bluuebunny/crossref_metadata_2025 huggingface dataset:
Phellinus (Fomes) pini decay associated with sweetfern rust in sapwood of jack pine
Authors: Blanchette Robert A.
Published: February 2010

Phellinus (Fomes) pini (Thore ex Fr.) A. Ames was associated with cankers and discolored wood caused by the rust fungus Cronartiumcomptoniae Arth. in sapwood of young jack pines (Pinusbanksiana Lamb.). Patterns of decay throughout the tree were influenced by the severity of rust-induced cankers. Fifteen trees 17 to 42 years old and 3 trees 78 to 81 years old with basal cankers of C. comptoniae and sporophores of P. pini were examined macroscopically with a video processor image analyzer and microscopically with scanning electron microscopy. The average length of the discoloration and decay columns was 5.19 m. The twisted and shortened tracheids of cankered sapwood restricted the growth of P. pini. The greatest volume of defect was located above the canker. Scanning electron microscopy demonstrated a localized delignification of the altered sapwood. Degraded areas were separated from unaltered wood by resin-filled tracheids. The youngest jack pine with sporophores of P. pini was a 17-year-old tree.
A probabilistic model relating stocking to degree of scarification and aerial seeding rate
Authors: Régnière Jacques
Published: February 2010

A probabilistic model is developed which relates stocking to degree of scarification and aerial seeding rate. Seed deposition patterns resulting from air turbulence and aircraft motion, as well as variability in seedbed distribution across a seeding chance, are shown to decrease potential stocking. The model is validated by comparison with experimental data on jack pine, using nonlinear regression. A set of equations is developed which enables selection of prescriptions for degree of scarification and seeding rates required to achieve desired stocking levels.
Rotten wood as mycorrhizal inoculum for containerized western hemlock
Authors: Kropp Bradley R.
Published: February 2010

Rotten wood served as mycorrhizal inoculum for containerized western hemlock seedlings. Rotten wood from a clear-cutting was less effective than that collected from a forest. Mycorrhizal colonization was slow under the experimental conditions, probably because of the heavy fertilization typical of container operations. No pathogens appeared on seedlings grown on either source of wood.
Barking damage by snowshoe hares and red squirrels in lodgepole pine stands in central British Columbia
Authors: Sullivan Thomas P. , Sullivan Druscilla S.
Published: February 2010

Barking damage by snowshoe hares (Lepusamericanus Erxleben) and red squirrels (Tamiasciurushudsonicus Erxleben) is common in overstocked stands of juvenile lodgepole pine (Pinusconforta Dougl.) in central British Columbia. Average proportion of potential crop trees damaged by hares was 30.0% and by squirrels was 37.7%. Most hare feeding injuries occurred in heavily stocked (> 20 000 stems/ha) stands, whereas squirrel damage was most common in less dense stands. Both animal species damaged trees in thinned stands, and hence may have a serious impact on stocking control programs in lodgepole pine.
Prediction of bud burst in Douglas-fir by degree-day accumulation
Authors: Thomson A. J. , Moncrieff S. M.
Published: February 2010

A temperature threshold, starting date, and heat unit total are required for use of degree-days. The three parameters are not independent, the heat unit total depending largely on the threshold used. An iterative solution is presented to estimate these parameters for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) bud burst from observations of flush dates and weather station records. The estimates obtained predicted average flush date and first bud burst ± 1 day in 80% of years for a 10-year period for a group of 154 Douglas-fir trees. Date of first and last tree flush were predicted ± 1 day in 50 and 60% of years, respectively. Sensitivity analysis indicates that the threshold and starting date can be varied to a considerable extent without influencing the accuracy of the predictions.
The use of production-function analysis in forest management: eucalypts in Brazil, a case study
Authors: Nautiyal J. C. , Couto L.
Published: February 2010

Production-function analysis is applied to data from a spacing research carried out for a hybrid of Eucalyptusurophylla S.T. Blake in Brazil. A logarithmic –reciprocal equation is chosen as the best fitting production function for the present data, and its elasticities of production, elasticity of scale, and elasticity of substitution are computed. Given the production function, the set of input quantities which maximize the present net worth of an infinite number of forest cycles for a range of discount rates is presented.
Challenges in Correlating In Vitro Corrosion Data to In Vivo Performance for Implantable Electrode Materials
Authors: Martinez Gonzalo
Published: February 2010

Standard in vitro tests are useful to identify corrosion susceptibility, material heterogeneity, and basic corrosion byproduct toxic screening. However, those tests do not adequately account for important interactions between the device, the material and the implant host. In vivo processes such as fibrotic tissue encapsulation of implanted electrodes modulate current density distribution effects and thus influence local dissolution rates and charge injection. Electrode and conductor transient effects such as potential and current excursions may be important, or may have minimal effect in the implanted system. Corrosion byproducts of local microenvironments can have a profound effect in the stability of adjacent materials, i.e., metal induced oxidation (MIO) of polyurethanes. Those effects can be mitigated via appropriate design and selection of materials. Corrosion test data analysis should include a system level risk assessment with full awareness of in vivo use, and an estimation of corrosion effect propagation, no matter how small the individual component effects may be.
Electrochemical Properties and Biological Activity of Carbon Materials Modified by Polypyrrole
Authors: Khubutiya Mogely , Goldin Mark , Stepanov Andrey , Hall Peter , Kolesnikov Vladimir , Volkov Alexander
Published: February 2010

