A three-dimensional heterogeneity analysis of electrochemical energy conversion in SOFC anodes using electron nanotomography and mathematical modeling

In this paper a fully three dimensional, multiphase, micro-scale solid oxide fuel cell anode transport phenomena numerical model is proposed and verified. The Butler-Volmer model was combined with empirical relations for conductivity and diffusivity - notably the Fuller-Shetler-Giddings equation, and the Fickian model for transport of gas reagents. FIB-SEM tomography of a commercial SOFC stack anode was performed and the resulting images were processed to acquire input data. A novel method for estimating local values of Triple Phase Boundary length density for use in a three-phase, three-dimensional numerical mesh was proposed. The model equations are solved using an in-house code and the results were verified by comparison to an analytical solution within the range of its applicability. A limited parametric study was performed to qualitatively assess simulation performance and impact of heterogeneity. Despite the high dependence of the SOFC anode performance on the geometry of its anisotropic, three-phase microstructure there are very few micro-scale numerical models simulating transport phenomena within these electrodes.     

Technological aspects of sunflower biomass and brown coal co-firing

The technological problems occurring in the co-firing of biomass and brown coal (lignite) prompted this research project. During the fuel preparation, accidental self-ignition and explosions were several times reported by power plants operators. The aim of this study was to evaluate brown coal, sunflower husks and sunflower husk pellets as fuels for co-firing in energetic boilers. Sunflower husk had a lower ash content and calorific value than the pellets. The range of the combustion temperatures of the biomass (200–300 °C) was narrower than that of brown coal (200–800 °C). The formation of highly alkaline ash from the biomass resulted in the formation in boiler of agglomerates of ash. The elemental composition, thermogravimetric and biological analyses suggested that the pellets contained synthetic additives difficult to identify. The biological method was proposed for evaluating biomass additives. The use of additional agents in the pelletizing process may influence on the combustion parameters. Mixing biomass with brown coal may occasionally result in self-ignition in the logistic chain. Plastic additives and biological activity may contribute to self-ignition.     

Characterisation of four popular Polish hop cultivars

Polish cultivars of hop (Humulus lupulus L.) are well known as aroma and bitter raw material in the brewing industry. To characterise four popular Polish hop cultivars, Lubelski (Lublin), Marynka, Sybilla and Iunga (also known as Junga), the essential oil profiles were determined by gas chromatography/flame ionisation detector (GC‐FID) and gas chromatography/chemical ionisation mass spectrometry (GC‐CIMS) and the alpha/beta acids amounts by high‐performance liquid chromatography/diode array detector (HPLC‐DAD) analysis. In addition, the multivariate statistical analysis of the volatile profiles was performed. The results obtained evidenced qualitative and quantitative differences between the four cultivars studied and the foreign hops described in the literature. Lubelski and Iunga showed the typical chemical profile of the fine‐aroma and high‐alpha cultivars, respectively. In Marynka and Sybilla, the average amounts of alpha acids were similar to the bitter hops, but with a volatile profile characteristics of the fine‐aroma and aroma cultivars respectively.     

Universal constraints on the sound structure of language: Phonological or acoustic?

Languages are known to exhibit universal restrictions on sound structure. The source of such restrictions, however, is contentious: Do they reflect abstract phonological knowledge, or properties of linguistic experience and auditory perception? We address this question by investigating the restrictions on onset structure. Across languages, onsets of small sonority distances are dispreferred (e.g., lb is dispreferred to bn). Previous research with aural materials demonstrates such preferences modulate the perception of unattested onsets by English speakers: Universally ill-formed onsets are systematically misperceived (e.g., lba → leba) relative to well-formed onsets (e.g., bn). Here, we show that the difficulty to process universally ill-formed onsets extends to printed materials. Auxiliary tests indicate that such difficulties reflect phonological, rather than orthographic knowledge, and regression analyses demonstrate such knowledge goes beyond the statistical properties of the lexicon. These findings suggest that speakers have abstract, possibly universal, phonological knowledge that is general with respect to input modality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of hydrogen on room-temperature plasticity of B2 iron aluminides

Different sensitivities to hydrogen embrittlement for the disordered and ordered B2 FeAl alloys have been investigated. The plasticity of annealed alloys (before hydrogenating) has been found to decrease with increasing the long-range order parameter. An intrinsic weakness of FeAl phase grain boundaries revealed at a high degree of ordering. The results of bending tests on specimens annealed and cathodically charged with hydrogen have shown that the influence of hydrogen on the plasticity diminishes with the increase in the degree of FeAl phase ordering.     

