We discuss our current research focus on photovoltaic (PV) informatics, which is dedicated to functionality enhancement of solar materials through data management and data mining-aided, integrated computational materials engineering (ICME) for rapid screening and identification of multi-scale processing/structure/property/performance relationships. Our current PV informatics research ranges from transparent conducting oxides (TCO) to solar absorber materials. As a test bed, we report on examples of our current data management system for PV research and advanced data mining to improve the performance of solar cells such as CuInxGa1-xSe2 (CIGS) aiming at low-cost and high-rate processes. For the PV data management, we show recent developments of a strategy for data modeling, collection and aggregation methods, and construction of data interfaces, which enable proper archiving and data handling for data mining. For scientific data mining, the value of high-dimensional visualizations and non-linear dimensionality reduction is demonstrated to quantitatively assess how process conditions or properties are interconnected in the context of the development of Al-doped ZnO (AZO) thin films as the TCO layers for CIGS devices. Such relationships between processing and property of TCOs lead to optimal process design toward enhanced performance of CIGS cells/devices.

During irradiation in the reactor, a fraction of the fission product inventory will have segregated either to the gap between the fuel and the cladding or to the grain boundaries in the fuel. Of these nuclides, the behavior of the fission gases is best known. The part of the inventory that is rapidly released upon contact with water is designated the instant release fraction (IRF). Previous studies have shown that IRF and fission gas release (FGR) seem to be correlated. Studies of the instant release fraction from high burnup fuel is of interest for the assessment of the safety of a geological repository.

The instant release fractions of 129 I and 137 Cs from five different light water reactor (LWR) fuel rods with a burnup range of 43 to 75 MWd/kgU and a fission gas release range from 0.9 to 5.0 % were studied. Four types of fuel samples (pellet, fragment, powder and fuel rodlet) have been used in the experiments. The results show that the fuel sample preparation method has a significant impact on the release from high burnup fuel samples over the time period covered by this study. Leaching of high burnup fuel samples with fuel detached from the cladding shows the highest release. The fractional 129 I release from such fragment samples is similar to the FGR in the corresponding rod. On the other hand, corresponding fractional release of 137 Cs is lower.

In the last decades there was a growing interest in developing new light-weight intermetallic alloys, which are able to substitute the heavy superalloys at a certain temperature range. At present a new Ti-Al-Nb-Mo family, called TNM™ alloys, is being optimized to fulfill the challenging requirements. The aim of the present work was to study the microscopic mechanisms of defect mobility at high temperature in TNM alloys in order to contribute to the understanding of their influence on the mechanical properties and hence to promote the further optimization of these alloys. Mechanical spectroscopy has been used to study the internal friction and the dynamic modulus up to 1460 K of a TNM alloy under different thermal treatments. These measurements allow to follow the microstructural evolution during in-situ thermal treatments. A relaxation process has been observed at about 1050 K and was characterized as a function of temperature and frequency in order to obtain the activation parameters of the responsible mechanism. In particular, the activation enthalpy has been determined to be H= 3 eV. The results are discussed and an atomic mechanism is proposed to explain the observed relaxation process.

This work presents the successful fabrication of a thermally actuated U-shaped microgripper that has been specially designed to enable low voltage operation for bidirectional in plane deflection. The microgripper tips are carefully designed to match the biological species being manipulated, which has been demonstrated by the successful manipulation of 10 – 40 μm diameter particles used to simulate biological cells.

The development of a new high temperature structural material is recently required in various fields. As one of the potential materials, Nb-Si alloys have attracted attention due to their high melting point and low density. A microstructure composed of ductile Nb matrix containing finely dispersed spherical Nb5Si3 phase is obtained by the addition of ternary elements such as Au and it is found that such microstructure is effective in improving room temperature toughness. The main purpose of the present study is evaluating fracture toughness of Nb-Si-Au alloys using small specimens and investigating the effects of the microstructure and other minor elements on the fracture toughness. Alloy ingots of Nb-15at.%Si-3at.%Au and Nb-3at.%Au are prepared by arc-melting under Ar atmosphere, followed by heat-treatments at up to 1500oC for 100 hours. Chevron notched specimens with a size of 1.0x2.0x10mm are subjected to four-point bending tests under a laser confocal microscope for in-situ observation of crack propagation, and the effect of the microstructure and minor elements such as oxygen on the evaluated fracture toughness is investigated on both the Nb/Nb5Si3 alloys and the Nb solid solution (Nbss) alloys.

