A total of 270 animals of 5 species was exposed by inhalation to compounds of zirconium for 6 hours per day, 5 days per week. One group of animals was exposed to ZrO{sub 2} at an atmospheric concentration of 75 mg. Zr/m{sup 3} for 30 days; another, to 11 mg. Zr/m{sup 3} for 60 days. A third group was exposed to a mist of ZrCl{sub 4} at a level of 6 mg. Zr/m{sup 3} for 60 days. Zirconium oxide produced no significant changes in mortality, growth rate, blood nonprotein nitrogen or fibrinogen, urinary protein, hematological values or histological structure. Zirconium tetrachloride at 6 mg. Zr/m{sup 3} gave questionable changes in blood hemoglobin concentration and red cell counts of dogs and a slight increase in mortality of rats and guinea pigs. Inhaled zirconium compounds deposited primarily in the lung and pulmonary lymph node, with a fraction of a per cent in the bone and considerably less in the soft tissues. (auth)

Investigation to evaluate some of the designs, techniques, and methods for fabrication of a root pass.

"Approximately 2,000 flights of rocket-propelled models have been made in which model configuration, model size, type and number of booster rockets, number of booster stages, and booster arrangements varied. A brief summary of the results obtained with some of the more unusual arrangements, descriptions of boosting hardware and techniques, and discussions of some factors responsible for the choice of these configurations are presented in this paper. The results show that unconventional boosting techniques may be used successfully when conventional tandem arrangements are unsuitable or unwieldy" (p. 1).

Report presenting an investigation of the intensity of root-mean-square pressure pulsations and root-mean-square normal-force-coefficient fluctuations conducted on two high-lift airfoils and two 6-series airfoils. Results regarding the factors affecting comparison of data from various test facilities, root-mean-square pressure pulsations, and root-mean-square force fluctuations are provided.

From introduction: This bibliography is an annotated list of selected reports that were publicly available as of May 31, 1956, pertaining to the uranium content and/or radioactivity of igneous and metamorphic rocks and minerals in the United States.

"This bibliography is an annotated list of selected reports that were publicly available as of May 31, 1956, pertaining to the uranium content and/or radioactivity of igneous and metamorphic rocks and minerals in the United States, Alaska, and Hawaii."