Sintering Behavior of Nanocrystalline Zirconia Prepared by Chemical Vapor Synthesis

Powder synthesis and ceramic processing methods have to be improved to take full advantages of new, improved properties of nanocrystalline ceramics. Sintered nanocrystalline ceramics of pure, undoped zirconia are formed from nanocrystalline powder of optimized quality obtained by the chemical vapor synthesis (CVS) method. The as-synthesized CVS ZrO₂ powder is nonagglomerated with a crystallite size of about 5 nm, narrow size distribution, and high crystallinity. On uniaxial compaction a transparent green body of ultrafine, uniform microstructure and narrow pore size distribution corresponding to the grain size distribution is formed, which is sintered under vacuum at 950°C into a transparent, fully dense ZrO₂ ceramic with a grain size of 60 nm.     

Slotline Stepped Circular Rings for Low-Loss Microstrip-to-Slotline Transitions

We propose a low-loss slotline (SL) stepped circular ring termination for use in a microstrip-to-slotline (MS-to-SL) transition. Not only does this termination achieve broadband characteristics, but it also reduces SL radiation. The experimental results show that, using the proposed technique, the radiation loss around the pass-band frequency is lower than that of the conventional transitions using radial or circular pad terminations     

Short communication: Fat-soluble vitamin and mineral status of milk replacer-fed dairy calves: Effect of growth rate during the preruminant period

Effects of growth rate on fat-soluble vitamin and macro- and micromineral concentrations in the circulation of preruminant dairy calves were evaluated. Dietary treatments were designed to achieve 3 targeted rates of gain [no growth (NG) = 0.0 kg/d; low growth (LG) = 0.55 kg/d; or high growth (HG) = 1.2 kg/d] over a 7-wk period. Milk replacer (MR) intakes necessary to achieve these growth rates were estimated using the National Research Council's Nutrient Requirements of Dairy Cattle calf model computer program. All of the calves were fed a 30% crude protein, 20% fat MR reconstituted to 14% dry matter. The diets were formulated to ensure that protein was not a limiting nutrient. No-growth and LG calves were supplemented additionally with vitamins A, D, and E to compensate for treatment differences in dry matter intake relative to the HG calves; however, no attempt was made to adjust mineral intake based on MR consumption. Growth rates for NG (0.11 kg/d), LG (0.58 kg/d), and HG (1.16 kg/d) calves differed during the study. Health was minimally affected by growth rate and this was reflected by comparable and relatively low serum haptoglobin concentrations in all calves during the 7-wk period. Concentrations of serum retinol, 25-(OH)-vitamin D₃, and zinc were unaffected by growth rate. The HG calves had lower RRR-α-tocopherol concentrations than NG and LG calves at wk 7, suggesting that the increased growth rate of HG calves was associated with increased utilization of vitamin E. Serum concentrations of all vitamins increased with age. Copper, calcium, and phosphorous concentrations in HG calves exceeded those in LG and NG calves during the latter weeks of the study, likely because of increased MR intake by HG calves. Fat-soluble vitamin and mineral concentrations for all treatment groups remained within ranges considered normal for preruminant calves.     

An unexpected admirer of Ladygina-Kohts.

Previously unknown correspondence between Nadya Nikolaevna Ladygina-Kohts, author of The Chimpanzee Child and the Human Child (1935), and Harry Harlow shows a reciprocal interest in, and admiration for, each other's work. In 1960 and 1961, they exchanged some 9 letters as well as numerous reprints and publications. The correspondence shows that Ladygina-Kohts and Harlow had been following each other's work for years and that Ladygina-Kohts's work may have been one of the major inspirations to Harlow's primate program. (PsycINFO Database Record (c) 2011 APA, all rights reserved)