Prospects of development of an electrochemically controlled hemosorption detoxification method are very promising because this method combines biocompatibility of activated carbon with high adsorptivity towards toxic compounds. The present work is an attempt to develop controlled detoxification processes on carbon adsorbents modified by electroconductive polypyrrole. Electropolymerization of pyrrole on activated carbon AG-3 had added biocompatibility to a material that is aggressive towards blood. The magnitude and direction of open circuit potential (OCP) shifts for the carbon materials studied depend on the conditions of electropolymerization. Adsorptivity of AG-3 covered by polypyrrole was increased compared with untreated carbon.
Electrochemical Etching of NiTi Alloy in a Neutral Fluoride Solution
Authors: Cattarin Sandro , Guerriero Paolo , Musiani Marco , Tuissi Ausonio , Vázquez-Gómez Lourdes
Published: February 2010

Electrochemical etching of NiTi alloy in a pH 6 fluoride solution is proposed as a convenient alternative to chemical etching in oxidizing HF media. Anodization produces protons at the electrode surface, and local acidification increases the concentration of HF that efficiently dissolves the surface oxides, promoting a sustained dissolution current that decreases with increasing mass-transfer rate. The voltammetric pattern includes a "pseudoplateau" at low potentials, in which only a metal dissolution takes place, and a steady current increase at higher potentials due to the onset of oxygen evolution. The treatment produces a semilustrous rough surface, showing a structure of shallow microscopic cavities in SEM images. EIS spectra recorded in the pseudoplateau region are similar to those observed during anodic polarization of Ti in HF and their analysis indicates formation of a thin barrier film of thickness increasing linearly with potential.
Ionic Liquid Electropolishing of Metal Alloys for Biomedical Applications
Authors: Abdel-Fattah Tarek M. , Loftis Jon Derek , Mahapatro Anil
Published: February 2010

Biomedical alloys such as Nitinol (nickel-titanium), cobalt-chrome, and 316L stainless steel were successfully electropolished via an ecologically-friendly ionic liquid medium formed from vitamin-B4. Voltammetry and chronoamperometry tests determined optimum polishing conditions for each alloy. A digital microscope provided surface morphology comparisons to benchmark success of each electropolishing test. Energy dispersive X-ray analysis (EDX) was utilized to report % composition of each alloy surveyed before and after each non-acid electrochemical polishing experiment.
Electrochemical Micro Technologies for Polymeric MEMS and Biochip Applications
Authors: Ofek Almog Rakefet , Sverdlov Yelena , Fishelson Nick , Shmilovich Tsvi , Rabinovich Emma , Shacham-Diamand Yosi Y.
Published: February 2010

Flexible electrode chips were fabricated on polymer substrates, either SU-8 (epoxy-based photo-definable polymer) or PDMS (Polydimethylsiloxane, elastomer-base polymer), using a photolithography process. In one case, Ppy (Polypyrrole, a conductive polymer) was deposited on the electrodes' gold seed layer. In another case, Ppy was deposited on the micro actuator's copper seed layer, both cases by electropolymerization using cyclic voltammetry. Thus, we developed a process for a flexible electrode that integrates a polymer substrate and a conductive polymer. The polypyrrole is reinforcing the Gold and Copper wires and electrically shunting the interconnects, increasing thereby the device durability and reliability.
Biologically Closed Electrical Circuits in Plants
Authors: Foster Justin C. , Volkov Alexander , Markin Vladislav S.
Published: February 2010

The Venus flytrap is a marvel of plant bioelectrochemical engineering. The rapid closure of the Venus flytrap upper leaf in about 0.1 s is one of the fastest movements in the plant kingdom. We found earlier that the electrical stimulus between a midrib and a lobe closes the Venus flytrap upper leaf without mechanical stimulation of trigger hairs. Thigmonastic movements in the Venus flytrap, associated with fast responses to environmental stimuli, appear to be regulated through electrical signal transductions. The thigmonastic responses of the Venus flytrap can be considered in three stages: stimulus perception, electrical signal transmission, and induction of mechanical, hydrodynamical and biochemical responses. The hydroelastic curvature mechanism closely describes the kinetics of leaf movements. The electrical properties of the Venus flytrap were investigated and an equivalent electrical circuit was proposed that explains the experimental data.
In Situ Micro-Raman Studies of Syringaldazine-entrapped Composite Electrodes Modified with Laccase
Authors: Żukowska Grażyna Z. , Nogala Wojciech , Svartsov Yuriy , Marcinek Marek , Rogalski Jerzy , Szot Katarzyna , Opałło Marcin
Published: February 2010

Raman spectroscopy studies of oxidation of 3,5-dimethoxy-4-hydroxybenzaldehydrazine (syringaldazine) encapsulated in silica and composite carbon electrodes were performed. The presence of reduced and oxidized forms of syringaldazine present at various potentials was determined using Raman spectroscopy. The structure of the oxidized form was discussed on the basis of theoretically predicted spectra. A comparison of Raman spectra of syringaldazine oxidized electrochemically and in reaction with laccase from Cerrena unicolor encapsulated within a thin hydrophilic silicate film on the electrode surface shows presence of two oxidized forms of the former, while only one form was detected in the laccase containing electrodes.
Light Management for Efficient Crystalline Si Heterojunction Solar Cells
Authors: Wang Qi , Page Matt , Iwaniczko Eugene , Xu Yueqin , Hasoon Falah
Published: February 2010

