers for high-κ insulators or stacks and analyze the effects of tunneling current on the thermal equilibrium in these cases.

Nanocomposites of polystyrene loaded with various amounts of anatase (ranging between 0 % wt. and 20 % wt.) have been synthesized and investigated by thermal analysis. The research was focused on the simulation of Thermogravimetric Analysis data, aiming to a refined understanding of the interactions between of polystyrene and TiO2 nanoparticles. The dependence of the first derivative of residual mass on temperature has been used to determine more accurately the temperature at which the mass loss is maxim. Several functions have been used to simulate the dependence of the first derivative of mass loss on the temperature of the sample. The highest correlation coefficient was obtained for the asymmetric Gaussian combination, which connects two halves of a Gaussian line with different linewidth. An increase of the thermal stability of the polymeric matrix upon loading with TiO2 is reported.

This paper is focused on results of a survey and study in Northern Nigeria of the inks used in Islamic manuscripts and on related information on the extant traditional technologies of ink production. Knowledge of the specific inks used in the surviving, largely undated Northern Nigerian manuscripts written in Arabic script, often referred to as Islamic manuscripts, informs us about the society that created them and embeds their production within a specific cultural context. In a place such as Africa, where the historical record and archaeological heritage are so vulnerable, we look to all vestiges of material culture in order to expand out understanding of its people, its history and their culture. These manuscripts belong to the West African tradition of Islamic culture and scholarship, of which Timbuktu was a key center. Whilst another goal of the study was to establish a watermark chronology to provide information as to the papers‘ source, when particular papers were made, when manuscripts might have been copied, and their creators‘ paper preferences, the focus of this paper is on identifying and field-testing the inks used in these manuscripts. This study of over twelve thousand folios at fourteen manuscript Northern Nigerian repositories involved 4500 km of road travel and suggested a local, interrelated tradition of dye, ink and pigment fabrication. Preliminary data led to the hypothesis that the local technology provided the basis of the indigenous manuscript production, rather than one derived from the Mediterranean and the Islamic heartlands. Finally, the diversity of these manuscripts in Arabic script reflects a culture in which not everyone was Muslim but in which Islam played a dominant role.

In order to understand the deformation and fracture behavior of Nb-Si alloys, in-situ observation was conducted during bending of small specimens at room and high temperatures. Nb-Si alloy ingots containing 18.1 at.%Si, 1.5 at.%Zr and 100 ppmMg were prepared by arc melting, followed by uni-axial solidification in an optical floating zone apparatus and a heat-treatment to obtain Nb/Nb5Si3 two-phase microstructure. Chevron-notched specimens with a dimension of 1x2x10mm were used for in-situ observation of bending tests under a confocal laser scanning microscope (CLSM) at room temperature and at 1140 °C. At room temperature the Nb-Si alloy shows a fracture toughness of 8 MPa m1/2 and the crack propagation velocity seems to be not uniform, presumably due to the ductile Nb. At 1140 °C the toughness of the alloy was about 20 MPa m1/2 and slower plastic deformation prior to the cracking was observed. The SEM observation of crack surfaces revealed that plastic deformation of Nb enhances the toughness of the alloy.