bluuebunny/crossref_metadata_2025_split huggingface dataset:
ThermoChimie, the ANDRA Thermodynamic Database
Authors: Duro Lara , Grivé Mireia , Giffaut Eric 
Published: November 2012

ABSTRACTThermoChimie is the thermodynamic data base initially created by ANDRA in 1996, especially designed and qualified for systems of interest for the French high level waste repository concept. This database is supported by an experimental program on actinides and fission products and also on major components of the systems of interest, and it has been continuously updated since its creation. The validation of the database is continuously on-going through geochemical calculations related to the performance assessment of different backfill/buffer materials and/or geological formations. ThermoChimie contains data on major elements (including stability of minerals such as clays, zeolites, cementitious phases), a long list of radioelements, such as actinides and lanthanides, chemotoxic metals, as well as organic and inorganic ligands.
Migration Behaviour of Lanthanides in Compacted Bentonite with Iron Corrosion Product Using Electrochemical Method
Authors: Idemitsu Kazuya , Akiyama Daisuke , Matsuki Yoshihiko , Irie Yusuke , Inagaki Yaohiro , Arima Tatsumi 
Published: November 2012

ABSTRACTAfter the closure of a high-level waste repository, corrosion of the carbon steel overpack will occur. The corrosion products can then migrate into bentonite and affect the migration behavior of radionuclides in bentonite. Therefore, electrochemical experiments, with Fe2+ supplied by anodic corrosion of carbon steel, were carried out to study trivalent lanthanides in compacted bentonite. The interface between a carbon steel coupon and bentonite (dry density, 1.5 Mg/m3) was spiked with a tracer solution containing Nd(NO3)3, Eu(NO3)3, Dy(NO3)3, and Er(NO3)3. The carbon steel coupon was connected as the working electrode to a potentiostat and held at a constant potential between -550 and 0 mV (vs. Ag/AgCl reference electrode) for 7 days. A model using dispersion and electromigration could explain the measured profiles in the bentonite specimens. The best-fit electromigration velocity was related to the applied electric potential and was 1.0–3.8 nm/s for Nd, Eu, Dy, and Er ions. For these lanthanides, the best-fit dispersion coefficient was also related to the applied potential and was 0.8–1.6 μm2/s, and the dispersion length was calculated as 0.2 mm from the linear relationship between the dispersion coefficient and electromigration velocity. Finally, the apparent diffusion coefficient for these lanthanides was estimated as 0.6–0.9 μm2/s.
Liquid Low-level Radioactive Waste Treatment by Membrane Processes
Authors: Zakrzewska-Trznadel Grazyna , Harasimowicz Marian , Miskiewicz Agnieszka , Jaworska-Sobczak Agnieszka 
Published: November 2012

ABSTRACTThe first step in the processing of low- and medium-level liquid radioactive waste is the reduction in the volume of liquid containing small concentrations of radionuclides. Various methods for concentration of radioactive waste have been studied and developed at the Institute of Nuclear Chemistry and Technology, including membrane processes. Reverse osmosis was implemented at the Radioactive Waste Management Plant. Other methods such as ultrafiltration, membrane distillation, adsorption and different integrated processes were studied in the scope of national and international projects.This paper presents the results of research performed at Institute of Nuclear Chemistry and Technology in Warsaw concerning radioactive liquid waste treatment and the programs of implementation of these methods at nuclear centers producing such wastes, as well as the plans for the utilization of the knowledge and experience and designs of schemes for radioactive waste management in future nuclear power industry. The integrated system developed on the basis of research will be a prototype for further implementation.
Biocompatible Hybrid Plasmonic-Magnetic Nanoparticles for Bioimaging
Authors: Sotiriou G.A. , Hirt A.M. , Lozach P-Y. , Teleki A. , Krumeich F. , Pratsinis S.E. 
Published: November 2012

