An analytical study of thermal barrier coated first stage blades in a JT9D engine

Steady state and transient heat transfer and structural calculations were completed to determine the coating and base alloy temperatures and strains. Results indicate potential for increased turbine life using thin durable thermal barrier coatings on turbine airfoils due to a significant reduction in blade average and maximum temperatures, and alloy strain range. An intepretation of the analytical results is compared to the experimental engine test data

Influence of linseed oil on the microstructure and composition of lime and lime-metakaolin pastes after a long curing time

This study investigates the effect of linseed oil on the microstructure of lime and lime-metakaolin pastes after 68 months of curing under controlled conditions. The hydrophobicity imparted by linseed oil to the pastes’ bulk was confirmed by measuring water drops’ contact angle. The results of thermal analysis, X-ray powder diffraction, and Fourier transform infrared spectroscopy showed that linseed oil significantly hindered the carbonation reaction in both lime and lime-metakaolin pastes and promoted the development of amorphous phases. The obtained results also indicated that linseed oil could foster the pozzolanic reaction in the lime-metakaolin system by stabilizing and/or promoting the development of hydration products resulting in reduced shrinkage in comparison with the reference

A model of phonological processing, language, and reading for students with mild intellectual disability

Little is known about the relationships between phonological processing, language, and reading in children with intellectual disability (ID). We examined the structure of phonological processing in 294 school-age children with mild ID and the relationships between its components and expressive and receptive language and reading skills using structural equation modeling. Phonological processing consisted of two distinct but correlated latent abilities: phonological awareness and naming speed. Phonological awareness had strong relationships with expressive and receptive language and reading skills. Naming speed had moderate relationships with these variables. Results suggest that children with ID bring the same skills to the task of learning to read as children with typical development, highlighting the fact that phonologically based reading instruction should be considered a viable approach

Preliminary study of the pozzolanic activity of dumped mine wastes obtained from the North Bohemian basin in the Czech Republic

Three dumped raw materials, a tuff and two bentonites, obtained from two mining sites at the North Bohemian basin in the Czech Republic, have been studied in order to evaluate them as pozzolanic admixtures in lime mortars for employment in restoration of cultural heritage objects. After thermal activation (800 °C; 5 h), their pozzolanic properties were compared with those of commercial metakaolin. Quantitative phase analysis with the Rietveld method from X-ray powder diffraction patterns, morphological observations, as well as the Frattini and the modified Chapelle tests were performed. In addition, lime mortars, incorporating the fired materials, were prepared and subjected to simultaneous thermal analysis after a 28-day initial curing (20 ± 1 °C; 60 ± 5 % RH). The results showed that all three materials possess pozzolanic activity. However, when employed in lime mortars they did not result in formation of pozzolanic reaction products. Two methods were proposed to improve their reactivity; grinding to obtain finer particle size and removal of quartz content where necessary

Synthetic calcium carbonate improves the effectiveness of treatments with nanolime to contrast decay in highly porous limestone

Three synthetized polymorphs of calcium carbonate have been tested in combination with the suspension of nanolime particles as potential consolidating agents for contrasting stone decay and overcome some of the limitations of nanolime agents when applied to substrates with large porosity. The modifications induced in the pore network of the Maastricht limestone were analyzed with microscopy and in a non-invasive fashion with small angle neutron scattering and synchrotron radiation micro-computed tomography. A reduction in porosity and pore accessibility at the micrometric scale was detected with the latter technique, and ascribed to the improved pore-filling capacity of the consolidation agent containing CaCO3 particles. These were found to be effectively bound to the carbonated nanolime, strengthening the pore-matrix microstructure. Penetration depth and positive effect on porosity were found to depend on the particle size and shape. Absence of significant changes in the fractal nature of the pore surface at the nanoscale, was interpreted as indication of the negligible contribution of nanolime-based materials in the consolidation of stones with large porosity. However, the results indicate that in such cases, their effectiveness may be enhanced when used in combination with CaCO3 particles, owing to the synergic effect of chemical/structural compatibility and particle size distribution

Neuroloogilise seisundi varajase halvenemise sagedus pärast trombolüüsi ja seda mõjutavad tegurid: SITS registri andmed

Eesti Arst 2021; 100(4):241 &nbsp