In our previous work, low resistance state (LRS) and high resistance state (HRS) areas on a nickel-oxide (NiO) film formed by applying a voltage using conductive atomic-force microscopy (C-AFM) was observed by scanning electron microscope (SEM). Comparing the observed secondary electron image (SEI) contrast to the report about the dopant-type dependence of SEI contrast reported on silicon, it was suggested that the LRS and HRS areas are, respectively, electrochemically induced p-type Ni1-xO (x > 0) and intrinsic (stoichiometric) or ntype Ni1-xO (x ≤ 0). In this paper, we verified that resistance change caused by C-AFM is due to electrochemically induced carrier injection. Reduction effect of H2 annealing on the writing area, voltage dependence of depletion layer capacitance formed between the writing area and AFM-tip using scanning nonlinear dielectric microscopy (SNDM), and the effect of Schottky barrier formation between the writing area and thin metal layer on SEI contrast were investigated. Based on these results, it was clarified that the LRS and HRS areas are, respectively, p-type Ni1-xO (x > 0) and intrinsic (stoichiometric) or n-type Ni1-xO (x ≤ 0)

A 1/6th water physical model of a 140 tons gas-stirred steel ladle is used to evaluate mixing times (τm at 95% of chemical uniformity) in a two phase system without slag (air-water) and in a more realistic three phase system (air-water-oil) to simulate the argon-steel-slag system and quantify the effect of the slag layer on the mixing time. Slag layer is kept constant at 0.004 m. Mixing times are estimated through measured changes in pH due to the addition of a tracer (NaOH 1 M). The effect of the following variables on the mixing time is evaluated for a single injector: gas flow rate (7, 17 y 37 l/min) and the injector position (R/r= 0, 1/3, ½, 2/3 and 4/5). Experimental results obtained in this work show good agreement when compared against mixing time correlations reported by Mazumdar for the two phase air-water case (no slag considered). Another comparison is done using the new concept called “effective bath height” proposed by Barati, where the mixing time is a function of the size of the slag layer since this layer dissipates part of the total amount of stirring energy introduced into the ladle by the injection of gas. Agreement is not good in this case. Finally, an estimation of the percentage of the stirring energy dissipated by the slag is computed, including other factors that govern the dissipation of stirring energy. Percentage of energy dissipated by the slag is found to be between 2.7 to 12 % depending on the process conditions.

Hydrogenation properties of some amorphous Zr-Ni-Ti-V based alloys were investigated. Pressure-composition(P-C) isotherms and hydrogen storage capacities at room temperatures were measured and effects of elemental substitution of the components with Pd or Mn were studied. The alloy electrodes were prepared by using amorphous (Zr-Ni-Ti-V)-(Pd,Mn) alloys prepared by the melt spinning method. The amorphous alloys in the electrode kept their amorphous structures during cycles of charge and discharge. The electrochemical hydrogen storage capacities were strongly affected by the substitution amounts of Pd or Mn. Even a small amount of substitution, changed the equilibrium dissociation pressures of the alloy. In the present study, the rechargeable capacity was optimized up to H/M=0.5 for the alloy electrode with the composition of (Zr45Ni30Ti25)-3at%Pd. The slope in the P-C isotherm suggested that the maximum H/M of the alloy would exceed 1.0 at higher hydrogen pressure than 1.0 MPa, however, the wide distribution of hydrogen site energy in the amorphous hydride resulted in extremely large slope in P-C isotherms, and consequently restricted the rechargeable capacities of the electrodes.

Nuclear fuels and materials present special problems to atomistic-scale modeling. At a metal-metal-oxide interface, the metal centers are charged on the oxide side, but neutral on the metallic side. The intimate contact necessitates that atomistic models for these materials be both compatible and consistent with one another at some level. A new "fragment’’ Hamiltonian (FH) model, at the atomistic level, is presented that reduces qualitatively to existing, successful models for metals, such as the embedded atom method, and ceramics, such as the charge equilibration models. Moreover, the FH model possesses both electron hopping and fundamental gaps that appear as separate terms in a generalized embedding function. The electron hopping contributions come from both one-electron and two-electron sources. These contributions appear as a result of the FH point of view, rather than being postulated. The model obeys certain wellknown theoretical limits that come from the nonlinearity of electron hopping processes as the volume of a crystal is changed. The generalized notion of embedding entails two variables instead of one. The ability to account for multiple charge states in the cations leads to the capability within the model to distinguish the qualitative differences among metallic, ionic, and covalent bonding environments. The details of all of these energies, among with fragmentfragment interactions, combine to determine the state of the atom in the material.

