bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatal injury in tree felling and related activities, Victoria, Australia 1992–2007
Authors: Brodie Lisa Ruth , Ibrahim Joseph Elias
Published: February 2010

This study aims to examine fatalities resulting from tree felling and related activities in Victoria, Australia, involving work and do-it-yourself (DIY) activities, 1992–2007. Case identification was undertaken using coronial databases. A manual review of coroners' findings of closed cases was performed. Data collected and examined comprised demographics, occupation, incident location, activity, equipment used, injury mechanism and cause of death. Sixty-two cases were identified during the 16-year period; over 50% comprised DIY deaths (n=33). All but one victim was male. The median age for paid workers was less than for DIY (43 years vs 59 years). One-third of work activities were performed by persons outside professional tree-felling industries. While commercial forestry and logging industries experience a high fatality rate in Australia, non-professionals are also vulnerable to tree-felling injury. Study findings identified in excess of 70% of fatal incidents involved persons not employed within a relevant industry. Prevention efforts must focus on safety beyond workplaces and certain industries alone to reduce these deaths.
Specific density and caloric value of the trunk wood of white birch, black cherry, and sugar maple and their relation to forest succession
Authors: Smith D. W. , Tumey P. R.
Published: February 2010

Studies in the specific density and caloric level per unit volume of trunk wood of three deciduous tree species of differing successional positions support the thesis that tree wood properties are related to the differing successional positions of trees. White birch, (Betulapapyrifera Marsh.), black cherry (Prunusserotina Ehrh.), and sugar maple (Acersaccharum Marsh.) were chosen as being characteristic of early, middle and late stages in forest succession. Wood cores were taken for these species from three different stands in southern Ontario and specific density, calorie value, and caloric level per unit volume were determined.Sugar maple had a higher specific density and caloric value than black cherry or white birch but only small differences were evident between black cherry and white birch. Specific density was found to be the least variable measure, but caloric level per unit volume was also useful, although less accurate. These latter estimates proved to be indicative of the successional positions of the three species.
Some physiological and morphological responses of Quercusmacrocarpa seedlings to flooding
Authors: Tang Z. C. , Kozlowski T. T.
Published: February 2010

Flooding for 30 days induced several changes in Quercusmacrocarpa Michx. seedlings, with stomatal closure among the earliest responses. Stomata remained more closed in flooded than in unflooded plants during the entire experimental period. Leaf water potential was consistently higher in flooded than in unflooded plants. Other responses to flooding included acceleration of ethylene production by stems; formation of hypertrophied lenticels on submerged portions of stems; growth inhibition, with greatest reduction in roots; and formation of a few adventitious roots on submerged portions of the stem above the soil line. Some of the morphological responses to flooding, especially formation of hypertrophied lenticels, appeared to be associated with increased ethylene production. Quercusmacrocarpa seedlings adapted poorly to flooding as shown by failure of stomata to reopen after an early period of flooding and low capacity for production of adventitious roots. The much greater inhibition of root growth than shoot growth by flooding will reduce drought tolerance after floodwaters recede.
A geometrical tree volume model based on the location of the centre of gravity of the bole
Authors: Forslund Robert R.
Published: February 2010

A tree bole model describing a geometrical form in between a paraboloid and cone "paracone" has been developed. The model is based on empirical evidence that the average centre of gravity of aspen (Populustremuloides Michx.) boles without branches lies at 3/10 of the bole height from its base. Outside bark bole volume, V (cubic decimetres), can therefore be estimated nondestructively from the total height, H (metres), and the diameter outside bark, dK (centimetres), measured at a relative height, K, as follows:[Formula: see text]Based on a sample of 70 aspen stems, this equation estimates individual bole volume from total bole length or height and from a single diameter measurement, either at the 3/10 position or at the breast-height position, as accurately as Smalian's formula using seven diameter measurements. Based on the sample, the 3/10 position should be chosen over breast height wherever breast height lies below 20 or above 60% of the total height. It is important that care be taken in the measurement of the diameter due to the sensitivity of the volume equation to diameter variation. In addition to volume estimation, the paracone model provides a comparison profile around which stem form variation within and among species may be observed.
Including equity in the evaluation of outdoor recreation benefits
Authors: Harou P. A.
Published: February 2010

Previous research has shown that forest recreation activities are characterized by high income level participants. If planners introduce an income distribution dimension in the evaluation of recreation benefits, this inequity could be corrected. A straightforward method of weighting benefits is presented here. The travel cost method is used to derive consumer surplus for a recreational site for two different income categories. The weighting scheme is then applied to the consumer surplus calculations to arrive at revised measures of recreation benefits.
An analysis of the growth of silver maple and eastern cottonwood seedlings exposed to ozone
Authors: Jensen K. F.
Published: February 2010

Silver maple (Acersaccharinum L.) and eastern cottonwood (Populusdeltoides Bartr.) seedlings were treated with either 0.0, 0.1, 0.2, or 0.3 ppm ozone for 12 h/day for up to 60 consecutive days. Six seedlings were harvested from each treatment at 10-day intervals to construct growth curves for leaf area, leaf weight, and stem plus leaf weight. Relative growth parameters were calculated from these curves. Relative growth rate, relative leaf-area growth rate, and relative leaf-weight growth rate declined with an increase in time and ozone concentration. Net assimilation rate declined with time in both species. Specific leaf area and leaf-area ratio had no consistent trends.
Effects of SO2 pollution on nitrogen transformation in some organic soils of northeastern New Brunswick: ammonia volatilization
Authors: Mahendrappa M. K.
Published: February 2010

