Thermal Induction Plasma Processes for the Synthesis of SOFC Materials

This work demonstrates the potential of two recently developed plasma spray methods to deposit Sr‐doped La‐(Mn,Fe,Co) perovskite (LSM, LSF, LSCF) cathodes, and yttria‐doped zirconia (YSZ) electrolytes as components of solid oxide fuel cells (SOFC). These methods are Thermal Plasma Chemical Vapour Deposition (TPCVD) and Suspension Plasma Spraying (SPS). The microstructure obtained is determined by the method applied. TPCVD results in either globular or columnar coatings which were deposited with growth rates up to 30 μm/min. SPS with a deposition rate in excess of 100 μm/min yields coatings of layered microstructure. The homogeneity of the dopant distribution and the phase purity of YSZ is excellent. Process modifications will be necessary, however, to improve the properties in the case of perovskite coatings.     

Hydrogen permeation through internally oxidized Pd alloys

Hydrogen diffusivity and solubility were determined by electrochemical hydrogen permeation tests in samples of Pd_0.97 Al_0.03 and Pd_0.97 Ce_0.03 in the as received and internally oxidized conditions. Internal oxidization caused the appearance of nanosized oxide precipitates in the Pd matrix. The shape and size of precipitates and also the coherence between the precipitates and the matrix were observed by transmission electron microscopy (TEM). Electrochemical hydrogen permeation tests revealed that the presence of oxides increases the apparent hydrogen solubility, S _app, but decreases the hydrogen diffusivity, D _app. The values of D _app were 2.0 × 10⁻¹¹ m² s⁻¹ for vacuum heat treated Pd_0.97 Al_0.03 alloy and 4.0 × 10⁻¹² m² s⁻¹ for internally oxidized Pd_0.97 Al_0.03 alloy. However, the concentration of trapped hydrogen was 49 mol H.m⁻³ for the Pd_0.97 Al_0.03 alloy in the vacuum heat treated condition and 403 mol H.m⁻³ for the Pd_0.97 Al_0.03 alloy in the internally oxidized condition. Both heat treatments were performed at 1073 K for 24 h. The influence of the nature, size and distribution of the precipitates on the hydrogen permeation parameters are discussed in this paper.     

Ultrafast Thermal Plasma Preparation of Solid Si Films with Potential Application in Photovoltaic Cells: A Parametric Study

An innovative method, namely ultrafast plasma surface melting, is developed to fabricate solid films of silicon with very high rates (150 cm²/min). The method is composed of preparing a suspension of solid particles in a volatile solvent and spreading it on a refractory substrate such as Mo. After solvent evaporation, the resulting porous layer is exposed to the flame tale of inductively coupled RF plasma to sinter and melt the surface particles and to prepare a solid film of silicon. It is shown that by controlling the flow dynamics and heat transfer around the substrate, and managing the kinetic parameters (i.e., exposure time, substrate transport speed, and reaction kinetics) in the reactor, we can produce solid crystalline Si films with the potential applications in photovoltaic cells industry. The results indicate that the optimum formation conditions with a film thickness of 250-700 μm is when the exposure time in the plasma is in the range of 5-12.5 s for a 100 × 50 mm large layer. By combining the Fourier’s law of conduction with the experimental measurements, we obtained an effective heat diffusivity and developed a model to obtain heat diffusion in the porous layer exposed to the plasma. The model further predicts the minimum and maximum exposure time for the substrate in the plasma flame as a function of material properties, the porous layer thickness and of the imposed heat flux.     

Information Retrieval and Categorisation using a Cell Assembly Network

Simulated networks of spiking leaky integrators are used to categorise and for Information Retrieval (IR). Neurons in the network are sparsely connected, learn using Hebbian learning rules, and are simulated in discrete time steps. Our earlier work has used these models to simulate human concept formation and usage, but we were interested in the models applicability to real world problems, so we have done experiments on categorisation and IR. The results of the system show that congresspeople are correctly categorised 89% of the time. The IR systems have 40% average precision on the Time collection, and 28% on the Cranfield 1,400. All scores are comparable to the state of the art results on these tasks.     