In a previous MRS paper, the consistency of migration parameters for strontium (Sr) in Boom Clay, obtained by different types of experiments, was examined. No consistent value could be obtained for the product ηR of the diffusion accessible porosity η and the retardation factor R. Furthermore the nearly flat concentration profile measured in one of the through diffusion experiments could not be explained by the traditional through diffusion model. A reason is that the filter plates confining the clay sample have not been taken into account.

Therefore, for Sr and tritiated water (HTO), the apparent diffusion coefficient and the product ηR in the filters are measured in through diffusion experiments on filter plates.

Taking into account the filter plates, the outlet fluxes and the Sr profiles in the clay of both Sr through diffusion experiments, are described well with (i) the previously estimated Sr apparent diffusion coefficient in the clay of 7 × 10-12 m2/s, (ii) an apparent filter diffusion coefficient in the range 2 × 10-12 m2/s to 5 × 10-11 m2/s (vs. 1 × 10-11 m2/s measured in the filter through diffusion experiments), (iii) a clay capacity factor ηR in the range between 5000 and 22000, and (iv) a filter capacity factor between 0.3 and 0.6 (in agreement with the filter through diffusion measurements). However, using the above parameters, the evolution at the inlet could not be described. So although inconsistency diminished, some inconsistency remains.

The physicochemical properties of glyme-Li[FSA] (FSA: bis(fluorosulfonyl)amide) equimolar complexes were investigated. The self-diffusion coefficients of glymes and Li+ as determined by pulsed-field gradient spin-echo nuclear magnetic resonance spectroscopy in equimolar complexes were almost identical, suggesting that all of the glyme molecules coordinated with Li+. Electrochemical characterization revealed that the oxidative stability of glyme molecules was enhanced by complexing with Li+. Using [Li(glyme)1][FSA] electrolytes and a LiFePO4cathode, a lithium secondary battery could be stably operated for more than 100 cycles at room temperature.

The use of super acids such as chlorosulfonic acid (CSA) has proven to be extremely effective at exfoliating different forms of graphite in high concentrations without covalently functionalizing the surface of the graphene. Once quenched, the acid solutions can then be vacuum filtered through acid resistant polypropylene filter paper with an average pore size of 0.2 μm to collect the exfoliated carbon into a free standing retentate film. These films can then be easily washed, removed, and redispersed into solution by sonicating the films in a surfactant solution. Films were deposited onto various substrates using a range of spin coating parameters. This study has found that exfoliated CNTs provide the best conductivity out of the four types of chemically exfoliated carbon structures studied. CNTs have also proven to be the easiest type of exfoliated carbon to disperse and are able to stay in solution with less than 1%wt surfactant. The findings have shown that the electrical conductivity of the spin coated films actually increases with RPM and is inversely proportional to the film thickness. It is possible to achieve electrical conductivities as high as 10,507 ± 3728.64 [S/m] while still maintaining the transparency of the thin films. The initial spin coating step is more efficient at low ramp rates around 100 rpm/s and results in very smooth films. High spin speeds of 1800 rpm during the casting stage are found to play a large role in improving the conductivity of the films. Lastly, drying the samples on a hot plate for 5 min. on high has significantly improved the films electrical properties and virtually eliminated the need for tedious and expensive plasma cleaning treatments.

In this paper the amount and morphology of cortical and trabecular bone porosities were estimated using optical microscopy and micro-computed tomography technique. The hierarchical structure of porosity at different structural scales spanning from a single lacuna (sub-microscale) to trabecular or cortical bone levels (mesoscale) was characterized and described. This study was conducted by using samples of untreated, deproteinized and demineralized bones, to obtain better insight into the bone structure and porosities. The motivation of this work is that the porosity in bone has a major effect on its mechanical response, yet it is often neglected in bone models. Investigations of the mechanical properties of bone and its main components (collagen and mineral phases), complemented by modeling, are of importance in orthopedics.