Ammonia volatilization from organic (raw humus) horizons collected from an area in northern New Brunswick variously affected by SO2 (point source) pollution was studied under laboratory conditions. Samples were treated with urea at the rates of 0, 15, and 30 mg N per jar (0, 150, and 300 kg N ha−1) and incubated in closed dynamic systems for 14 days.The quantity of ammonia volatilized was proportional to the rate of urea application. While the quantities of ammonia given off from samples representing unaffected and moderately affected areas did not differ significantly, they were more than 20 times larger than the quantities volatilized from samples representing severely affected areas. The effect of SO2 pollution on ammonia volatilization was related to the original pH of the organic horizons before incubation. The reduced pH of the soil, owing to SO2 pollution, appeared to affect ammonia volatilization through the inhibitory effect of increased hydrogen ion concentration, and (or) by the ability of the acidic upper soil horizons to trap NH3 released in the lower horizons. The threshold pH at which ammonia volatilization is drastically reduced lies between 3.5 and 4.0.
THE EXISTENCE AND CLASSIFICATION OF SYNCHRONY-BREAKING BIFURCATIONS IN REGULAR HOMOGENEOUS NETWORKS USING LATTICE STRUCTURES
Authors: KAMEI HIROKO
Published: February 2010

For regular homogeneous networks with simple eigenvalues (real or complex), all possible explicit forms of lattices of balanced equivalence relations can be constructed by introducing lattice generators and lattice indices [Kamei, 2009]. Balanced equivalence relations in the lattice correspond to clusters of partially synchronized cells in a network. In this paper, we restrict attention to regular homogeneous networks with simple real eigenvalues, and one-dimensional internal dynamics for each cell. We first show that lattice elements with nonzero indices indicate the existence of codimension-one synchrony-breaking steady-state bifurcations, and furthermore, the positions of such lattice elements give the number of partially synchronized clusters. Using four-cell regular homogeneous networks as an example, we then classify a large number of regular homogeneous networks into a small number of lattice structures, in which networks share an equivalent clustering type. Indeed, some of these networks even share the same generic bifurcation structure. This classification leads us to explore how regular homogeneous networks that share synchrony-breaking bifurcation structure are topologically related.
Making virtual walking real
Authors: Souman Jan L. , Giordano Paolo Robuffo , Frissen Ilja , Luca Alessandro De , Ernst Marc O.
Published: February 2010

For us humans, walking is our most natural way of moving through the world. One of the major challenges in present research on navigation in virtual reality is to enable users to physically walk through virtual environments. Although treadmills, in principle, allow users to walk for extended periods of time through large virtual environments, existing setups largely fail to produce a truly immersive sense of navigation. Partially, this is because of inadequate control of treadmill speed as a function of walking behavior. Here, we present a new control algorithm that allows users to walk naturally on a treadmill, including starting to walk from standstill, stopping, and varying walking speed. The treadmill speed control consists of a feedback loop based on the measured user position relative to a given reference position, plus a feed-forward term based on online estimation of the user's walking velocity. The purpose of this design is to make the treadmill compensate fully for any persistent walker motion, while keeping the accelerations exerted on the user as low as possible.

We evaluated the performance of the algorithm by conducting a behavioral experiment in which we varied its most important parameters. Participants walked at normal walking speed and then, on an auditory cue, abruptly stopped. After being brought back to the center of the treadmill by the control algorithm, they rated how smoothly the treadmill had changed its velocity in response to the change in walking speed. Ratings, in general, were quite high, indicating good control performance. Moreover, ratings clearly depended on the control algorithm parameters that were varied. Ratings were especially affected by the way the treadmill reversed its direction of motion. In conclusion, controlling treadmill speed in such a way that changes in treadmill speed are unobtrusive and do not disturb VR immersiveness is feasible on a normal treadmill with a straightforward control algorithm.
Publications on storage and systems research
Authors: Thomasian Alexander
Published: February 2010

We list journals, conferences, workshops, and web sites dealing with systems research, with emphasis on storage systems. We also discuss related areas such as computer architecture, parallel and distributed systems, performance analysis, databases, operating systems, and software systems. Sources of university and industry publications on storage systems are provided. A list of books dealing with storage systems is provided. The Appendix provides general information on publishing technical papers.
Mesh-based many-core performance under process variations
Authors: Musoll Enric
Published: February 2010

Process variations in advanced nodes introduce significant core-to-core performance differences in single-chip multi-core architectures, leading to a loss in core yield.

Cores in a many-core architecture become non-operational because of the direct effect of process variations or indirectly because of the core-interconnect fabric failing to provide total resilience to faults on the fabric itself.

Therefore, two ways to increase core yield are (a) reduce the clock frequency (so more cores can be clocked), and (b) devise a more robust, fault-tolerant interconnect fabric (so fewer cores become isolated).

