bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Source Release Model with Application to the LANL LLRW Disposal Site Performance Assessment
Authors: Vold E. L. 
Published: April 2011

AbstractA source release model was developed to quantify time dependent liquid phase releases of radioactive material to the vadose zone from a disposal site. The model has been implemented to evaluate the source terms in the Performance Assessment for the Los Alamos National Laboratory (LANL) Low Level Radioactive Waste (LLRW) Disposal Facility at Area G, an analysis of the long term post-closure impact of disposal operations required by the USDOE orders.Analytic solutions describe transport through the model compartments: the solid phase waste package, the liquid phase within each waste package and the liquid phase within the disposal unit. The model accounts for elemental solubility limits and retardation coefficients (R) separately in the waste package and in the disposal unit. Several parameters define the site specific aspects of the disposal unit. In our case for example, the disposal unit is waste buried with crushed volcanic tuff, and a small net infiltration rate is determined from independent numerical studies. The analytic solution allows efficient explorations of the sensitivity to the input parameters. Numerical solutions extend the model to account for decay product ingrowth which may have different transport properties than the parent nuclides.Results quantify the decrease of source release rates with package or disposal unit Kd, and the effects of solubility limits. At the LANL LLRW disposal site, thorium and uranium are the only significant contributors -to dose which are solubility limited. Otherwise, a ‘rapid rinse’ waste package category dominates the peak disposal unit efflux. This occurs for the LANL disposal site at about 100 years for nuclides with Kd= 0 (R= 1) and for proportionately longer times as Kd or R increases. Additional simple analytic models or detailed numerical codes can be coupled to these results to predict groundwater concentrations.
Effects of Aging on the Solubility of Palladium
Authors: Oda C. , Yoshikawa H. , Yui M. 
Published: April 2011

AbstractPalladium solubility was measured in a dilute aqueous solution at room temperature in the pH range from 3 to 13 under anaerobic conditions. Crystalline Pd metal was clearly visible and the concentration of palladium in solution decreased gradually with aging time. The palladium concentrations in solution were less than 9.4×10-10M in the pH range from 4 to 10 and increased to 10-7M in the pH range greater than 10. This study suggests that palladium concentrations in certain high-level waste repository environments may be limited by Pd metal and may be less than 10-9M.
Uncertainty and Sensitivity Analysis of Solubility Calculations at Elevated Temperatures
Authors: Ekberg C. , Skarnemark G. , Emrén A. T. , Lundèn I. 
Published: April 2011

AbstractComputer simulations are commonly used in many areas to obtain information about a system. It is, however, important to remember that the indata to these models are encumbered with errors of varying magnitude. To investigate the effect of these errors, a sensitivityuncertainty (s/u) analysis is often made.This paper focuses on how the solubility of a solid phase is affected by uncertainties in the enthalpy of reaction for the species present in the solvent. Usually, thermodynamic data are given for a temperature of 25°C, but calculations are not made at this temperature for many practical applications. It is interesting to know which enthalpies are important and how much given uncertainties in these enthalpies affect the calculated solubility of a solid phase.The solubility calculations were performed by the thermodynamic equilibrium program PHREEQE and the statistical evaluations with a modified version of the SENVAR program.The solubility of e.g. UO3-2H2O at 80°C was investigated. The conclusion was that the solubility ranged from lE-05 to 4.5E-06 when the enthalpies of reaction for the interesting species were changed within a four kcal/mole wide interval. The maximum solubility, based on an arbitrary distribution, was found to be no greater than 9E-05 with 95% confidence.
Preliminary Analysis of Important Site-Specific Dose Assessment Parameters and Exposure Pathways Applicable to a Groundwater Release Scenario at Yucca Mountain
Authors: Laplante P. A. , Maheras S. J. , Jarzemba M. S. 
Published: April 2011