ABSTRACTHybrid magnetic/plasmonic nanoparticles possess properties originating from each individual material. Such properties are beneficial for biological applications including bio-imaging, targeted drug delivery, in vivo diagnosis and therapy. Limitations regarding their stability and toxicity, however, challenge their safe use. Here, the one-step flame synthesis of composite SiO2-coated Ag/Fe2O3 nanoparticles is demonstrated. The hermetic SiO2 coating does not influence the morphology, the superparamagnetic properties of the iron oxide particles and the plasmonic optical properties of the silver particles. Therefore, the hybrid SiO2-coated Ag/Fe2O3 nanoparticles exhibit desired properties for their employment in bio-applications.
Solar Spectrum Splitting Parallel Junction High Efficiency Concentrating Photovoltaics
Authors: Broderick Lirong Z. , Stefancich Marco , Roncati Dario , Albert Brian R. , Sheng Xing , Kimerling Lionel C. , Michel Jurgen 
Published: November 2012

ABSTRACTA compact, single element concentrator comprising a near linear array of prisms has been designed to simultaneously split and concentrate the solar spectrum. Laterally aligned solar cells with different bandgaps are devised to be fabricated on a common Si substrate, with each cell absorbing a different spectral band optimized for highest overall power conversion efficiency. Epitaxial Ge on Si is used as a low cost virtual substrate for III-V materials growth. Assuming no optical loss for the prism concentrator, no shadowing and perfect carrier collection for the solar cells, simulations show that 39% efficiency can be achieved for a parallel four-junction (4PJ) InGaP-GaAs-Si-Ge cell under 200X concentration, and higher efficiency is possible with more junctions.
Multi-Million Fully Atomistic Molecular Dynamics Simulations of Yarn Formation from Carbon Nanotube Forests
Authors: Machado Leonardo D. , Legoas Sergio B. , Galvão Douglas S. 
Published: November 2012

ABSTRACTIn this work we present preliminary results from multi-million fully atomistic classical molecular dynamics simulations carried out to test different existing mechanisms that have been proposed in the literature to explain the drawing of yarns from carbon nanotube forests. Despite the fact that it has been almost ten years since yarns were first drawn, there are still controversies on the mechanisms and necessary conditions that can produce yarns and sheets drawn from carbon nanotube forests. Moreover, few works have tried to understand at atomistic level the details of yarn drawing mechanisms, and no fully atomistic simulations have been carried out so far on this particular subject. Our preliminary results suggest that only direct van der Waals interactions among large bundles seem not to be enough to explain the yarn drawing process. Bundle interconnectors (such as small bundles connecting large bundles) were observed to play a critical role in our simulations. Depending on the topology of these interconnectors it was possible to observe from the simulations fibers/yarn formation from proposed structural models. These models were built based on structural information inferred from scanning electron microscopy data.
Multiscale toughness amplification in natural composites
Authors: Barthelat Francois , Rabiei Reza , Dastjerdi Ahmad Khayer 
Published: November 2012

ABSTRACTHard biological materials such as bone and nacre exhibit remarkable mechanical performance, particularly in terms of fracture toughness, despite the weakness of their constituents. Mechanical performance of nacre and bone can largely be explained through their staggered microstructure where stiff inclusions of high aspect ratio are embedded in a softer matrix. The mineral inclusions provide hardness and stiffness while the organic matrix introduces ductility. The high performance of these natural structures is unmatched by any synthetic ceramic, which therefore makes them a substantial source of inspiration for development of new artificial materials. While the modulus and strength of these structures are well understood, fracture toughness remains unclear and controversial. In this work, chevron double cantilever beam fracture tests show that the interfaces in nacre have a low toughness, comparable to that of the tablets (in J terms). This highlights the important role of structural design on fracture toughness. At the next step, a fracture model is presented to explain the toughness amplification observed in natural staggered structures based on two essential extrinsic toughening mechanisms: crack bridging and process zone. The modeling results show that toughness can be further amplified by incorporating high concentrations of small inclusions with high aspect ratio. This conclusion is applicable to construction and optimization of natural and biomimetic composites.
Hierarchical Microstructure and Elastic Properties of Leaf Petiole Tissue in Philodendron melinonii
Authors: Faisal Tanvir R. , Rey Alejandro D. , Pasini Damiano 
Published: November 2012