High efficiency crystalline Si heterojunction solar cells have been achieved with an independently-confirmed efficiency of 19.3% on a p-type silicon wafer. The hydrogenated amorphous silicon (a-Si:H) emitter and back contact were deposited using high-rate hot-wire chemical vapor deposition. This high efficiency cell has an open circuit voltage of 0.678 V, fill factor of 78.6%, and short circuit current density of 36.2 mA/cm2. Improved surface texturing, surface cleaning, back contacts, indium tin oxide (ITO) thickness, and surface passivation all contribute to the high efficiency. The high open circuit voltage results from the good amorphous Si surface passivation with a minority carrier lifetime of ~ 1 ms. Light management was applied to further improve the cell performance. ITO layer was optimized to maximize the current collection. This layer acts as a transparent contact layer to the emitter as well as a single anti-reflectance layer to minimize the optical loss due to reflection.
Synthesis and Characterization of CuInSe2 Thin Films by Annealing of Electrodeposited In2Se3/Cu and In2Se3/CuxSey Stacks
Authors: Fischer Johannes , Siebentritt Susanne , Dale Phillip J.
Published: February 2010

CuInSe2 (CIS) thin films were successfully formed by annealing of electrodeposited In2Se3/CuxSey and In2Se3/Cu stacks. Conditions for the uniform and stoichiometric electrodeposition of In2Se3, Cu, and CuxSey thin layers are presented. Phase evolution during the annealing is studied by XRD for several temperatures. SEM cross sections show recrystallization during annealing for the copper selenide containing precursor. The photoelectrochemical response of the absorber is weaker compared to coelectrodeposited CIS and requires further improvement.
Fullerene-Based Materials as Catalysts for Fuel Cells
Authors: Gabriel Margaret A. , Deutsch Thierry , Franco Alejandro A.
Published: February 2010

Nano-structured catalyst degradation in state-of-the-art polymer electrolyte membrane fuel cells (PEMFCs) is one of the main shortcomings that limit the large-scale development and commercialization of this technology. During normal operating conditions of the fuel cell, the PEMFC lifetime tends to be limited by coarsening of the cathode's Pt-based catalyst and by corrosion of the cathode's carbon black support. Because of their chemical properties, metallofullerenes, such as C59Pt or PtC60, may be more electrochemically stable than the Pt/C mixture. In this paper we investigate, by theoretical methods, the stability of oxygen reduction reaction (ORR) adsorbates on these metallofullerenes.
A Study of Artificial Neural Networks for Electrochemical Data Analysis
Authors: Hsueh Kan-Lin
Published: February 2010

Artificial neural network has been demonstrated the capability of identifying the chemical composition from various analytical methods. This study tested the feasibility of using a single network to calculate data obtained from polarography, linear scanning voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). Computer generated data were used for network learning and testing. The network property of a single layer network was calculated at various learning cycles, learning rates, and β values of the neuron activation function. This study also evaluated two-layer, three-layer, and four-layer networks. Test results conclude that a single artificial neural network could analyze various analytical data by using corresponding weight matrices. To produce accurate results, the network requires high training cycle, small β value of sigmoid function, and small learning rate. Network accuracy increase as the number of neuron increased to certain extents. Network structure plays minimum effects on the accuracy of network for a given number of neurons.
A Comparative Electrochemical Study on Arsenic Removal Using Iron, Aluminum, and Copper Electrodes
Authors: Gomes Jewel A. , Rahman Md. Sanoar , Das Kamol , Varma Srikanth , Cocke David
Published: February 2010

Arsenic is considered as one of the toxic materials being controlled by environmental protection agencies in several developed and developing countries. It is found in the nature as constituents of the soil, minerals and also in various organic forms. It enters the air, water, and land from wind-blown dust and gets into water from runoff, leaching, soil erosion and anthropogenically from chemicals used for wood preservation, insecticides, medicine, military purpose, pigments, and electronic circuitries. There are several techniques available for removal of arsenic, such as coagulation/filtration, lime softening, ion exchange, reverse osmosis, nanofiltration, wet chemical, and electrochemical. Electrocoagulation has been found as one of the most efficient techniques to remove inorganic arsenic with more than 99% efficiency. In this paper, we present our work on electrochemical treatment of both the inorganic and organic arsenic from water using various sacrificial electrode materials, i.e., iron, aluminum, copper, and combination of them. The floc produced by this method has been also characterized using XRD, SEM/EDS, and cyclic voltammetry.
Reactivity of Electrogenerated Imidazole-2-Ylidenes in Ionic Liquids: Synthetic Implications
Authors: Feroci Marta , Chiarotto Isabella , Orsini Monica , Sotgiu Giovanni , Inesi Achille
Published: February 2010

The cathodic reduction of an imidazolium ionic liquid, under galvanostatic conditions, leads to the formation of the corresponding carbene, imidazole-2-ylidene, and molecular hydrogen. This carbene can behave as a base and/or as a nucleophile, depending on the reaction partner. In particular, we have studied the reactivity of this N-heterocyclic carbene in alkylation and acylation reactions, in the synthesis of β-lactams, in the Henry reaction, in the synthesis of thiones and in the benzoin condensation
Neutral H2O2 Synthesis by Electrolysis of O2 and Water
Authors: Murayama Toru , Yamanaka Ichiro
Published: February 2010