AbstractTo develop capabilities for compliance determination, the Nuclear Regulatory Commission (NRC) conducts total system performance assessment (TSPA) for the proposed repository at Yucca Mountain (YM) in an iterative manner. Because the new Environmental Protection Agency (EPA) standard for YM may set a dose or risk limit, an auxiliary study was conducted to develop estimates of site-specific dose assessment parameters for future TSPAs. YM site-relevant data was obtained for irrigation, agriculture, resuspension, crop interception, and soil. A Monte Carlo based importance analysis was used to identify predominant parameters for the groundwater pathway. In this analysis, the GENII-S code generated individual annual total effective dose equivalents (TEDEs) for 20 nuclides and 43 sampled parameters based upon unit groundwater concentrations. Scatter plots and correlation results indicate the crop interception fraction, food transfer factors, consumption rates, and irrigation rate are correlated with TEDEs for specific nuclides. Influential parameter groups correspond to expected pathway behavior of specific nuclides. Results for nuclides that transfer more readily to plants, such as 99Tc, indicate crop ingestion pathway parameters are most highly correlated with the TEDE, and those that transfer to milk (59Ni) or beef (79Se, 129I, 135Cs, 137Cs) show predominant correlations with animal product ingestion pathway parameters. Such relationships provide useful insight to important parameters and exposure pathways applicable to doses from specific nuclides.
Disposal of Aluminum Based Spent Fuels in a Repository
Authors: Louthan M. R. , Iyer N. C. , Sindelar R. L. , Peacock H. B. 
Published: April 2011

AbstractAluminum clad fuel and target elements represent approximately 10% of the DOE owned spent nuclear fuels. The uranium in a large fraction of these fuels is highly enriched and is present as uraniumaluminides which are distributed relatively uniformly within an Al-U alloy core. Emerging acceptance criteria are expected to limit the dry storage temperature for aluminum based fuels to approximately 200°C. The rock temperature near the center of a repository may exceed 200°C if the thermal loading approaches 110 kW/acre. This combination may force the placement of canisters containing aluminum based fuels near the repository periphery. The warm, moist environment anticipated at the periphery may provide aggressive conditions for corrosion of the canister and the highly enriched, aluminum based fuels. Peripheral locations may also be the most vulnerable to covert fuel removal operations. Possible consequences of mixing aluminum based fuels with other fuels in a repository are discussed in this paper.
Symmetrically Configured AC Light-Emitting (Scale) Devices: Generalizations and Variations
Authors: Wang Y. Z. , Gebler D. D. , Epstein A. J. , Wang H. L. , Swager T. M. , Macdiarmid A. G. 
Published: April 2011

ABSTRACTMost conjugated polymer-based light-emitting devices have been shown to be tunnel diodes which can only operate under forward DC driving field. Recently we have reported the fabrication of symmetrically configured AC light-emitting (SCALE) devices based on heterocyclic aromatic conjugated polymers. By adding an “insulating” layer (e.g. emeraldine base (EB) form of polyaniline) on both sides of the emitting layer, the SCALE devices emit light under both forward and reverse DC bias as well as AC driving voltage. The SCALE device structure ITO/J/emitterFl/M, has been shown to be quite general, and can be applied to a variety of electroluminescent polymers (emitter), insulating polymers (I) and electrode materials (M). Here we summarize and compare the performance of SCALE devices fabricated with different emitter, insulator, and electrode materials. The role of the insulating layer in the SCALE device operation is examined and a model that emphasizing the interface states is proposed to account for the device operation.
Molecular Beam Deposition of Organic Nonlinear Optical Materials
Authors: Schlesser R. , Dietrich T. , Sitar Z. , Günter P. 
Published: April 2011

ABSTRACTThin films of the organic nonlinear optical materials 4‘-nitrobenzylidene-3-acetamino-4- methoxy-aniline (MNBA), and 2-cyclooctylamino-5-nitropyridine (COANP) have been deposited by organic molecular beam epitaxy. Homoepitaxial growth has been demonstrated for both materials. MNBA thin films were grown heteroepitaxially on lattice-matched ethylenediammonium terephthalate (EDT) substrates. Under optimum growth conditions, similar to those valid for homoepitaxial growth of the same material, i.e. at substrate temperatures of 80°C, and growth rates of 0.1 Å/s, highly oriented films were deposited in an island growth mode. Nonlinear optical second-harmonic generation experiments confirmed the macroscopic orientation of the deposited MNBA thin films. Growth experiments with MNBA and COANP on inorganic substrates lead to amorphous or polycrystalline films, depending primarily on the substrate temperature. A spontaneous recrystallization process, occurring in COANP thin films under ambiant conditions, led to the formation of macroscopic nonlinear optically active domain structures.
Second Harmonic Generation in Poled Polymers
Authors: Stegeman G. I. , JÄger M. , Otomo A. , Brinker W. , Yilmaz S. , Bauer S. , Horsthuis W. H. G. , MÖhlmann G. R. 
Published: April 2011