In order to understand the electric current distribution in a non-local geometry, the geometrical dependence of non-local Hall resistance was investigated for lateral devices consisting of an FePt perpendicular spin polarizer and a Au Hall cross. The finite element simulation was also carried out to calculate the electric potential in the devices. The experiment and the simulation indicated that non-local Hall resistance included the contribution of anomalous Hall effect (AHE) in the FePt perpendicular spin polarizer. The resistance change due to AHE in FePt became remarkable for devices with a wide electrode. Taking into account the contribution of AHE, the spin Hall angle was estimated to be 0.05 for the device with a narrow Au electrode.

Li2FeP2O7 is a newly developed polyanionic cathode material for high performance lithium ion batteries. It is considered very attractive due to its large specific capacity, good thermal and chemical stability, and environmental benignity. However, the application of Li2FeP2O7 is limited by its low ionic and electronic conductivities. To overcome the above problem, a solution-based technique was successfully developed to synthesize Li2FeP2O7 powders with very fine and uniform particle size (< 1 μm), achieving much faster kinetics. The obtained Li2FeP2O7 powders were tested in lithium ion batteries by measurements of cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge cycling. We found that the modified Li2FeP2O7 cathode could maintain a relatively high capacity even at fast discharge rates.

Most data available on the interaction of actinides with biological systems are based on physiological or biokinetic measurements, with scarce information on the structure of the actinide coordination site. This proceeding article describes an approach for structural elucidation of actinide biological complexes. Indeed most of c.a. actinide circulation pathways are unknown, as they accumulate mostly in bones, kidney and liver. In case of accidental release of radionuclide in the environment, internal contamination under either acute or chronic conditions has the potential to induce both radiological and chemical toxicity through significant interaction with the metabolome or proteome followed by possible functional modifications. For instance, the metalloproteins present primary, secondary and tertiary structures, and also different post-translational modifications, all playing a crucial role in interacting with their partners, which can be altered by actinide bonding. When tightly bound, metal ions are critical to the function, structure, and stability of the proteins, by disabling specific interactions through significant local or global conformational modifications. In order to overcome the intricacy of actinide chemistry combined with that of metalloproteins, a simplified study toward better understanding the interaction of actinides and biological systems using simple biomolecules such as amino acids has therefore been considered. Focus is made on the cation coordination site itself, given that conformational effects are not taken into account in this approach. In a first step, we have selected simple phosphorylated building blocks that may be considered as chemical representatives of some ubiquitous target metalloproteins or some important phosphorylated peptides or proteins.

We analyze the influence of the Mg concentration on several important properties of the band structure of Zn1-xMgxO alloys in wurtzite structure using ab initio calculations. For this purpose, the band structure for finite concentrations is defined in terms of the Bloch spectral density, which can be calculated within the coherent potential approximation. We investigate the concentration dependence of the band gap and the crystal-field splitting of the valence bands. The effective electron and hole masses are determined by extending the effective mass model to finite concentrations. We compare our results with experimental results and other calculations.

The effect of mechanical activation (MA) of the precursor mixture of raw materials and/or the parent glass, on the microstructure and physical and mechanical properties of iron-rich glass-ceramic materials of the system SiO2-B2O3-BaO-Fe2O3, has been studied. MA of the materials is conducted for 0, 2 or 6h using a high energy attrition milling device. Crystallization treatments are given to the parent glass at 650, 750 or 850°C for 5h. Crystallization of the samples is promoted by increased treatment temperature, and especially also by double MA at 850°C. With increasing crystallization temperature, both the density and the compressive strength increase, while porosity decreases. However, at 850°C, prolonged MA decreases both the density and the compressive strength due to an increment in porosity caused by the growth of the BaFe12O19 crystals.

Silicon nanowires (NWs) are promising thermoelectric materials as they offer large reductions in thermal conductivity over bulk Si without a significant decrease in the Seebeck coefficient or electrical conductivity. In this work, interference lithography was used to pattern a square lattice photoresist template over 2 cm x 2 cm Si substrates. The resulting vertical Si NW arrays were 1 μm tall with a packing density of ~15%, and the diameter of the Si NWs were 80 - 90 nm. The Si NW arrays were then embedded in spin-on glass (SOG) to form a dense composite material with a measured thermal conductivity of 1.45 W/m-K at 300 K. Devices were fabricated for cross-plane Seebeck coefficient measurements and the Si NW/SOG composite was found to have a Seebeck coefficient of roughly -284 μV/K, which is similar to bulk Si with the same doping. We also report a combined power generation of 29.3 μW from both the Si NW array and Si substrate with a temperature difference of 56 K and 50 μm x 50 μm device area.