On-site production method of neutral H2O2 solution by electrolysis of O2 and water was investigated. Improved SPE (solid-polymer-electrolyte) electrolysis method was applied for the synthesis of neutral H2O2 solution. We found that exposure of a cathode of the SPE electrolysis in O2 stream (1 atm) was efficient for the neutral H2O2 formation (Exp-SPE method). A cathode prepared from oxidized activated carbon, vapor-grown carbon fiber and PTFE, and coating with Nafion solution was the most active for neutral H2O2 formation. The neutral H2O2 solution of 8 wt% was continuously produced with 27% CE at -0.3 V (Ag/AgCl) by the Exp-SPE method.
Chrysene Derivatives as New Organic Semiconductors for Organic Field-effect Transistors
Authors: Kunugi Yoshihito , Ikari Mitsuaki , Okamoto Kazuo
Published: February 2010

Organic field-effect transistors based on vapor deposited films of 2,8-dioctylchrysene (C8-CR), 2,8-diphenylchrysene (Ph-CR), 2,8-dinaphthylchrysene (Nap-CR) and 2,8-bis(octylstyryl)chrysene (C8S-CR) were successfully fabricated. All the chrysene derivatives based OFETs showed typical p-channel FET characteristics, and the best field-effect mobility of 4.1 x 10^-2 cm^2V^-1s^-1 with on/off current ratio of 10^5 was obtained for the Ph-CR based OFET. Interestingly, the field-effect characteristics were strongly affected by substrate temperatures (Tsub). According to the AFM and XRD measurements, molecular packing and morphology of the deposited films were drastically changed by substrate temperatures.
Effect of Alkaline-Earth Additives on Wetting Characteristics in Li/Na Molten Carbonate Electrolyte
Authors: Hsieh Ping-Hsun , Selman J. Robert
Published: February 2010

The effect of alkaline-earth additives on wetting characteristics of gold electrode by Li/Na carbonate electrolyte under MCFC operating conditions has been studied. The addition of alkaline-earth carbonates decreases the wettability of the electrolyte at open circuit. When an electrochemical process takes place, the basicity of the melt and ionic mobilities of cations may have an appreciable effect on the contact angle. If the electrode process is cathodic, the movement of ionic species causes increased wetting, which may facilitate the process. For example, in the case of cathodic oxygen reduction, polarization is decreased. In general, the wetting, i.e., contact angle, under polarization result from superimposition of thermodynamic (electrocapillary) and transport effects.
Design of Direct Methanol Alkaline Fuel Cell with Anion Conductive Membrane Prepared by Plasma Polymerization
Authors: Sudoh Masao , Niimi Sachi , Takaoka Naohiro , Watanabe Masashi
Published: February 2010

Direct methanol alkaline fuel cells has been tested to suppress methanol crossover and to improve anodic activity in alkaline media. Plasma-polymerization with 4-vinylpridine and hexafluoropropene followed by quarternization using 1-bromopropane was conducted to prepare anion conductive ionomer in the catalyst layer and anion conductive membrane using porous film. The performance of direct methanol alkaline fuel cell with anion-conductive ionomer and membrane was compared with direct methanol fuel cell with proton exchange membrane at 60 {degree sign}C. The open circuit voltage using anion-conductive membrane was higher than using proton exchange membrane. Anion-conductive ionomer in catalyst layer improved cell performance. The water vapor in the cathode was starved by transport of electro-osmotic water with hydroxide anion. Plasma-polymerized membranes on various porous films were characterized by means of water uptake, ion conductivity and methanol permeability.
Chloromethylation of Poly(ether-imide) for Alkaline Fuel Cell Application
Authors: Wang Guigui , Weng Yiming , Xie Dong , Chu Deryn , Chen Rongrong
Published: February 2010

We have developed a novel alkaline anion exchange membrane derived from poly(ether-imide) for improved ionic conductivity. The effects of several important parameters including reaction temperature, time, concentration of chloromethylation agent, concentration of polymer and the amount of catalyst on chloromethylation of the membrane were investigated. The quaternization of the synthesized chloromethylated polymer was studied as well. The results show that all the studied parameters exhibited significant impacts on chloromethylation. Among them, the concentration of the chloromethylation agent played a key role in increasing the chloromethyl functional group attachment onto the polymer. Using an appropriate quaternization approach could significantly improve the ionic conductivity and optimize the conductivity of the membrane.
Influence of Carbon Dioxide on the Performance of Anion-Exchange Membrane Fuel Cells
Authors: Matsui Yu , Saito Morihiro , Tasaka Akimasa , Inaba Minoru
Published: February 2010

The influence of CO2 in the oxidant gas on the cell performance of anion-exchange membrane fuel cells was investigated using a three-electrode single cell with a reversible hydrogen electrode (RHE). The overpotential of the cathode was hardly changed by the presence of CO2, while the overpotential of the anode increased after the introduction of CO2 at the cathode. The high anode overpotential was caused by a high CO32- concentration in the anode catalyst layer, even when most of the CO32- ions in the electrolyte membrane are purged during operation through the self-purging mechanism.
Simultaneous Oxidation and Metal Dusting of Fe-Si Alloys
Authors: Motin Abdulla , Zhang Jianqiang , Young David J.
Published: February 2010

Pure iron and binary alloys containing 1, 2, 3 and 5 wt. % Si were reacted at 680oC with a carbon-supersaturated, flowing gas mixture of 68% CO, 26% H2 and 6% H2O (aC = 2.9, pO2 = 2 × 10-23 atm). Alloy reaction products consisted of a subsurface zone of internally precipitated SiO2, an external scale of Fe3C + SiO2, and a voluminous superficial deposit of coke containing particles of cementite and silica. Coking and metal dusting rates both increased with alloy silicon level. Internal oxidation rates also increased with silicon concentration, but net scaling rates decreased. It is proposed that increasing volume fractions of silica in the scale provide more sites for graphite nucleation, which leads to accelerated disintegration of the scale surface. This accounts for the more rapid dusting, faster coking (catalysed by more Fe3C particles) and thinner scales.
Combined Effect of High Temperature and VUV Radiation on Carbon-Based Materials
Authors: Eck Julien , Sans Jean-Louis , Balat-Pichelin Marianne
Published: February 2010