ABSTRACTThe phenomenon of second harmonic generation has been studied from the earliest days of nonlinear optics.[l] To date the most impressive results in terms of conversion efficiency for as low an input power as possible have been obtained in channel waveguides made from inorganic materials.[2] However, when their second order nonlinearities (10s of pm/V) are compared with those of organic materials (10s → 100s pmn/V), it is clear that organic materials should eventually produce much better harmonic conversion efficiencies. [3]
Design of New Copolymers for Photonics Applications: Incorporation of Nlo-Active Chromophores with Well-Defined Conjugation Lengths
Authors: Spangler Charles W. , He Mingqian 
Published: April 2011

ABSTRACTElectroactive polymers such as poly [p-phenylene vinylene] (PPV) and poly [2,5-thienylene vinylene] (PTV) have been shown to yield highly conductive materials upon oxidative doping,1 and to display enhanced third order nonlinear optical response.2 Optical absorption spectra for either neutral or doped polymers, however, are quite broad, extending well into the visible for the neutral polymer and into the near infrared (NIR) for the doped polymers, with little evident fine structure. For certain nonlinear optical (NLO) applications, this can lead to undesirable absorption losses and resonance phenomena. We would like to describe how copolymers incorporating oligomeric dithienylpolyene segments may be designed so as to give some degree of control over the polymer absorption characteristics in either neutral or oxidized form.
Frenkel Biexcitons in 1D J-aggregates
Authors: Spano Frank C. , Manas Eric S. 
Published: April 2011

ABSTRACTWe calculate the pump-probe spectrum of an ensemble of ID molecular aggregates, taking into account coherent exciton transport and exciton-exciton interactions. Comparison with recent experiments show that small radius biexcitons may be optically induced in PIC J-aggregates.
Epoxy Based Non-Linear Optical Polymers Functionalized With Chromophores Containing Tricyanovinyl Group
Authors: Wang Xiaogong , Chen Jeng-I , Marturunkakul Sutiyao , Li Lian , Kumar Jayant , Tripathy Sukant K. 
Published: April 2011

ABSTRACTTwo types of second-order nonlinear optical epoxy-based polymers functionalized with tricyanovinyl chromophores were synthesized. One was prepared by azo coupling between an epoxy prepolymer and 4-tricyanovinylaniline while the other was synthesized by reacting the epoxy prepolymer with tetracyanoethylene. The d33 for the polymers were determined to be 243 and 178 pm/V at 1.064 μm respectively. Retentions of deff value of 83% and 65% were observed after the polymers had been heated at 80°C for 1000 hours.
Application Of Thin Films Of Conjugated Polymers In Novel Led's And Liquid Crystal “Light Valves”
Authors: Macdiarmid A. G. , Wang H. L. , Huang F. , Avlyanov J. K. , Wang P. C. , Swager T. M. , Huang Z. , Epstein A. J. , Wang Y. , Gebler D. D. , Shashidhar R. , Calvert J. M. , Crawford R. J. , Vargo T. G. , Whitesides G. M. , Xia Y. , Hsieh B. R. 
Published: April 2011

ABSTRACTLight emitting electroluminescent devices have been studied in which the conjugated light emitting polymer is separated on both sides from the device electrodes by a film of nonconducting polyaniline. The devices operate under an AC applied potential.Aluminum, copper or gold serve as the metal electrodes. Flexible, completely organic polymer dispersed liquid crystal light valves have been fabricated from transparent plastic substrates on which a conducting film of polypyrrole has been deposited. A new concept, “microcontact printing”, is being investigated for patterning the polypyrrole.
Fabrication And Characterization Of Polyimide Waveguides For Optical Interconnection
Authors: Robitaille L. , Callender C. L. , Noad J. P. 
Published: April 2011

ABSTRACTThis paper reports the fabrication and characterization of polyimide branching waveguides for on-chip optical signal distribution in GaAs-based optoelectronic integrated circuits (OEICs). Low-loss polyimide s-bends and splitters with good splitting ratios and angles considerably larger than similar structures made from inorganic (e.g. LiNbO3) and semiconductor (e.g. GaAs, InP) materials, have been successfully fabricated and tested. The effects of the radius of curvature, splitter angle and cladding materials on the optical losses are discussed.
Infrared Switching Polymer Dispersed Liquid Crystals
Authors: Moody R. A. , Loh I. H. , Hed A. Z. 
Published: April 2011

ABSTRACTInfrared Polymer Dispersed Liquid Crystals (PDLCs) - polymethylmethacrylate host and E7 eutectic liquid crystal mixture - are formed through an adaptation of the thermally induced phase separation process, enabling facile creation of large liquid crystal droplet formation in the polymer host outside of the normal thermodynamic limits. The PDLCs were characterized electro-optically and microscopically. The effects of the processing parameters on the droplet morphology and switching efficiency are analyzed and presented for these systems. Droplet sizes up to 15 &m have been observed with efficient switching characteristics in the 3 - 5 μm range.
Design and synthesis of ferroelectric liquid crystals. 24. Incorporation of the disperse red 1 chromophqre into side-by-side dimers for nonlinear optics
Authors: Dyer Daniel J. , Shao Renfan , Clark Noel A. , Walba David M. 
Published: April 2011