IQ level and performance on the Halstead-Reitan Neuropsychological Test Battery for Older Children.

121 9–14 yr olds were divided into 4 groups based on their WISC-R Full Scale IQ score: (a) 70–79, (b) 80–89, (c) 90–99, and (d) >100. Performance of these 4 groups was compared on the Halstead-Reitan Neuropsychological Test Battery for Children (HRNTBC) using a multiple-levels-of-inference framework: (a) level of performance, (b) pattern of performance, and (c) right–left hand differences. Results indicate a significant influence of IQ on level of performance for 6 of 14 test measures. Tests of problem-solving abilities, language skills and auditory perceptual analysis were most affected, whereas little influence was observed for tests of basic and simple motor functions. Right–left hand differences were also unaffected by IQ level. Results call attention to the importance of considering IQ level in the interpretation of performance on the HRNTBC. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microscopic and electrochemical characterization of lead film electrode applied in adsorptive stripping analysis

Lead film electrodes (PbFEs) deposited in situ on glassy carbon or carbon paste supports have recently found application in adsorptive stripping voltammetric determination of inorganic ions and organic substances. In this work, the PbFE, prepared in ammonia buffer solutions, was investigated using scanning electron microscopy, atomic force microscopy and various voltammetric techniques. The microscopic images of the lead films deposited on the glassy carbon substrate showed a considerable variability in microstructure and compactness of the deposited layer depending on the selected experimental conditions, such as the concentration of Pb(II) species, the nucleation and deposition potential, and the time applied. The catalytic adsorptive systems of cobalt and nickel in a solution containing 0.1 ammonia buffer, 2.5 × 10⁻⁵ M nioxime and 0.25 M NaNO₂ were employed to investigate the electrochemical characteristics and utility of the in situ prepared lead films.The optimal parameters, i.e. the lead concentration in the solution, the procedure of film removal, and the time and potential of lead nucleation and film deposition for the adsorptive determination of metal traces, were selected, resulting in the very good reproducibility (RSD = 4.2% for 35 scans) of recorded signals. The voltammetric utility of the lead film electrode was compared to that of glassy carbon, mercury film and bismuth film electrodes, and was subsequently evaluated as superior.     

The effect of solar radiation on the flavonol content in broccoli inflorescence

The effect of solar radiation on the quercetin and kaempferol contents in the inflorescence of three broccoli cultivars (‘Lord’, ‘Marathon’ and ‘Fiesta’) was investigated from 1999 to 2001. Great differences in the contents of both flavonols, dependent on growing time and cultivar, were found. Quercetin and kaempferol contents varied from 14.3 to 81.0 mg kg⁻¹ f.w. and from 35.9 to 213 mg kg⁻¹ f.w., respectively. Inflorescences of the cultivar ‘Lord’ were characterised by the highest mean content of quercetin and those of cultivar ‘Fiesta’ of kaempferol. The contents of both flavonols were highly positively correlated with total solar radiation in the period from planting to the harvest of broccoli inflorescences.     

Are phonological representations of printed and spoken language isomorphic? Evidence from the restrictions on unattested onsets.

Are the phonological representations of printed and spoken words isomorphic? This question is addressed by investigating the restrictions on onsets. Cross-linguistic research suggests that onsets of rising sonority are preferred to sonority plateaus, which, in turn, are preferred to sonority falls (e.g., bnif, bdif, lbif). Of interest is whether these grammatical preferences constrain the recognition of auditory and printed words by speakers of English--a language in which such onsets are unattested. Five experiments compare phonological lexical decision responses to nonwords, including unattested onsets, through either aural or visual presentation. Results suggest that both hearers and readers are sensitive to the phonotactics of unattested onsets. However, the phonotactic generalizations of hearers and readers differ on their scope and source. Hearers differentiated all three types of onsets (e.g., bnif, bdif, and lbif), and their behavior implicated both grammatical and statistical constraints. In contrast, readers were able to differentiate only those structures similar to attested English onsets from dissimilar structures (i.e., bnif vs. bdif or lbif), and their preferences reflected statistical knowledge alone. These findings suggest that the phonological representations informing lexical decision to spoken and printed words are not isomorphic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)