For the next exploration of the sun, missions like Solar Probe+ (NASA) or Phoibos (ESA) will be launched to answer to fundamental questions on the solar corona heating and solar winds origin. Such solar probes missions that will pass very close to the sun, respectively at 9.5 and 4 solar radii (Rs), need thermal shield to protect the payload and the instrumentation. Carbon/carbon composites can withstand the severe environment encountered during the pass of the sun and have to be studied to understand their physico-chemical behavior in these conditions. This paper presents numerical and experimental results on two carbon-based materials that could be used as thermal protection system for future solar probes.
High Temperature Oxidation of SiC under Helium with Low Oxygen Partial Pressure
Authors: Balat-Pichelin Marianne , Charpentier Ludovic , Audubert Fabienne
Published: February 2010

The Gas-cooled Fast Reactor (GFR) is one system of the Generation IV International Forum systems studied by CEA (France). The coolant considered is helium pressurized at 7 MPa and the nominal working temperature is about 1300 K. In case of accident, the reactor temperature can reach 1900 to 2300 K. Several studies are carried out to determine the physico-chemical behavior of structural materials undergoing various environmental constraints. The cladding material currently considered is SiC. Numerical calculations are carried out to determine the transition between passive and active oxidation regimes. Then an experimental study is performed to fix the position of the transition and to study the oxidation resistance of the two polymorphs α- and β-SiC at high temperature (1300 to 2300 K), coupled to a material characterization based on mass variation, SEM, XPS, AFM and roughness analyses.
Diffusion in High-Temperature Piezoelectric Single Crystals
Authors: Sauerwald Jan , Schulz Michal , Richter Denny , Fritze Holger
Published: February 2010

The high-temperature stability of the single crystalline piezoelec-tric material langasite and associated transport phenomena such as the diffusion of the constituents gallium and oxygen are investi-gated. Small structures remain their shape upon annealing at 1350°C for 24 h. The transport phenomena are in accordance with the defect model of langasite. In particular, oxygen is found to be the dominant ionic charge carrier. A newly developed concept based on monolithic structures in langasite is realized by local dop-ing with praseodymium, strontium and niobium. Those elements either increase the conductivity or modify the rate of wet chemical etching. In order to demonstrate the feasibility of monolithic elec-trodes, the operation of locally Sr-doped bulk acoustic resonators is presented. Further, the correlation of electromechanical properties and transport processes is investigated using langasite bulk acous-tic resonators. Doping by niobium lowers e. g. the total loss at high temperatures.
Liquid-Phase Oxidation Joining of Yttria-Stabilized Zirconia via Al/Fe-Cr Alloy/Al Interlayers
Authors: Akashi Takaya , Shimura Tsunahiro , Kiyono Hajime
Published: February 2010

Liquid-phase oxidation (LPO) joining technique was employed to join yttria-stabilized zirconia (YSZ) blocks using Al/Fe-Cr alloy /Al interlayer for development of a gas sealing technique for solid oxide fuel cells (SOFCs). The YSZ blocks were joined at 1073 to 1473 K for 3.6 to 28.8 ks in vacuum (< 0.2 Pa) with a stress of 80 MPa and annealed at 973 K for 3.6 ks in air. The average four-point bend strength and Weibull modulus of LPO-joined YSZ specimen increased with increasing joining time at 1273 K. The specimen joined at 1273 K for 28.8 ks has a four-point bend strength of 135 MPa, which was about four times greater than that obtained by brazing technique using Ag solder, and comparable to unbonded monolithic YSZ. Polycrystalline alumina layer, which is expected to act as an insulating and protective layer, was formed between YSZ and Fe-Cr alloy after the LPO joining.
Effect of Impurities (Oxides, Hydroxides) in Molten Salt Electrolytes on the Thermal Stability of FeS2 Cathode Material for Thermal Batteries
Authors: Masset Patrick J.
Published: February 2010

The thermal decomposition of pyrite FeS2 used as cathode material in thermal batteries was investigated under helium and in molten salts (eutectic compositions: LiCl-KCl and LiF-LiCl-LiI), in presence of hydroxides and oxides. This work shows the pyrite decomposes into pyrrhotite and forms a porous structure. It has been shown that the presence of a molten phase increases pyrites thermal stability as it acts as a physical barrier. On the other hand, the addition of hydroxide or oxide decreases its thermal stability. At high temperature hydroxides are transformed into oxides. The decomposition temperature of the pyrite in presence of oxides is decreased by nearly 70 to 100°C.
Self-Organized Crystal Growth of Nanostructured ZnO Morphologies by Hydrothermal Synthesis
Authors: Foe Kurniawan , Boland Patrick , Namkoong Gon , Gu Diefeng , Baumgart Helmut , Abdel-Fattah Tarek M.
Published: February 2010

A template-free method was developed to synthesize zinc oxide (ZnO) nanoflowers, nanorods, microdandelions, and microspheres using hydrothermal synthesis. The effect of pH value on ZnO morphology was investigated using zinc acetate dehydrate and urea as an additive. We found that ZnO microspheres were developed at pH=12.0 while nanoflowers and nanorods were developed at pH less than 11.0. Furthermore, we also found that urea plays a crucial role in the formation of ZnO microspheres.
Electrochemical Response and Surface Morphology of Metal Nanoparticles by Pulsed Laser Deposition
Authors: Ito Takeshi , Kaneko Satoru , Hirabayashi Yasuo , Soga Masayasu , Suzuki Koji
Published: February 2010