ABSTRACTWith excellent processibility on silicon integrated circuits and thermodynamically stable polar order, ferroelectric liquid crystals (FLCs) show great potential as components of fast integrated electro-optic modulators. In order to realize this potential, however, an increase in the magnitude of the electronic secona order nonlinear susceptibility χ(2) is required. This has been problematical since functional arrays with large molecular second order susceptibility β orient with improper supermolecular stereocontrol (i.e. with the charge transfer axis normal to the polar axis) when incorporated into traditional FLC structures. Herein we present examples of a new LC structural class designed to achieve the proper supermolecular structure for large χ(2) in FLCs. The observed sign and magnitude of the ferroelectric polarization of the new mesogens extrapolated from smectic C* mixtures is fully consistent with the desired supermolecular structure.
Investigations of New Self-Assembled Multilayer Thin Films Based on Alternately Adsorbed Layers of Polyelectrolytes and Functional Dye Molecules
Authors: Yoo Dongsik , Lee Jin-kyu , Rubner M. F. 
Published: April 2011

ABSTRACTThe layer-by-layer self-assembly of a number of different functional dye molecules has been accomplished via the alternate spontaneous adsorption of polyelectrolytes and ionic dyes from dilute solutions. Multilayer thin films containing such functional dyes as pH indicator dyes, infrared absorbing dyes, porphyrin dyes and various fluorescent dyes have been successfully fabricated and their electrical and opt, 2al properties examined. Multilayers containing a newly synthesized ionic ruthenium based polypryidyl dye have been utilized to fabricate light emitting thin film devices with high brightness (ca. 100 cd/m2) at voltages in the range of 5–10 volts. These new light emitting thin film devices exhibit excellent stability when compared to devices based on conjugated polymers such PPV. The fabrication and device evaluation of new heterostructure thin films based on this new light emitting dye as well as the properties of other multilayer thin films containing dye molecules are presented.
Polymer Nanocomposites of Surface-Functionalized Gold
Authors: Gonsalves K. E. , Carlson G. , Kumar J. , Aranda F. 
Published: April 2011

ABSTRACTNanometric gold particles were synthesized by a liquid/liquid phase-transfer reaction. Composites of these particles in polystyrene, poly(methyl methacrylate) and poly(phenylmethylsilane) were prepared at concentrations from 1.0 to 5.0 mg/ml were prepared, with no noticeable agglomeration of particles during processing. These materials showed a linear absorption peak at 530 nm, which is characteristic of nanosized gold. Highresolution electron microscopy measurement showed that the particle diameters were approximately 2.2 ± 1.3 nm. Degenerate four-wave mixing experiments at 532 nm yielded, on 10-micron films, a maximum value of 1.5 × 10−10 e.s.u. for the third-order nonlinear optical susceptibility.
Ladder Polymers of High Stability With Macrocyclic Metal Complexes as Subunits
Authors: Hanack M. , Hauschel B. , Stihler P. , Rack M. , Linßen T. 
Published: April 2011

ABSTRACTMacrocyclic bis-dienes and a diendienophile were prepared in Diels-Alder reactions starting from the bis-dienophilic (hemiporphyrazinato)nickel complex 1. 1 was reacted either with the tetraene 2 or with tetraphenylcyclopentadienone (4). By combination of macrocyclic bisdienes and bis-dienophiles, ladder-type oligomers were synthesized. They are precursors to the corresponding conjugated molecules, which are of interest as potential organic conductors. Monofunctional and bifunctional dienophilic macrocycles were also allowed to react with [60]fullerene to give the corresponding mono- and bis-fullerene adducts.
N-Substituted and Ring-Substituted Water Soluble Self-Aciddoped Conducting Polyanilines and their Blends with Poly(Vinyl Alcohol): Structure, Properties, and Applications
Authors: Chen Show-An , Hwang Gue-Wuu , Chuang Kuen-Ru , Shyb Shyi-Long , Loong Wen-An 
Published: April 2011