This work advocates for reducing the clock frequency as a more cost-effective solution to increase the core yield and the overall throughput performance of mesh-based many-core architectures.
Antimicrobial Activity of Electrochemically Oxidized Silver and Copper
Authors: Djokić Stojan
Published: February 2010

The antimicrobial activity of electrochemically oxidized silver and copper was investigated in this work. The surface oxidation of silver and copper samples was performed in a 2M KOH solution potentiostatically. Electrochemically oxidized silver specimens exhibited antimicrobial activity against Pseudomonas aeruginosa, which was attributed to the presence of silver oxide films at the surface. With non-oxidized silver specimens no antimicrobial activity was found. Both, metallic and electrochemically oxidized copper samples exhibited antimicrobial activity. The antimicrobial activity of copper is a consequence of the release of Cu(II) ions into the tested media. The release of Cu(II) ions may occur either due to the presence of copper oxide at the surface of electrochemically oxidized samples or due to corrosion of copper metal in the tested media.
Redox Potentials of Blood Serum in Patients with Acute Cerebral Pathology
Authors: Khubutiya Mogely , Goldin Mark , Romasenko Maria , Volkov Alexander , Hall Peter , Evseev Anatoly , Levina Olga , Aleschenko Elena , Krylov Vladimir
Published: February 2010

According to B. Nordenstrom's concept, homeostasis is controlled by biologically closed electrical circuits in the organism. Therefore, a wide application of implanted platinum electrodes in medicine for diagnostics and treatment is not surprising. Open circuit potentials of platinum electrodes in biological media, termed redox potentials, reflect the level of pro- and antioxidant activities in the organism. The dynamics of redox shifts towards negative potentials in patients with acute cerebral pathology as a result of the treatment by hyperbaric oxygenation was investigated. It was suggested that an increase in antioxidant activity occurs. Thus, redox potential measurements can be used to elucidate certain mechanisms of the effect of hyperbaric oxygenation procedure in patients with acute cerebral pathology. Correlation between redox values and toxicity or quantity of "middle molecule" was found.
Single Walled Carbon Nanotubes (SWCNTs)/Gold Nanoparticles (AuNps) Nanocomposites for Enhancing Electrochemical Response to Detect Neurotransmitters
Authors: Calò Silvia , Curulli Antonella , Zane Daniela , Caschera Daniela , Ingo Gabriel M. , Padeletti Giuseppina
Published: February 2010

Metal nanoparticles/carbon nanotube hybrid materials have attracted attention because of their promising applications in nanoelectronics as well as highly sensitive sensors. It is well known that different metal nanoparticles have been coated or deposited on the side wall of carbon nanotube and on this basis, in this study, we have explored a new strategy to deposit nanoparticles on side wall of Single Walled Carbon Nanotubes (SWCNTs) by one step reaction in aqueous solutions, where gold nanoparticles could be self-coated on carbon nanotubes during their synthesis processes, using citrate reduction as method for the synthesis of gold nanoparticles.
Laws Of Chloride - Ions Oxidation On Various Electrodes and "Green" Electrochemical Method of Higher α-Olefins Processing
Authors: Budnikova Yulia H. , Krasnov Sergei A. , Magdeev Ildar M. , Sinyashin Oleg G.
Published: February 2010

Oxidation of chloride-ions and chlorine gas on different electrodes was studied. The Cl- oxidation potential increases as follows: ERuO2/TiO2<EPt<EGC. The results obtained supplement present concepts on electrochemical behaviour of chloride-ions and reveal substantial differences in proceeding electrochlorination processes on electrodes of different nature. Electrochlorination of higher α-olefins on platinum (Pt) and RuO2/TiO2 (DSA) anodes was shown to proceed as substitutive chlorination to give chloroparaffins containing up to 50% of chlorine, while on glassy carbon (GC) electrodes an additive chlorination (up to 25% of chlorine) occurs.
n-ZnO/p-Si Photodiodes with Improved Photoresponsivities and Acceptance Angles for Solar Applications
Authors: Chen Cheng-Pin , Lin Pei-Hsuan , Chen Liang-Yi , Ke Min-Yung , Cheng Yun-Wei , Huang JianJang
Published: February 2010

We fabricated the n-ZnO/p-Si photodiode and discuss the potential for solar application. By applying the nanostructure of silica nanoparticles above the n-ZnO layer, we observed the enhancement of photoresponsivity and acceptance angle at the wavelength between 400 and 650 nm. The enhancement of photoresponsivity over the conventional device was achieved 17.6% and is due to the improved optical transmission toward the semiconductor through the silica nanoparticles. Furthermore, dramatically increasing of acceptance angle of the nanoparticle coated device was observed, which is attributed to the effect of Bragg diffraction.
Evaluation of Multi-Crystalline Silicon Substrates for Solar Cells by Raman Spectroscopy
Authors: Tachibana Tomihisa , Masuda Junichi , Ogura Atsushi , Ohshita Yoshio , Arafune Koji
Published: February 2010

We evaluated the stress distribution in a multi-crystalline silicon substrate. Two substrates grown by casting method were used. Raman spectroscopy showed that stress was concentrated at grain boundaries. In addition, after annealing, the stress concentration at the grain boundaries disappeared. The difference in the structure of grain boundaries before and after the stress disappeared was analyzed by transmission electron microscopy (TEM) observation. The structure of grain boundaries after annealing was simpler than that without annealing. This might be caused by atomic rearrangement during the annealing process. After annealing process, it was also obtained the changes of distribution of impurities. The stress distribution, annealing process, and the existence of impurities were interacted at grain boundaries.
In-Situ Electrical Measurements of Thin Photovoltaic Silicon Wafers during Nanoindentation
Authors: Kulshreshtha Prashant K. , Youssef Khaled , Rozgonyi George , Stromberg Ryan J. , Nay Richard
Published: February 2010