Photo-removal of sulfamethoxazole (SMX) by photolytic and photocatalytic processes in a batch reactor under UV-C radiation (λmax=254 nm)

In this study, photolytic and photocatalytic removal of the antibiotic sulfamethoxazole (SMX) under UVC radiation (λ=254 nm) was investigated. The light intensity distribution inside the batch photoreactor was characterized by azoxybenzene actinometry. The intensity of incident radiation was found to be a strong function of position inside the reactor. 12 mg L(-1) of SMX was completely removed within 10 min of irradiation under UVC photolysis, compared to 30 min under TiO(2) photocatalysis. COD measurement was used as an indication of the mineralization efficiency of both processes and higher COD removal with photocatalysis was shown. After 6h of reaction with photolysis and photocatalysis, 24% and 87% removal of COD was observed, respectively. Two of the intermediate photo-products were identified as sulfanilic acid and 3-amino-5-methylisoxazole by direct comparison of the HPLC chromatograms of standards to those of treated solutions. Ecotoxicity of treated and untreated solutions of SMX towards Daphnia magna was also investigated. It was found that a 3:1 ratio of sample to standard freshwater and a high initial concentration of 60 mg L(-1) of SMX were used to obtain reliable and reproducible results. The photo-products formed during photocatalytic and photolytic processes were shown to be generally more toxic than the parent compound.     

Tobacco and ectopic pregnancy. Arguments in favor of a causal relation]

The aim of this paper was to study gender differences in the percept-genetic method Defense Mechanism Test (DMT) among a group of 60 adolescent subjects. Three subgroups were used: patients with psychotic disorders (Axis 1); borderline personality disorder (Axis 2) according to the DSM-IV classification system, and a non-patient group. The test protocols were scored with respect to 124 DMT variables and analyzed by means of the multivariate projection method Partial Least Squares (PLS) in latent structures. The overall results showed considerable gender differences in the whole group as well as in the subgroups. The most striking finding was that girls compared to boys were characterized by the perceptual defense identification with the opposite sex, which means that they perceived male gestalts instead of females in the stimulus picture. When both gender and diagnostic group membership were considered simultaneously, the influence of diagnostic group membership seemed to be stronger than gender even if there was an interaction between diagnoses and gender. It was concluded that gender must be considered when the DMT is used on adolescent populations.     

Construction of composite scales for risk assessment in epidemiology: an application to ectopic pregnancy

Composite scoring systems that combine information contained in a number of risk factors are being used increasingly in clinical practice, planning, and health risk appraisal. The authors propose a methodological framework for the construction and validation of a composite measurement scale to assess the risk, considered as a continuous phenomenon, of developing a particular disease or outcome. This framework integrates several statistical methods, especially those concerning model fitting, coefficient rounding, and validation strategy. It also uses psychometric methods, addressing important measurement properties such as measurement level, content and construct validity, and reliability of the constructed scale. The proposed framework is illustrated by application to the construction of a composite scale for measurement of the risk of ectopic pregnancy.     

In vivo studies on lead content of deciduous teeth superficial enamel of preschool children

The amount of lead in the superficial enamel of deciduous teeth from 4- and 5-year-old children was determined by means of an enamel biopsy followed by lead analysis by graphite furnace atomic absorption spectrometry. Children examined in this study (n=329) attended public preschools in the city of Piracicaba, SP, Brazil. The selection of preschools was based on geographical location: some were located in an industrial area of the city, whereas others were located in an area devoid of industries. The objectives of this study were (1) to test whether enamel biopsies were an appropriate method for lead content population screening in young children; (2) to verify the lead content of superficial enamel of preschool children's deciduous teeth and to compare the results obtained from children exposed to different environments; (3) to analyze how biopsy depth correlated with lead content and affected comparisons between groups. An adhesive tape with a central hole (diameter=1.6 mm) was placed on one of the upper central incisors. Five microliters of 1.6 mol l⁻¹ HCl in 70% glycerol (v/v) were applied to this area for 20 s, followed by a rinse with 5-μl ultrapurified water for 10 s. It was shown that the technique was feasible for population studies on young children. The lead concentration in enamel biopsies from the industrial area children (median: 169 ppm Pb) was significantly higher than that from the children living far from industries (118.1 ppm Pb) (P<0.0001). Analysis of the data showed that biopsies deeper than 3.9 μm gave more reliable results for comparisons between groups. To our knowledge, this study is the first to use an enamel microbiopsy to characterize a large sample of young children in vivo for lead monitoring in teeth.