ABSTRACTThe leaf petiole is an organ that connects the leaf blade to the stem of a plant. From a structural viewpoint, the petiole resembles a cantilever beam that withstands torsional loading due to wind action and bending deformation due to gravity acting on the leaf blade. During growth, the petiole develops defined structural features at multiple length scales, which synergistically determine its mechanical response to external stimuli. The focus of this study is on the hierarchical level (n=3) of the cellular tissue. The goal is to capture the elastic properties of the cellular tissues of the leaf petiole in Philodendron melinonii at that hierarchy. Since the microstructure of the plant tissues resembles a non-periodic cellular pattern, we resort to a 2-D Finite Edge Centroidal Voronoi tessellation (FECVT) to generate a realistic network of polygonal cells. An analysis based on finite element analysis (FEA) is performed to explore the relation between the effective stiffness of Voronoi model and the properties of the cellular tissue. The effective (homogenized) elastic properties of the cellular tissue can be used to calculate the overall flexural and torsional stiffness of the P. melinonii petiole. The FEA of the Voronoi microstructure depicts the anisotropic stiffness properties of the P. melinonii tissue and its dependence with the graded cellularity.
Thin Film Electronic Properties of Ternary Topological Insulator
Authors: Chang Jiwon , Register Leonard F. , Banerjee Sanjay K. , Sahu Bhagawan 
Published: November 2012

ABSTRACTUsing an ab initio density functional theory (DFT), we study thin film electronic properties of topological insulators (TIs) based on ternary compounds of Tl (thallium) and Bi (bismuth). We consider TlBiX2 (X=Se, Te) and Bi2X2Y (X, Y=Se, Te) compounds. Here we discuss the nature of surface states, their locations in the Brillouin Zone (BZ) and their interactions within the bulk region. Our calculations suggest a critical film thickness to maintain the Dirac cone which is smaller than that in binary Bi-based compounds. Atomic relaxations are found to affect the Dirac cone in some of these compounds. We discuss the penetration depth of surface states into the bulk region.
Ferroelectric domain morphology, electrical and electromechanical properties of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics
Authors: Tai Cheuk W. 
Published: November 2012

ABSTRACTPb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics were fabricated by mixed-oxide route. The compositions along morphotropic phase boundary were investigated. Dielectric properties and piezoelectric coefficient were measured. The maximum relative permittivity is 33600 found in the (PIN-PT)x(PMN-PT)1-x ceramics with x = 0.1 at 167 °C. When increasing the amount of Pb(In1/2Nb1/2)O3, the piezoelectric coefficient of the ceramics decreases but the phase transition temperature increases. The selected-area electron diffraction patterns show the pseudo-cubic perovskite symmetry. Diffuse scattering is found in the diffraction pattern taken at higher order zone axis. Transmission electron microscopy study shows that the morphology of ferroelectric/ferroelastic domains is neither tetragonal nor rhombohedral configuration.
Nanostructured biofunctionalized polyurethanes for applications in regenerative medicine
Authors: Kruss Sebastian , Wolfram Tobias 
Published: November 2012

ABSTRACTPolyurethane (PU) materials are used in a wide variety of implantable devices and technologies, e.g. stents, breast augmentation, nose surgery and bladder reconstruction. Despite the excellent chemical control for manufacturing bulk materials and the good biocompatibility, a major challenge remains interfacing of PU with biological environments. A chemically controlled surface engineering approach could improve desired protein adsorption processes and cellular interactions within different tissues, preventing uncontrolled events of the implant especially in early stages shortly after surgical procedures.To gain better control over the PU surfaces we polymerized different bulk PU materials and developed a transfer-nanolithography technique to deposit inorganic Au-nanoparticles with defined structural features on the PU surface. Different nanoparticle patterns were transferred and analyzed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). Topographical features of PU substrates were investigated by atomic force microscopy (AFM). Transferred Au-nanoparticles showed high stability on PU substrates even under extreme sonication conditions. In a final step, those nanoparticles were functionalized with peptides to facilitate cellular adhesion under physiologically relevant conditions. As proof of concept, rat embryonic fibroblast cells were cultured on a peptide functionalized PU interface and investigated by SEM.In conclusion, we developed a versatile method to prepare nanostructured and biofunctionalized PUs. These PUs showed good stability characteristics and in vitro biocompatibility in cell culture assays.
Electrospun Fiber - Hydrogel Composites for Nucleus Pulposus Tissue Engineering
Authors: Strange Daniel G. T. , Tonsomboon Khaow , Oyen Michelle L. 
Published: November 2012