In this study, we have used a single nanoindentation probe to simultaneously examine the deformation behavior and electrical properties of both mono- and multi-crystalline PV silicon. During nanoindentation loading and unloading cycles, various pressure induced phase transformations occur both under and in the vicinity of the indentation tip. These phase transformations can be monitored in-situ via signature "pop-in" and "pop-out" events that occur in both electrical I-V and physical indent displacement curves. These events are a function of the Si chemistry, structure, and orientation, which we have examined via simultaneous measurements through a conductive nanoprobe, along with complementary spectroscopic Raman analysis.
Amorphization during Fracture of Thin Photovoltaic Silicon Wafers
Authors: Youssef Khaled , Kulshreshtha Prashant K. , Rozgonyi George
Published: February 2010

Nanoindentation was used to stimulate and measure materials processes which occur during the initiation and propagation of micro-crack defects in monocrystalline (100) Si wafers. Silicon amorphization occurs and is accompanied by a monotonic drop in hardness and elastic modulus as the nanoindents approach the micro-crack shank or tip. Identification and profiling of localized phase transitions were obtained in the vicinity of a micro-crack using electron back-scattered diffraction (EBSD) and Raman spectroscopy and indicate that regions of amorphous Si extend for about 10 µm at the edges and ahead of a moving crack tip.
Electrodeposition of Group-IIIA Doped ZnO as a Transparent Conductive Oxide
Authors: Han Xiaofei , Han Kunhee , Tao M.
Published: February 2010

Electrodeposition of Group-IIIA (Al and Ga) doped ZnO with resistivity as low as 3.8×10-4 Ω-cm is reported here. This ZnO can be used as an "on-top" transparent conductive oxide which is deposited on semiconductors in thin-film solar cells such as amorphous Si, CIGS, and organic cells. In addition to low cost, high throughput, and large-area processing, electrodeposition provides advantages other solution-based deposition techniques do not offer, including precise and in-line control of the film thickness. After post-deposition annealing, Al-doped ZnO achieves a resistivity of 8×10-4 Ω-cm and Ga-doped ZnO 3.8×10-4 Ω-cm, respectively. The doping mechanism is believed to be co-precipitation of ZnO with Al2O3 or Ga2O3 in the aqueous solution, leading to Al or Ga substitution of Zn in the ZnO lattice as n-type dopant. Both Al-doped and Ga-doped ZnO shows high transmittance above 80% for films of ~450 nm thick.
A Comparative Study of α- and β-Li3FeF6: Structure and Electrochemical Behavior
Authors: Gonzalo Elena , Kuhn Alois , Garcia-Alvarado Flaviano
Published: February 2010

Two new cathode materials in the Li-Fe-F system are presented: α- and β-Li3FeF6. Both of them are related to the cryolite-type structure. Though the as prepared materials do no intercalate lithium reversibly, decreasing of particle size by mechanical milling in the presence of carbon activate them. Performances of α- Li3FeF6 are better since the synthesis procedure yields particles with smaller size and processing time can be reduced. For example, a fully reversible behavior involving ca. 0.45 Li/formula can be obtained using 5 h of milling for α-Li3FeF6 while for β-Li3FeF6 the same processing produces a material that exhibits a capacity corresponding to 0.12 Li/formula. For 12 h of milling capacity increases notably reaching 100 mAh g-1 (0.7 Li/formula) in the case of the α polymorph. Interestingly, the α-polymorph can be prepared at near room temperature. The easy and cheap synthesis of α-Li3FeF6 makes this material a very promising electrode material.
A New Approach to Prepare Nanosized Cathode Materials
Authors: Kosova Nina , Devyatkina Evgeniya
Published: February 2010

Nanosized LiCoO2 and LiMn2O4 were prepared by preliminary mechanical activation of the mixtures of Li2CO3 with Co3O4 and Li2CO3 with MnO or MnO2 in the presence of carbon in high-energy planetary mill and annealed at 750-800{degree sign}C in air. Added carbon inhibits the particles' interaction during mechanical activation and their growth during annealing. The final products are free from carbon due to its oxidation and evaporation. They are characterized by the domain structure and show high specific discharge capacity and good cycleability.
Biofunctionalization of Nanoelectrode Ensembles: Protection of the Nanoelectrodes with Self-assembled Monolayers
Authors: Silvestrini Morena , Bortolozzo Katia , Paladin Dino , Ugo Paolo
Published: February 2010

In this work we study the possibility to use self-assembled monolayers (SAMs) of thiols to protect the surface of nanoelectrodes ensembles (NEEs) from the undesired adsorption of biomolecules, in particular, proteins. Thioctic acid (TA) and 2-mercaptoethanesulfonic acid (MES) were chosen for this aim. The behaviour of SAM-modified NEEs was studied by cyclic voltammetry as a function of the solution pH using ferrocenecarboxylate as anionic redox probe (FcCOO-) and (ferrocenylmethyl) trimethylammonium (FA+) as cationic redox probe. It was observed that, when the SAM is negatively charged it repels the negative redox probes from the surface of the nanoelectrodes, while the voltammetry of FA+ remain unchanged. The possible protective role of the SAM was confirmed by studying the voltammetric signals recorded with NEEs dipped in a solution of a high adsorbable protein, namely casein, comparing signals recorded at bare NEEs vs. signals at SAM-modified NEEs, in different experimental conditions.
Development of Electro-Catalysts for the Alcohol Oxidation in Anion Exchange Membrane Direct Alcohol Fuel Cells
Authors: Cremers Carsten , Bayer Domnik , Meier Jan O. , Berenger Sophie , Kintzel Birgit , Joos Martin , Tübke Jens
Published: February 2010