We studied electrochemical responses and morphologies of metal nanoparticles (MNPs) which were prepared by using pulsed laser deposition (PLD) method. Pt and NiO were deposited on a silicon (Si) and a grassy carbon (GC) substrate. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) images did not determine their nanoparticles. Auger Electron Spectroscopy (AES) and X ray Photoelectron Spectroscopy (XPS) for Pt and NiO coated Si substrates showed that MNPs were certainly formed. Pt with the deposition time of 60 sec had highest activity to detect hydrogen peroxide in phosphate buffer solution. NiO with the deposition time of 90 sec showed highest activity to detect glucose in sodium hydroxide solution. These characteristics might be caused by catalytic activity of MNPs.
Synthesis of Nickel-Carbon Nanohorn Composite Films by an Electrodeposition Technique
Authors: Magagnin Luca , Cojocaru Paula , Dietrich Dagmar , Lampke Thomas
Published: February 2010

In this work, electrodeposition of nickel-single walled carbon nanohorns composite is obtained from a sulfamate bath. Electrodeposition of nickel-nanohorn composites is carried out from a sulfamate bath containing up to 2 g/l of dispersed single walled nanohorns with diameter 30 to 50 nm. Deposits with embedded nanohorns, homogeneously dispersed in metal matrix, are obtained. Structure of the deposits and contents of carbon nanohorns particles in these layers were investigated with respect to the possibility of agglomeration of SWNH particles and bath composition (concentration of SWNH in the electrolyte). Morphology of the coatings and the effects of codeposited particles on metal matrix structure are also reported. Microhardness of the composites has been investigated: Martens hardness is highly influenced by the incorporation of particles.
Preparation of Dendrimer-Like Gold Nanoparticles by Electrochemical Method
Authors: Chiu Pin-Hsiang , Huang Chien-Jung , Yang Cheng-Fu , Meen Teen-Hang , Wang Yeong-Her
Published: February 2010

In this article, we demonstrate the synthesis of dendrimer-like gold nanoparticles (DGNs) by an electrochemical method using micelle templates formed by two surfactants with various amounts of toluene solvent, the primary surfactant being hexadecyltrimethylammonium bromide (CTAB) and the cosurfactant being tetradodecylammonium bromide (TTAB). To investigate the influence of toluene solvent on the DGNs, the amount of toluene was varied in the range from 10 to 50 μL. It was found that the shape of particles was changed from sphere to dendrimer-like shape, and the UV-vis optical absorption measurement revealed a pronounced red shift of the surface plasmon resonance (SPR) peak from 526 to 548 nm.
Electrochemical and Microstructural Studies in Reinforced Mortar, Modified with Core-Shell Micelles
Authors: Koleva Dessi , Van Breugel Klaas , Boshkov Nikolai , Mol J.M.C. , De Wit Hans
Published: February 2010

This work reports on monitoring chloride-induced corrosion in reinforced mortar specimens, with and without addition of polymeric nano-aggregates in the mortar mixture. The investigation is a novel approach to control steel corrosion in reinforced concrete, hereby reporting the preliminary results, related to one of the main objectives: studying the influence of admixed polymer nano-aggregates (in the form of PEO113-b-PS218 core-shell micelles with a very low concentration of 0.006 wt.% per mortar weight) on the corrosion behavior of the steel reinforcement, compared to reference, micelles-free mixtures
Photo-Electrochemical Reduction of Carbon Dioxide on the Self-organized TiO2 Nanotube Layers
Authors: Lin C. C. , Liu S. K. , Chen Y. S. , Li H. F. , Lin Jing Chie , Lee S. L. , Lerondel G. , Chen Yi-Fu
Published: February 2010

Photo-electrochemical reduction of carbon dioxide on the porous films dispersed with self-organized TiO2 nanotubes has been investigated in this work. The porous films were prepared by anodizing a titanium sheet in the electrolyte containing fluoride. Post annealing at 450 oC for 1 h, the crystal of the film turned from amorphous to anatase. The film was dipped in 1 M nitrate solution of Ag(I), Cu(II) and Fe(III), respectively, dried and irradiated by UV-light to load different impurity. Electrochemical tests including cyclic voltammetry (CV), potentiostatic reduction and electrochemical impedance spectroscopy (EIS) were conducted to estimate the catalytic activity of the films. The catalytic activity is higher for the films after compared with the as-anodized films. The catalytic activity of the porous film was enhanced with loading different impurities. The activity increases in the order: load-free < Ag-loaded < Cu-loaded < Fe-loaded films.
One-Step Electrodeposited Cu-In-Ga Thin Films and Cu(In,Ga)Se2 Absorber Synthesis for Solar Cells
Authors: Ribeaucourt Lydie , Chassaing Elisabeth , Savidand Grégory , Lincot Daniel
Published: February 2010

