We evaluated mechanical properties (first matrix cracking stress, strength, and work-of-fracture) of Nicalon-fiber-reinforced silicon carbide matrix composites with three different fiber lay-up sequences (0"/20"/60", O0/4Oo/6O0, and 0"/45") at various temperatures from room to 1300°C. Up to 1200"C, ultimate strength and work-of-fracture for the 0"/40"/60" and 0"/45" composites increased, but th...

PURPOSE To quantify the changes of hemoglobin mass (Hbmass) and maximum oxygen consumption (VO2max) after 22 days training at 1300-1800 m combined with nightly exposure to 3000-m simulated altitude. We hypothesized that with simulated 3000-m altitude, an adequate beneficial dose could be as little as 10 h/24 h. METHODS Fourteen male collegiate runners were equally divided into 2 groups: altit...

In this paper, the fatigue damage and lifetime of 2D SiC/SiC ceramic-matrix composites (CMCs) under cyclic fatigue loading at 750, 1000, 1100, 1200 and 1300 °C in air and in steam atmosphere have been investigated. The damage evolution versus applied cycles of 2D SiC/SiC composites were analyzed using fatigue hysteresis dissipated energy, fatigue hysteresis modulus, fatigue peak strain and inte...

The densification behavior, microstructure and mechanical properties of bulk TiB₂-based ceramic composites, fabricated using the spark plasma sintering (SPS) technique with elements of (Fe-Ni-Ti-Al) sinter-aid were investigated. Comparing the change of shrinkage displacement of pure TiB₂ and TiB₂-5 wt% (Fe-Ni-Ti-Al), the addition of elements Fe-Ni-Ti-Al into TiB₂ can facilitate sintering of the...

We describe a four-layered model for near infrared light propagation in a human head based on the Monte Carlo method. With the use of three-dimensional voxel-based media discretization, photon migration in the brain is analyzed by both the time-of-flight measurement and the spatial sensitivity profile. In the measurement of brain activity, the selection of light wavelength and the distance betw...

NAH~WOLD, M. L., W. H. HESS AND D. R. BETHELL. ~~~1~~~~~~ and ~at?tjtz(~but~~ri~ acid in ~~Ilt~red cells of nervou.s wirm origin. BRAIN RES. BULL. 5: Suppl. 2,477-483, 1980.-C-1300 neuroblastoma and C-4 astrocytoma cells in culture were utilized as models of y-aminobutyric acid (GABA) metabolism in neurons and glia, respectively. Both cell lines were exposed to 0, 0.7, 1.0, 1.7, or 3.0% halotha...

The microwave sintered zirconia ceramics with 0, 1, 3, and 5 wt% TiO2 addition at a low sintering temperature of 1300°C and a short holding time of 1 hour were investigated. Effect of contents of TiO2 addition on microstructure and mechanical properties of microwave sintered zirconia bioceramics was reported. In the sintered samples, the main phase is monoclinic zirconia (m-ZrO2) phase and mino...

The region of the rubella virus nonstructural open reading frame that contains the papain-like cysteine protease domain and its cleavage site was expressed with a Sindbis virus vector. Cys-1151 has previously been shown to be required for the activity of the protease (L. D. Marr, C.-Y. Wang, and T. K Frey, Virology 198:586-592, 1994). Here we show that His-1272 is also necessary for protease ac...