The oxidation of ethanol and ethylene glycol at platinum as model catalyst was investigated in potassium hydroxide solution. Experiments comprised the investigation of formed adsorbates by stripping voltammetry of pre-adsorbed alcohols and the investigation of the bulk oxidation as function of the alcohol bulk concentration by cyclic voltammetry and chronoamperometry. For all measurements online mass spectrometry was used to detect the volatile reaction products. For both alcohols it was found that during stripping experiments only the C1 products are formed. For the bulk oxidation of ethanol the CO2 current efficiency rapidly decreases with increasing ethanol concentration showing hardly any CO2 formation at technical relevant concentrations. Although CO2 current efficiencies also dropped for the ethylene glycol oxidation with increasing concentration,the effect was much less pronounced. CO2 formation was thus also observed at technical relevant ethylene glycol concentrations even after longer times under potentiostatic conditions.
Study of the Borohydride Oxidation Reaction on Gold in Alkaline Medium Using On-Line Mass Spectrometry
Authors: Chatenet Marian , Lima Fabio H. , Ticianelli Edson A.
Published: February 2010

The Direct Borohydride Fuel Cell, a potential high-energy-density portable generator, remains limited by the sluggish borohydride oxidation reaction (BOR) kinetics, the mechanism of which is not completely understood. Nevertheless, one usually admits that gold promotes the complete 8-electron BOR. In the present paper, by coupling on line Mass Spectrometry to electrochemistry (OLEMS), we in situ monitored the H2 yield during BOR experiments on sputtered gold electrodes. Our results show non-negligible H2 generation on Au on the whole BOR potential range (0 - 0.8 V vs. RHE), thus revealing that gold cannot be considered as a faradaic-efficient BOR electrocatalyst. From this fact and knowing gold yields slow BOR kinetics, one may conclude that Au is not an ideal electrocatalyst for DBFC anodes.
Polymeric Membranes for Direct Borohydride Fuel Cells: a Comparative Study
Authors: Santos Diogo M. , Sequeira Cesar A.
Published: February 2010

A laboratory direct sodium borohydride/hydrogen peroxide (NaBH4/H2O2) fuel cell using platinum electrodes is studied at room temperature. Several polymeric ion-exchange membranes are considered as ionic separators for the cell. Cell voltages up to 1.84 V and short-circuit currents of 348 mA cm-2 are reported. In the absence of an electric field, reasonable cell stabilities are attained; in the presence of current, cell voltages drop quickly, limiting the cell operation to shorter duration times. Energy densities and specific capacities estimated for a 1 h-cell operation at 1 V are up to 1632 Wh kg-1 and 1632 Ah kg-1, respectively. A power density of about 96 mW cm-2 at a cell voltage of 0.6 V and at a current density of 160 mA cm-2 is reported for the cell using a Nafion 117 membrane, but these values cannot be sustained for appreciable operation times. The tested membranes are compared in terms of their effect on the performance of the NaBH4/H2O2 fuel cell.
Fundamentals and Applications of Electrophoretic Deposition
Authors: Talbot Jan B.
Published: February 2010

Electrophoretic deposition (EPD) is a technique in which charged particles dispersed in a liquid are deposited onto a conductive substrate under the force of an applied electric field. The fundamentals of the EPD process are discussed along with applications of the deposition of phosphors for high-resolution information displays and light-emitting diodes, zeolites for fabrication of modified electrodes and supported membranes, and single-walled carbon nanotube structures.
Corrosion in Electronics at Device Level
Authors: Jellesen Morten S. , Minzari Daniel , Rathinavelu Umadevi , Mo̸ller Per , Ambat Rajan
Published: February 2010

This work presents device level testing of a lead free soldered electronic device tested with bias on under cyclic humidity conditions in a climatic chamber. Besides severe temperature and humidity during testing some devices were deliberately contaminated before testing. Contaminants investigated are ionic or airborne contaminants likely to be introduced by production or service conditions. The effect of changes in processing parameters as a result of production shift to lead free solder (e.g. higher soldering temperature) has also been investigated. Analysis have shown that one printed circuit board assembly (PCBA) in the device is more prone to corrosion reliability and this was further analysed using thermography to detect areas that have high risk of condensation due to lower temperature under working condition. Tested PCBAs are subjected to detailed investigation before and after testing using high resolution photography, detailed optical microscopy and SEM/EDS.
Pulsed Electrosynthesis of Polypyrrole in N-Butyl-N-Methyl- Pyrrolidinium Bis(Trifluoromethanesulfonyl)Imide Ionic Liquid for Electrochemical Sensors
Authors: Zane Daniela , Bianchini Chiara , Appetecchi Giovanni B. , Curulli Antonella , Passerini Stefano
Published: February 2010