Cu-In-Ga electrodeposition on Mo substrate is carried out in acidic aqueous media. Subsequent selenization leads to Cu(In,Ga)Se2 absorber for thin film solar cells. First, conditions to achieve one-step Cu-In-Ga electrodeposition are analysed. Then, Cu-In and Cu-Ga systems are studied. Cu-In electrodeposition is realized under diffusion-control conditions. For Cu-Ga system, first Cu(II) diffusion-controlled reduction occurs, followed by kinetic under-potential deposition (UPD) of Ga, leading to the formation of CuGa2 compound. Finally Cu-In-Ga electrodeposition is investigated. For Cu-In-Ga system, CuGa2 compound is not noticed, Ga-O codeposition is favored. In presence of citrate, Ga metal is deposited without oxide. Cu(II) and In(III) reductions are both diffusion-controlled, and Ga(III) kinetically controlled, allowing composition control at fixed pH and potential, but with dendritic growth. After selenization, complete Ga insertion is noticed in the formed chalcopyrite absorber. Solar cells with 4% efficiency were achieved despite porous morphology of the absorber.
Corrosion Resistance, Morphological and Electrical Properties of Electroless Ni-Mo-P Thin Films Deposited on Ceramic and Kapton Substrates
Authors: Reyes-Tolosa Maria D. , Kalu Egwu E. , Orozco-Messana Javier , Erb Anna , Kalu Peter , Hernàndez-Fenollosa Maria Angeles , Bolink Henk J.
Published: February 2010

Reduction in the production costs and improved solar cell performance are the main factors driving current research and development efforts in the solar cell field. On this field thin film techniques offer good prospective advantages. All such films require a deposition method for the back contact (BC). Irrespective of the deposition method employed for the absorber layer, the BC on the ceramic is expected to show high corrosion and mechanical stability, prevent diffusion from the substrate into the absorber, and show high optical reflectance and electronic conductivity properties. A low-cost chemical (electroless) deposition technique was used to deposit Ni-Mo-P thin films on Kapton and porcelain ceramic substrates. We will present results on the SEM, XRD and EDAX analysis and characterize the thin film deposits on their corrosion resistance and morphology. The influence of the substrate/Ni-Mo-P interaction on electrochemically deposited ZnO will also be presented.
Direct Cu-on-Ta Electroplating from Ionic Liquids in High Vacuum
Authors: Schaltin Stijn , Shkurankov Andrey , Binnemans Koen , Fransaer Jan
Published: February 2010

Smooth layers of 20 nm of copper have been deposited on a tantalum substrate from ionic liquids under high vacuum conditions. By electrochemical vacuum deposition (EVD) it is possible to achieve extremely low concentrations of oxygen and water, so that the tantalum electrode does not oxidize. Due to the low vapor pressure of ionic liquids, no evaporation of the electrolyte was observed in vacuum. The wide electrochemical windows of the ionic liquids are advantageous to obtain nucleation densities up to 8 1014 m-2 of copper on the tantalum electrode by applying a very large overpotential. Copper was deposited at potentials as negative as -3 V versus a Cu pseudo-reference electrode.
Semiconductor Hybrid Structure: Nanowires Embedded in a Matrix from the Same Material
Authors: Sima Marian , Vasile Eugeniu , Sima Marian , Matei Elena
Published: February 2010

Hybrid systems obtained by incorporation of a nanostructurated material into a matrix from the same thermoelectric (TE) material are predicted to show an increased TE efficiency compared to classical bulk materials. The authors have synthesized Bi1.95Te2.7Se0.35 submicron wires by electrodeposition into a polycarbonate membrane; after polymer membrane dissolution, the wire array supported on a metallic film was electrochemically embedded in a Bi2Te2.65Se0.35 film in order to prepare a hybrid structure. Wires and hybrid structure were analyzed by scanning electron microscopy (SEM), energy X-ray spectrometry (EDX) and X-ray diffraction (XRD).
Growth and Characterization of ZnO:Mn Submicron Wires via Electrodeposition from Nitrate-Lactic Acid Solution
Authors: Sima Marian , Grecu Maria Nicoleta , Sima Marian , Enculescu Ionut
Published: February 2010

Electrodeposition of manganese doped ZnO wires into polycarbonate membranes from an aqueous solution containing Zn(NO3)2, Mn(NO3)2 and lactic acid was investigated using linear sweep voltammetry and electrochemical impedance spectroscopy (EIS). The equivalent electrical circuits used for fitting experimental results were similar to those for characterization of metal/polymer coating systems. The precipitation of metal oxides in the pores of membrane used as template was observed at potentials between -0.9 and -1.15V/SCE. Morphology of the ZnO:Mn submicron wires arrays was observed by scanning electron microscopy and the Mn content of the obtained samples was measured by X-ray analysis. The submicron wires prepared at a potential of -1.1V/SCE have a composition expressed by the formula Zn0.97Mn0.03.
Electrodeposition of Copper in Trenches From a Citrate Plating Bath
Authors: Lizama Tzec Francisco I. , Oskam Gerko
Published: February 2010

A copper - citrate plating bath is investigated for the electro-deposition of copper into trenches with a depth and width of 500 nm. Speciation diagrams representing the copper - citrate complexation characteristics as a function of pH show that a variety of copper - citrate complexes are formed, which is expected to affect the deposition characteristics. Copper was electro-deposited from plating baths at four different pH values, and the deposits in trenches were studied with electron microscopy. The results show that the plating bath at pH 3.1 is capable of adequately filling these structures.
Electrografting of Organic Monolayers on Planar and Nanowire Silicon Substrates
Authors: Vegunta Sri S. , Ngunjiri Johnpeter N. , Xu Wanli , Flake John C.
Published: February 2010