ABSTRACTNew materials are needed to replace degenerated intervertebral disc tissue and to provide longer-term solutions for chronic back-pain. Replacement tissue potentially could be engineered by seeding cells into a scaffold that mimics the architecture of natural tissue. Many natural tissues, including the nucleus pulposus (the central region of the intervertebral disc) consist of collagen nanofibers embedded in a gel-like matrix. Recently it was shown that electrospun micro- or nano-fiber structures of considerable thickness can be produced by collecting fibers in an ethanol bath. Here, randomly aligned polycaprolactone electrospun fiber structures up to 50 mm thick are backfilled with alginate hydrogels to form novel composite materials that mimic the fiber-reinforced structure of the nucleus pulposus. The composites are characterized using both indentation and tensile testing. The composites are mechanically robust, exhibiting substantial strain-to-failure. The method presented here provides a way to create large biomimetic scaffolds that more closely mimic the composite structure of natural tissue.
Development of new sol-gel derived Ag-doped biomaterials for dental applications
Authors: Chatzistavrou Xanthippi , Kontonasaki Eleana , Bakopoulou Athina , Theocharidou Anna , Sivropoulou Afroditi , Paraskevopoulos Konstantinos M. , Koidis Petros , Boccaccini Aldo R. , Kasuga Toshihiro 
Published: November 2012

ABSTRACTThe aim of this work was to develop a new Ag-doped bioactive material with antibacterial behavior, optimizing the properties of the new fabricated composite material in the system SiO2 58.6 -P2O5 7.2 -Al2O3 4.2 -CaO 24.9 -Na2O 2.1 -K2O 3 (wt%). Two systems with different concentrations in Ag2O (Ba with 2.1 and Bb with 4.2 wt%) were prepared by the sol-gel method and compared to the respective silver-free control composite (CONTROL). The microstructural characteristics of the developed compositions were characterized by different techniques as UV/VIS spectroscopy, X-ray diffraction analysis (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS). The antibacterial properties of the Ag-doped glass-ceramics were tested against the bacterial colony Staphylococcus aureus (S. aureus) which is very characteristic oral bacteria and the material-cell interaction was monitored in a primary culture of Human Gingival Fibroblasts (HGFs). Our study shows the successful incorporation of the silver ions in the ceramic structure and the preparation of new Ag-doped composite materials with cell-proliferation-inductive, as well as antibacterial properties indicating their potential application dental tissue restoration strategies.
Differences in Nanoscale Elasticity of Planar and Nanofibrillar Tissue Cultures
Authors: Tiryaki Volkan Mujdat , Ayres Virginia M. , Ahmed Ijaz , Shreiber David I. 
Published: November 2012

ABSTRACTAstrocytes are cellular bridges between the neurons and capillaries in the blood brain barrier. It was recently suggested that the nanophysical properties of the basement membrane of the blood brain barrier can influence astrocyte and neuron responses. In this work, cerebral cortical astrocytes were cultured on standard poly-L-Lysine coated glass substrates, Aclar substrates, and electrospun polyamide nanofibers whose properties may recapitulate those of the basement membrane. The nanoscale elasticity of each culture environment was investigated by force curve analysis and compared. The elasticity of the individual nanofibers on nanofibrillar surfaces was also investigated. Finally, variations in elasticity of scaffolds were correlated with astrocyte responses.
Effects of GaN Thin Layer on InGaN at Electrolyte-Semiconductor Interface for the Application of Photoelectrochemical Water Splitting
Authors: Fujii Katsushi , Koike Kayo , Atsumi Mika , Itoh Takashi , Goto Takenari , Yao Takafumi , Sugiyama Masakazu , Nakano Yoshiaki 
Published: November 2012

ABSTRACTPhotoelectrochemical properties of nitride semiconductors are paid attention due to their possibilities of water splitting by visible light absorption. However, the photocurrent density of InxGa1-xN, which absorbs visible light, is usually lower than that of GaN, which has larger band-gap and absorbing only UV light. The reasons of this are thought to be the band-edge position at the semiconductor-electrolyte interface and the crystal quality. The conduction band-edge decreases with increasing of indium composition and across the hydrogen generation energy at around the indium composition of 0.2. This means that the hydrogen generation ability decreases with increasing of indium composition. Low crystal quality is obtained because the lower growth temperature of InxGa1-xN than that of GaN to achieve the indium incorporation. In order to improve the photocurrent density, band-edge energy control and quantum tunneling effect are tried using the structure of thin GaN layer on InxGa1-xN here. The effect for the photocurrent densities is also discussed.
Photophysical Properties of a Nonlinear Dye in PMMA at High Concentration
Authors: Haley Joy E. , Flikkema Jonathan L. , Su Weijie , Krein Douglas M. , Cooper Thomas M. 
Published: November 2012