Polypyrrole (pPy) thin films were synthesized electrochemically by a pulse method on platinum electrodes in N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (PYR14TFSI). The pulse deposition method allowed the synthesis of well adherent pPy layers on Pt that are attractive for the realization of sensors and biosensors because of their good selectivity with respect to the most common interferents. The EIS (Electrochemical Impedance Spectroscopy) response to hydrogen peroxide and biological interferents indicated pPy as a highly sensitive electrochemical platform for the impedimetric sensing of H2O2. The polymer was overoxidated (opPy) before the characterization to prevent its electrochemical contribution when working in aqueous solution. opPy was then functionalized by glucose oxidase enzyme and the device so assembled was tested as a impedimetric biosensor. This technique showed to have great chances to substitute classic detection methods.
The Mechanism of Impedance-based Gas Sensing with Cr2O3 Thin Film Electrodes at Na-Zeolites
Authors: Dubbe Andreas
Published: February 2010

The mechanism of the impedance response of sodium ion conducting zeolite (Na-ZSM-5) in contact with a Cr2O3 thin film to hydrocarbon gases is studied, using impedance spectroscopy as a function of the applied bias voltage and the film thickness. An ion insertion mechanism of Na+ into the Cr2O3 lattice is proposed. The voltage dependence of the ion insertion resistance is the main cause for the impedance response. In the gas sensor, the potential change is caused by the potentiometric response of the interface between zeolite and electrode to hydrocarbon gases.
Corrosion Resistance of Pulse Zinc Coatings
Authors: Zemanová Matilda , Cocural Marie
Published: February 2010

Zinc coatings prepared from acidic and alkaline commercial electrolytes and electrolytes without additives by direct current and pulse current electrodeposition were studied. Morphology of the formed coatings was analysed by SEM and corrosion properties of the samples by potentiodynamic polarization in a medium containing chloride ions. It was found out that coatings from acidic electrolytes and deposited by direct current and periodic reverse current at frequency of 50Hz provide comparable corrosion properties.
Silane Film Obtained by Sol Gel Process with Cerium Addition for Post-Treatment on Zinc-Talc Composite Coatings
Authors: Vallerius da Costa Marlla , Oliveira Cláudia , Dalla Corte Daniel A. , Rieder S. , Müller Iduvirges , De Fraga Malfatti Célia
Published: February 2010

The electrochemical behavior of zinc-talc composite coatings with and without silane film post-treatment was studied and compared. The composite coatings were obtained by electrodeposition of zinc with talc particles incorporation into the metallic matrix. The xerogel films were obtained by a dip-coating technique from the sol with addition of cerium salts. The electrochemical characterization was carried out by EIS tests and OCP measurement along the immersion time. The morphology of the coatings was evaluated by SEM. The EIS results showed different corrosion phenomena after treatment with silane film. Resistance related to the presence of the silane film (Rsi), and the formation of a corrosion product of cerium/zinc (Rzco) acted jointly to protect the zinc coating, inserting a resistance to the corrosion, which sum it was denominated Rt.
Silane Film Obtained from a Sol Constituted with TMSPMA and TEOS and the Hexavalent Chromate Conversion Film: The Comparative Performance as a Post-Treatment of Zinc Coating
Authors: Vallerius da Costa Marlla , Menezes Tiago L. , Dalla Corte Daniel A. , Oliveira Cláudia , De Fraga Malfatti Célia , Müller Iduvirges
Published: February 2010

Silane films obtained by sol-gel process have been proposed as an alternative to replacement for chromate post-treatment of zinc coatings. The aim of this work was to study the electrochemical behavior of electrodeposited zinc coatings post-treated with silane-cerium film or Cr(VI) conversion coating. Silane-cerium coatings were obtained by dip-coating from a sol constituted by TMSPMA and TEOS silanes precursors with the addition of cerium salt. Electrochemical impedance spectroscopy (EIS) measurements, allied to potentiostatic polarization curves, demonstrated that the post-treatment of zinc with hexavalent chromate conversion or silane film promoted the increase of polarization resistance (Rp) and the reduction of corrosion current density. However it was verified the superior performance of silane-cerium coatings associated to the effect of silane film resistance (Rsi), and the resistance related to the formation of a corrosion product of zinc and cerium (Rzco).
Oxygen Reduction at Cobalt Phthalocyanine Modified Au(111) Electrodes
Authors: Khanfar Mohammad F. , Morin Sylvie
Published: February 2010

Au(111) substrates were modified with cobalt phthalocyanine (CoPc) monolayers. Formation of the adsorbed layer was confirmed by in situ electrochemical scanning tunneling microscopy (STM) while its electrochemical activity was monitored by cyclic voltammetry (CV). The adsorbed molecules have demonstrated a noticeable electrocatalytic activity toward the reduction of oxygen. Significant changes in the STM features of the adsorbed molecules were observed when the measurements were performed in the presence of ca. 1 atm of oxygen at low overpotentials. The reported features were attributed to changes in the electronic structure of the molecule when it forms an intermediate during oxygen reduction. Geometries of two of the possible intermediates, HOOCoPc and O2CoPc, were optimized by density functional theoretical (DFT) method. Frontier orbitals of the hydroperoxo intermediate have electronic density similar to the STM features reported here, which could support that we are probing a reaction intermediate during the O2 reduction process.
Triode Operation of a Proton Exchange Membrane (PEM) Methanol Electrolyser
Authors: Cloutier Caroline R. , Wilkinson David P.
Published: February 2010

