Thermodynamics and kinetics of reactions in protective coating systems

A study of the aluminization of Ni from packs containing various percentages of unalloyed Al confirmed that the surface aluminum content of specimens aluminized tends to decrease with time and consequently a simple parabolic law for the weight-gain vs. time relationship is not obeyed. The diffusivity-composition relationship in NiAl was examined, and a set of curves is presented. A numerical method for the calculation of coating dissolution rates was developed and applied to NiAl-Ni3Al type of coatings

On the kinetics of pack aluminization

A theory of pack aluminization has been formulated by combining gaseous and solid-state diffusion rates. This theory relates the surface composition of the coating and therefore, in principle, the phase morphology and the growth rate of the coating, to pack operating parameters such as pack aluminum density, type of activator, temperature and others. Experimental data on the aluminization of unalloyed nickel in pure aluminum packs obtained to date are in good agreement with the predictions of the theory

Redefining the timing and circumstances of the chicken's introduction to Europe and north-west Africa

This is the final version. Available on open access from Cambridge University Press via the DOI in this recordLittle is known about the early history of the chicken (Gallus gallus domesticus), including the timing and circumstances of its introduction into new cultural environments. To evaluate its spatio-temporal spread across Eurasia and north-west Africa, the authors radiocarbon dated 23 chicken bones from presumed early contexts. Three-quarters returned dates later than those suggested by stratigraphy, indicating the importance of direct dating. The results indicate that chickens did not arrive in Europe until the first millennium BC. Moreover, a consistent time-lag between the introduction of chickens and their consumption by humans suggests that these animals were initially regarded as exotica and only several centuries later recognised as a source of ‘food’.Arts and Humanities Research Council (AHRC)Natural Environment Research Council (NERC)Chair of Palaeoanatomy, LMU Munic

Investigations on cultural and cellulolytic activity in Pyricularia oryzae Cavara

The growth of Pyricularia oryzae Cavara was studied on 2 solid complex media, malt and rice extracts, under different conditions. The 2 culture media encouraged growth of the phytopathogen but their effects varied between strains. Statistical analysis showed that the effect of media on the growth of the different strains was non-significant, while inter-strain differences were due to pH. Growth was better at pH 6 and 7 than at pH 5, and was inhibited below 5 and above 37°C. It was optimum at 28°C, moderate at 23°C and minimum at 15°C, with very low sporulation or without sporulation, depending on strains. Low relative humidity apparently lowered sporulation in all strains. On synthetic media, nitrate-N as growth nutrient was preferred to ammonium-N by P oryzae. A remarkably better development was observed in synthetic medium containing sodium nitrate in place of ammonium salts. Four strains out of 5 were tested for cellulolytic activity. The levels of cellulose degradation were not consistent in Avicel azure and Cellulose azure for all the strains, and showed various degrees of positive activity.Conditions de culture et activité cellulolytique chez Pyricularia oryzae Cavara. La croissance de Pyricularia oryzae Cavara a été étudiée sur 2 milieux solides complexes à base d'extraits de malt et de riz, sous différentes conditions. Ces 2 milieux favorisent le développement du pathogène d'une manière variable selon les souches. L'analyse statistique montre que l'effet du milieu sur la croissance n'est pas significatif alors que les différences entre souches sont dues au pH. La croissance est meilleure à pH 6 et 7 qu'à pH 5 et est inhibée en dessous de 5°C et au-dessus de 37°C. Elle est optimale à 28 °C, modérée à 23°C et minimale à 15°C avec une sporulation faible ou nulle selon les souches. Sur milieu synthétique P oryzae préfère l'azote nitrique à l'azote ammoniacal. Le développement est significativement meilleur lorsque le nitrate de sodium remplace les sels d'ammonium. La recherche de l'activité cellulolytique de 4 souches a montré différents niveaux d'activité sur Avicel azure et Cellulose azure

Idiopathic collapsing focal segmental glomerulosclerosis: A clinicopathologic study

Idiopathic collapsing focal segmental glomerulosclerosis: A clinicopathologic study. A review of all native kidney biopsies at our center from 1974 to 1993 identified 43 cases of idiopathic focal segmental glomerulosclerosis (FSGS) with predominantly collapsing features and lacking evidence of HIV-1 infection or intravenous drug use. No case was identified before 1979 and the incidence of this entity has progressively increased over the past two decades. Compared to 50 age-matched controls of idiopathic FSGS with typical perihilar scars, the group of idiopathic collapsing FSGS displayed black racial predominance, a higher serum creatinine and more severe features of nephrotic syndrome at biopsy. Morphologic features of visceral epithelial cell hypertrophy and hyperplasia, tubular microcysts, tubular epithelial degenerative and regenerative features and interstitial edema were more prevalent and severe in collapsing FSGS. Median time to ESRD was rapid in collapsing FSGS versus controls (13.0 months vs. 62.5 months, P < 0.05). Correlates of progression to ESRD included a higher initial serum creatinine and failure to undergo remission of proteinuria. Both glomerulosclerosis and certain features of tubular damage were independent predictors of the level of renal function at time of biopsy, but not of the rate of progression of renal insufficiency. Although three patients had partial or completespontaneous remissions, none of 26 patients treated with steroids alone responded. Idiopathic collapsing FSGS is a variant of FSGS with increasing incidence, distinct clinicopathologic features, black racial predominance, a rapidly progressive course and relative steroid resistance

On the use of sample entropy to analyze human postural sway data

National audienceno abstrac

On the use of sample entropy to analyze human postural sway data

National audienceno abstrac