ABSTRACTThe water-soluble self-acid-doped conducting polyanilines, poly(aniline-co-Npropanesulfonic acid aniline) (PAPSAH) and sulfonic acid ring substituted polyaniline (SPAN), in aqueous solutions at full concentration range are characterized. The PAPSAH and SPAN can be cast into free standing films from their aqueous solutions and have the doping level, about 0.3. Their conductivities at room temperature are about the same (10−2 S/cm). As temperature increases, conductivities of PAPSAH and SPAN increase to the maxima about 10−1 S/cm at 110°C and 190°C respectively. Above these temperatures, their conductivities drop resulting from thermal undoping accompanying with a loss of some polarons. The incorporation of PVA into PAPSAH and SPAN provides excellent flexibility and only slightly decreased conductivity (10−3 S/cm at equal weight %). Applications of these two polymers and their blends in electron beam lithography and light emitting diode are studied.
Light Emitting thin Film Devices Based on Self-assembled Multilayer Heterostructures of PPV
Authors: Ferreira M. , Onitsuka O. , Fou A. C. , Hsieh B. , Rubner M. F. 
Published: April 2011

ABSTRACTPPV based light emitting thin film devices were fabricated using a layer-by-layer deposition technique involving the alternate spontaneous adsorption of a PPV precursor polymer and either poly(styrene-4-sulfonate) (SPS) or poly(methacrylic acid) (PMA). It was demonstrated that the polyanion used to self-assemble the PPV precursor strongly influences the characteristics and performance of the resulting LEDs. Devices fabricated with PPV created in the presence of SPS exhibited symmetric I–V curves, low luminance levels and very high current densities while PPV/PMA devices exhibited luminance levels in the range of 10–60 cd/m2 and classical rectifying behavior. These dramatic differences are primarily due to a low level of p-type doping activated during the thermal conversion of PPV and/or during device operation that confers excellent hole carrier transport capabilities to the PPV/SPS combination. Fabrication of a multi-slab type heterostructure device comprised of a PPV/SPS block (hole transporting block) and a PPV/PMA block (emitting block) resulted in improved performance with luminance levels significantly higher than previously obtained for a single slab PPV/PMA device (typically > 100 cd/m2). It was also demonstrated that the presence of very thin (about 20–30 Å thick) insulating layers at the Al/polymer interface improves device efficiency by a factor of 2–4.
Synthesis of Oligomeric P-Phenyleneimine by Self-Condensation Reaction of a Novel Monomer
Authors: Afzali A. , Gelorme J. D. 
Published: April 2011

ABSTRACTA new approach for the synthesis of poly(phenylenimines) and related conjugated polymers is presented. A novel bifunctional monomer, N-Boc-indoaniline 4 is synthesized as shown in scheme I. Thermolysis of the latter, either as solid, thin film or in solution of high boiling solvents, leads to polycondensation of the bifucntional monomer and results in the formation of poly(phenyleneimine) or its reduced form. Scope and limitation of this approach in the synthesis of various poly(aryleneimines) is also described.
Poly- and Oligoaniline Thin Films: Charge Transport, Optical Properties and Effect of Doping
Authors: Paloheimo J. , Pal A. J. , Stubb H. , Granholm P. , Isotalo H. 
Published: April 2011

ABSTRACTWe report a study of the electrical and optical properties of thin films of tetraanilinobenzene (TAB) and polyaniline (PANI) deposited using the Langmuir-Blodgett (LB), layer-by-layer selfassembly and vacuum-evaporation techniques. The paper will mainly concentrate on TAB LB films, but also results for other films are presented for comparison. The optical studies of undoped TAB LB films indicate H-aggregates. Upon doping new polaronic absorption bands appear and the photoluminescence of TAB becomes quenched. Doped LB and self-assembled films can reach conductivities up to about 10−4/cm for TAB and a few S/cm for PANT. The conductivity has a temperature dependence logσ α T−1/2, suggesting variable-range hopping in a quasi-gap, possibly due to the Coulomb interactions between localized carriers.
New materials for Organic Light-Emitting Diodes
Authors: Jacobs S. Joshua , Pollagi Timothy P. , Sinclair Michael B. , Scurlock Rodger D. , Ogilby Peter R. 
Published: April 2011

ABSTRACTWe have investigated the performance of a class of heterocycles, 5,10-dihetera- 5,10-dihydroindeno[3,2b]indenes, as hole transport agents in simple double heterostructure organic light-emitting diodes with tris(8-hydroxyquinoline)aluminum (Alq). The best of these materials, 5,10-dihydroindolo[3,2b]indole, yields devices with luminance and lifetimes comparable to those obtained using N,N′-di-(3-methylphenyl)-N,N′- diphenyl-4,4′-diaminobiphenyl (TPD) as a hole transporting material.