Triode operation was shown to improve the PEM electrolysis of liquid methanol and water in a non-flowing system at ambient conditions in the galvanostatic and potentiostatic mode. A decrease in electrolysis voltage requirements proportional to the current or potential imposed in the auxiliary circuit was observed on carbon and noble metal catalysts. This was only observed when the auxiliary current or potential was in the opposite direction compared to the electrolyser circuit current or potential. Cathode potential measurements were reported in triode operation. It appears that triode operation improved the electro-oxidation through the electrochemical pumping of protons and proton spillover. This improvement could not be explained by intrinsic membrane or solution conductivity enhancements due to greater proton concentrations. The mechanism behind the triode enhancement needs clarifications. Triode operation may lead to electrolysis cost reduction through the use of smaller amounts or no precious metal catalyst while maintaining an adequate performance.
Mesoscopic Transport Effects in Electrocatalytic Reactions
Authors: Seidel Yvonne E. , Jusys Zenonas , Wickman Björn , Kasemo Bengt , Behm R. Jürgen
Published: February 2010

Transport effects may not only influence the rate of electrocatalytic reactions, but also the product distribution. The underlying effects were studied under well-defined reaction and transport conditions, using nanostructured Pt/glassy carbon electrodes, which consist of ordered arrays of electrocatalytically active Pt nanostructures on a planar glassy carbon substrate. The effect of varying the density of the Pt nanostructures or the electrolyte flow rate on the reaction characteristics and product distribution was investigated for apparently simple electrocatalytic reactions such as CO oxidation, methanol oxidation and oxygen reduction. It is shown that reducing the Pt coverage leads to an increase of the relative amount of the reaction intermediates. Similar effects are obtained for increasing the electrolyte flow rate. The results are discussed on a molecular scale in terms of the 'desorption - re-adsorption - reaction' model which we had introduced recently (Y.E. Seidel et al., Faraday Discuss. 140, 167 (2008)).
Theoretical Analysis of the Limiting Diffusion Current at a 'Particulate Rotating Disk Electrode'
Authors: Chaparro Antonio M. , Martín Antonio J. , Daza Loreto
Published: February 2010

A model is presented to calculate the current at a 'particulate rotating disk electrode' (prde), that is a rotating disk electrode which active surface is comprised of particles supported on an inactive substrate. The analytical expressions are obtained for the current under diffusion limiting conditions, including two contributions, one from reaction on the front surface of the particles and the other from the edges of the particles. It is shown that this second contribution is the largest under most typical prde parameters. The expressions show a dependence with hydrodynamic parameters (ω, ν, DO) and with parameters describing interaction of electroactive species on non active areas and diffusion towards the edge of the particles. The model predicts for a prde a non linear dependence of i vs. ω0.5, as a difference with the linearity of continuous rde. However, linearity maintains for a Koutecky-Levich plot (1/i vs. 1/ω0.5). This plot type should be used with prde to determine kinetics parameters (n). Experimental results are shown with platinum particles electrodeposited on glassy carbon disk, that validate the main conclusions of the model.
Two Types of Platinum Dissolution in Acid Media: An Electrochemical Nanogravimetric Study
Authors: Inzelt György , Berkes Balazs , Kriston Ákos
Published: February 2010

Smooth and platinized platinum electrodes in contact with sulfuric acid solutions were studied using electrochemical quartz crystal nanobalance (EQCN) technique at different temperatures. Two types of dissolution processes have been observed. A platinum loss was detected during the reduction of platinum oxide, the extent of which depends on the positive potential limit and the scan rate, and to a lesser extent on the temperature. The platinum dissolution during the electroreduction of oxide is related to the interfacial place exchange of the oxygen and platinum atoms in the oxide region. At elevated temperatures two competitive processes take place at high positive potentials: a dissolution of platinum and platinum oxide formation. These phenomena are of importance regarding the long-term stability of proton exchange fuel cells.
Optimization of Predicted Cell Voltage & Caustic Current Efficiency in a Chlor-Alkali Membrane Cell with Application of Genetic Algorithm
Authors: Shojaikaveh Narjes , Ashrafizadeh Seyed Nezamedin , Mohammadi Fereydoon , Amerighasrodashti Amin
Published: February 2010

This paper presents the development of hybrid neural-genetic algorithm model for the prediction of cell voltage and caustic current efficiency (CCE) versus various operating parameters in a lab scale chlor-alkali membrane cell. Each of six process parameters including anolyte pH (2-5), operating temperature (25-90 oC), electrolyte velocity (1.3-5.9 cm/s), brine concentration (200-300 g/L), current density (1-4 kA/m2), and run time (up to 150 min) were thoroughly studied at four levels for low caustic concentrations (5 g/L). According to the obtained results, the predicted cell voltages and current efficiencies using GA modeling were found to be very close to the measured values with an average deviation of about 2.82% & 1.77% for test validation data, respectively. It was also found that the developed model is not only capable to predict the voltage and current efficiency but also to reflect the impacts of the other process parameters on the same functions.
Effect of Dispersed Ceramic Nanoparticles on Microstructure and Performance of Ag Cathode in Solid-Oxide Fuel Cells
Authors: Endo Yoichi , Sasaki Kazuya , Muranaka Minoru , Suzuki Akihiro , Terai Takayuki
Published: February 2010