Direct Si-C functionalization of silicon surfaces via electrografting is used to create passive or reactive monolayers on the surface. Cathodic electrochemical grafting of phenyl acetylene (passive) and hexynoic acid (reactive) monolayers on (100) silicon is previously reported. The surface chemistry of the grafted monolayers is analyzed by atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) techniques. Versatile applications of the grafted monolayers in the fields of resists for selective copper electrodeposition, protein immobilization and impedance based biosensors are demonstrated.
Electrodeposition of Te and Cu Thin Films on Boron Doped Diamond (BDD) Electrode
Authors: Fernandes Valéria C. , Matsushima Jorge T. , Baldan Mauricio R. , Azevedo Adriana F. , Linardi Marcelo , Ferreira NeidenÊi G.
Published: February 2010

In this paper boron-doped diamond (BDD) electrodes were prepared by hot filament chemical vapor deposition (CVD) technique using the standard mixture of H2/CH4.The boron doping was obtained from H2 forced to pass through a bubbler containing B2O3 dissolved in CH3OH. BDD quality and morphology were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The electrodeposition of Cu, Te and Cu-Te thin films on BDD electrodes was investigated. Thin films of these metals were deposited potentiostatically from an unstirred, deaerated aqueous solution on BDD and the deposits morphologies were characterized by SEM. Cyclic voltammetry was used to evaluate the electrochemical behavior of BDD electrodes in the deposition and dissolution processes of the Cu, Te and Cu-Te thin films.
Overview of Corrosion Protection with Volatile Corrosion Inhibitors
Authors: Granath Johan
Published: February 2010

Can volatile corrosion inhibitors (VCIs) be used to protect from electronic corrosion? VCIs can efficiently protect a variety of items from environmental attack. VCIs are a class of corrosion inhibiting compounds with a finite vapor pressure. The chemicals are delivered through space by the VCI vapor condensing on the surface of a metal and creating a protective film. VCIs are one of the common methods used for the corrosion protection of metal parts and equipment during manufacturing, storage, shipping and application. The corrosion protection technology with VCIs depends on the following conditions: the material; complexity and size of the equipment, the composition; temperature and humidity of the environment, the manufacturing technology, the storage; transportation and application and the required service life and service life and surface quality of the equipment.
Magnetic Field Effect on Molybdenium Based Alloys Electrodeposition
Authors: Aaboubi Omar , Chopart Jean Paul
Published: February 2010

Preliminary results obtained during the electrodeposition of Cobalt-Molybdenum (CoMo) and Cobalt-Molybdenium-Nickel (CoMoNi) alloys in the presence of a homogeneous magnetic field for various orientations in regards of the working electrode surface plan are reported. The stationary current-potential curves and electrochemical impedance spectroscopy (EIS) measurements show that for the binary CoMo alloys the magnetic field effect was observed only in a restricted potential region. For the ternary CoMoNi the electrolysis current and the EIS responses are strongly modified by magnetic field in the whole range cathodic potential. For a horizontal working electrode maintained at a constant potential typical evolution of the stationary current I ∝B1/3, has been obtained.
CO2 Detection in Nanostructured CoSb2O6 Prepared by a Non-aqueous Colloidal Method
Authors: Michel Carlos R. , Martínez-Preciado Alma H. , Morán-Lázaro Juan P. , Guillén-Bonilla Héctor
Published: February 2010

Gas sensor materials have played a relevant role in the detection and monitoring of pollutant and toxic gases. Carbon dioxide gas sensors are of particular relevance, because the global warming is mainly caused by emission of CO2 to the atmosphere. In that sense, the research of inorganic materials that can detect small amounts of this gas, have attracted the interest of many laboratories worldwide. On the other hand, it is well known that cobalt oxides have interesting catalytical and gas sensing properties. Therefore, in this work, the synthesis and CO2 gas sensing properties of nanostructured CoSb2O6 were explored.
The Grain Size Influence on Boron Doped Diamond Sensitivity for Nitrate Electrochemical Reduction
Authors: Matsushima Jorge T. , Azevedo Adriana F. , Baldan Mauricio R. , Ferreira NeidenÊi G.
Published: February 2010

The grain size influence on boron doped diamond (BDD) sensitivity for nitrate electrochemical reduction was analyzed for films grown at different growth times. Scanning electron and atomic force microscopy analyses showed that the BDD film grown at longer times has larger grain size and higher surface roughness. The grain size effect on BDD sensitivity for nitrate reduction was analyzed by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurements carried out in solutions with and without nitrate ions. BDD films grown at 10 h showed highest sensitivity for nitrate reduction, which is associated to the grain size increase that favors a decrease of the sp2 bonded carbon amount at its grain boundary that turning BDD surface more stable to oxidation process.
Antireflective Subwavelength Structures on 4H-SiC for UV Photodetectors
Authors: Hirabayashi Yasuo , Kaneko Satoru , Akiyama Kensuke , Sakurazawa Keitaro , Yasui Manabu
Published: February 2010

We report for fabricating moth-eye antireflection gratings on silicon carbide substrates using a silica mask inverted from hydrogen silsesquioxane (HSQ) technique. We demonstrate optical properties of subwavelength structure on 4H-SiC. The micro-cone array is fabricated by an ECR-reactive ion etching using Cl2-O2 plasma. A nano-pillar array of silica, formed by an electron-beam lithography using HSQ negative-tone resist and annealing process, is used as the etching mask. The fabricated cone array has a period of 140nm and a height of 177nm. Measured reflectivity of the antireflection structured surface is below 2% at 330nm and 10% at 500nm for incident angle of 20 degree. The specular reflection is slightly affected by varying the angle of incidence up to 80o of s- and p- polarized light at 350nm.