ABSTRACTThe effects of high concentration on the photophysical properties of a nonlinear material have been of interest for some time in our group. It is well known in the literature that for a nonlinear absorbing dye to be the most effective, high concentrations are needed. The problem is that most photophysical studies in solution are done at low concentration. These low concentration studies are important for understanding inherent materials properties but it is also important to understand what happens in a material at high concentration. In addition to this, efforts have been made to study the effects of incorporating a dye into a solid matrix environment to better understand the constraints this environment has to a given material. Preliminary results for a PMMA system reveal the formation of excimers (excited state dimers) with an increase in concentration. Excimers are forming from the triplet excited state of the E1-BTF. A rate constant for this formation is 2.3 x 106 M-1 s-1. While rather slow, at high concentration the excimer is readily formed. This must be considered when making nonlinear absorption measurements since the excimer will certainly contribute to the overall nonlinearity.
Decrease in Minority Carrier Lifetime of Crystalline Silicon Caused by Rapid Heating
Authors: Sameshima Toshiyuki , Betsuin Kochi , Yoshidomi Shinya 
Published: November 2012

ABSTRACTChange in the light-induced minority carrier effective lifetime τeff of crystalline silicon caused by rapid laser heating is reported. The top surface of n- and p-type silicon substrates with thicknesses of 520 μm coated with thermally grown SiO2 layers were heated by a 940 nm semiconductor laser for 4 ms. τeff was measured by a method of microwave absorption caused by carriers induced by 620 nm light illumination at 1.5 mW/cm2. τeff for light illumination of the top surfaces was decreased to 1.0x10-5 and 4.8x10-6 s by laser heating at 5.0x104 W/cm2 for n- and ptype 520-μm-thick silicon substrates, respectively. The decrease in τeff resulted from the generation of defect states associated with the carrier recombination velocity at the top surface region, Stop. Laser heating increased Stop to 6000 and 10000 cm/s for n- and p-type silicon samples, respectively. Heat treatment at 400oC for 4h markedly decreased Stop to 21 and 120 cm/s, respectively, for n- and p-type silicon samples heated at 5.0x104 W/cm2. Laser heating at 4.0x104 W/cm2 for 4 ms was also applied to samples treated with Ar plasma irradiation at 50 W for 60 s, which decreased τeff (top) to 2.0x10-5 s and 3.9x10-6 s for n- and p-type silicon samples, respectively. Laser heating successfully increased τeff (top) to 2.8x10-3 and 4.1x10-4 s for n- and p-type samples, respectively. Laser irradiation at 4x104 W/cm2played a role of curing recombination defect sites.
Heterogeneous Integration of a LASER Induced Fluorescence Detection Device for Point-of-Care Microfluidic Biochemical Analysis
Authors: Kamei Toshihiro 
Published: November 2012

ABSTRACTFluorescence detection is more advantageous than electrochemical detection in terms of high sensitivity, multiplexed detection capability and isolation from analyte. Integration of fluorescence detection, however, is much more difficult. First, it would require heterogeneous integration of various optical components including an excitation source, an optical filter, a lens, a mirror and a detector. Second, most of integrated fluorescence detectors, even though not fully integrated, suffer from high limit of detection (LOD) compared to conventional optical system that consists of discrete optical components. We have reduced laser light scattering in an integrated hydrogenated amorphous Si (a-Si:H) fluorescence detector, significantly improving a limit-of-detection (LOD). The detection platform comprises a microlens and the annular fluorescence detector where a thick SiO2/Ta2O5 multilayer optical interference filter is monolithically integrated on an a-Si:H pin photodiode. With a microfluidic capillary electrophoresis (CE) device mounted on the platform, the integrated system is demonstrated to separate DNA restriction fragment digests with high speed, high sensitivity and high separation efficiency, implying single molecular DNA detection when combined with polymerase chain reaction (PCR). We are now working towards integration of an excitation source to fabricate heterogeneously integrated laser-induced fluorescence detection (LIF) device that would be comprised of an InGaN laser diode, microlenses and the integrated a-Si:H fluorescence detector.