The microstructure of Ag thin films can be controlled by dispersing La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) nanoparticles and the Ag-LSGM-composite thin film serves as an excellent low-operating-temperature SOFCs (LT-SOFCs) cathode. Here, we demonstrate that the microstructure of Ag thin films can also be controlled by dispersing ZrO2 nanoparticles. By comparing the Ag-ZrO2-composite thin film cathode (ZrO2-nanoparticles-dispersed Ag) with the Ag-LSGM-composite thin film cathode (LSGM-nanoparticles-dispersed Ag), we show that the electrochemical performance of the Ag thin film cathode is directly related to the grain boundary density in the thin film.
A Thermoelectric Cooling/Heating Knife using Bi2Te3-Based Bulks
Authors: Arakawa Kei , Yamaguchi Shigeo
Published: February 2010

We fabricated a Peltier knife after a point-contact-structure Peltier device. The knife tip temperature reached -12.2°C at 16A. When direction of current, the tip was heated, and reached 174.7°C at 20A. Between 180°C and -20°C, the Peltier knife operation was changed from heating to cooling in 10s and from cooling to heating in 13s. The Peltier knife will be useful in medical treatment and bioelectronics.
The Effect of InAsSb Buffer Layer on the Thermoelectric Properties of MOCVD-Grown InSb Thin Films
Authors: Homma Hideyuki , Nagata Hirotaka , Yamaguchi Shigeo
Published: February 2010

We have studied the thermoelectric properties of InSb thin films. They were prepared by metalorganic chemical vapor deposition on sapphire substrate using InAsSb buffer layer. the thickness of InAsSb buffer layer was changed as 0.9nm, 2.6nm, 5.1nm, 10nm, and 15nm. Electrical properties, thermoelectric properties, and crystalline properties of InSb thin films with a InAsSb buffer were assessed using Hall measurement, Power factor and X-ray diffraction. Using InAsSb buffer of 5.1nm, the mobility of InSb was as high as 10240cm2/Vs and the Power factor of InSb was as high as 3.73×10-4W/mK2.
Electrochemical Deposition of Pt Particles from Hexachloroplatinate(IV) and Tetrachloroplatinate(II) Ion Solutions
Authors: Kawai Megumi , Fukumuro Naoki , Yae Shinji , Matsuda Hitoshi
Published: February 2010

The behavior of Pt electrodeposition on n-Si is different between H2PtCl6 (Pt(IV)) and K2PtCl4 (Pt(II)) aqueous solutions. Immersion of bare n-Si wafers in a Pt(II) solution under an open-circuit condition deposits Pt particles on n-Si, but immersion in the Pt(IV) solution deposits no particles. In the Pt(IV) solution, silicon oxide is produced with holes injected into the Si valence band by the reduction reaction of Pt(IV) to Pt(II). The quantity of electrodeposited Pt on the glassy carbon at +0.10 V vs. SCE in the Pt(IV) solution was smaller than that of the Pt(II) case. Cyclic voltammetry shows that the electeroeposition behavior of Pt in the early stage is influenced by the substrates.
Microstructure, Mechanical Behavior and Catalytic Activity of NiO-ZrO2 Anode Composite
Authors: Brodnikovskyi Iegor , Chedryk Valeryi , Vasyliv Bogdan , Ostash Orest , Vasylyev Oleksandr D.
Published: February 2010

Long-term operation of the solid oxide fuel cell (SOFC) depends strongly on reliability of its components. In the case of SOFCs incorporating Ni-ScCeSZ anodes, hydrogen reduction of Ni results in changes in the chemistry, microstructure and properties of the Ni-ZrO2 anode material. In this work, the influence of microstructure of non-reduced (NiO-ScCeSZ) and reduced (Ni-ScCeSZ) anodes on their strength were studied. It was found considerable deterioration in mechanical behavior of Ni-ScCeSZ anodes after reduction comparing to initial state. Biaxial strength of anode samples decrease from ~100 MPa in air at ambient temperature to ~20 MPa after reduction in hydrogen atmosphere at 600°C. Reduced anode samples were used for studying its catalytic activity for conversion of methane into CO. The degradation of anode structures during reduction decreases its catalytic activity.
Visualization of Two-Phase Flow in DMFC Anode Channel
Authors: Numaguchi Tomoshige , Hirano Shinsuke , Eguchi Y. , Ejiri Eiji
Published: February 2010

The DMFC is one of the most promising candidates for the next-generation power source of small electric appliances because the use of liquid methanol fuel makes the cell easy to handle and also it does not require any auxiliary units such as a reformer and a humidifier. Some issues still remain to be solved, however, one of which is that CO2 bubbles generated by the chemical reactions in the anode cover the electrode surface, obstructing the reactions and causing fuel cell performance to deteriorate. In this study, two-phase flow with CO2 bubbles was visualized in the anode channel and upstream and downstream pressures were also measured with high-accuracy pressure sensors in order to investigate the bubble dynamics mechanism in the anode channel. The results show that a certain phase shift occurred between the periods of the cell output voltage fluctuation and the pressure fluctuation in the high current density region.
Electrical and Magnetic Properties of the Li0.42Na0.36CoO2
Authors: Semenova Anna , Kellerman Dina , Markov Alexey
Published: February 2010

Phase Li0.42Na0.36CoO2 attracting scientific attention as promising thermoelectric material was prepared by solid state method in different atmospheres. To clarify the phase formation process the TG/DTA curves of Li-Na-Co-O system were analyzed in detail. The behavior of magnetic susceptibility is studied at low-temperature region for initial sample and also for thermal-treated samples to investigate the phase stability. The thermal dependences of electrical conductivity, thermopower were measured to estimate thermoelectric properties.