8,278 research outputs found
Deformation processes in forging ceramics Progress report, 19 Jun. - 19 Sep. 1969
Deformation processes involved in forging of polycrystalline oxide ceramic
Deformation processes in forging ceramics Progress report, 19 Dec. 1969 - 19 Mar. 1970
Deformation processes in forging ceramic
High temperature compounds for turbine vanes
Fabrication and microstructure control studies were conducted on SiC, Si3N and composites based on Si3N. Charpy mode impact testing to 2400 F established that Si3N4/Mo composites have excellent potential. Attempts to fabricate composites of Si3N4 with superalloys, both by hot pressing and infiltration were largely unsuccessful in comparison to using Mo, Re, and Ta which are less reactive. Modest improvements in impact strength were realized for monolithic Si3N4; however, SiC strengths increased by a factor of six and now equal values achieved for Si3N4. Correlations of impact strength with material properties are discussed. Reduced MgO densification aid additions to Si3N4 were found to decrease densification kinetics, increase final porosity, decrease room temperature bend strength, increase high temperature bend strength, and decrease bend stress rupture properties. The decrease in bend strength at high temperature for fine grain size SiC suggested that a slightly larger grain size material with a nearly constant strength-temperature relation may prove desirable in the creep and stress rupture mode
The Algebra of Strand Splitting. I. A Braided Version of Thompson's Group V
We construct a braided version of Thompson's group V.Comment: 27 page
Fixation of virgin lunar surface soil
Two systems are shown to be suitable for fixing loose particulate soils with a polymer film, without visually detectable disturbance of the soil particle spatial relationships. A two-component system is described, which uses a gas monomer condensible at the soil temperature and a gas phase catalyst acting to polymerize the monomer. A one-component system using a monomer which polymerizes spontaneously on and within the top few millimeters of the soil is also considered. The two-component system employs a simpler apparatus, but it operates over a narrower temperature range (approximately -40 to -10 C). Other two-component systems were identified which may operate at soil temperatures as high as +100 C, at relatively narrow temperature ranges of approximately 30 C. The one-component system was demonstrated to operate successfully with initial soil temperatures from -70 C or lower to +150 C
Dry matter yields and quality of organic lupin/cereal mixtures for wholecrop forage
In view of climate change predictions and the general desirability of increasing the amount of home grown protein, a case exists for the investigation of lupins and lupin/cereal bicrop combinations as wholecrop forage on organic farms. A replicated randomised block trial is described which took place at the Royal Agricultural College, Cirencester, in 2005. This involved spring sown blue, white and yellow lupins, millet, wheat and triticale and lupin/cereal bi-crops. Data for dry matter yields for wholecrop silage, crude protein, MAD fi bre content and estimated ME, are presented for a single harvest. It is concluded that white lupins and white lupin bi-crops with spring wheat or triticale offer the best prospects for a viable wholecrop forage crop in an organic situation
Forest diagrams for elements of Thompson's group F
We introduce forest diagrams to represent elements of Thompson's group F.
These diagrams relate to a certain action of F on the real line in the same way
that tree diagrams relate to the standard action of F on the unit interval.
Using forest diagrams, we give a conceptually simple length formula for
elements of F with respect to the {x_0,x_1} generating set, and we discuss the
construction of minimum-length words for positive elements. Finally, we use
forest diagrams and the length formula to examine the structure of the Cayley
graph of F.Comment: 44 pages, 70 figure
Deformation processes in forging ceramics Summary report, Jun. 1969 - Aug. 1970
Deformation processes in forging polycrystalline oxide ceramic
THE LOW-SPEED STATIC LONGITUDINAL AND LATERAL-CHARACTERISTICS OF A DELTA-WING MODEL WITH FIXED AND FREE-FLOATING CANARD SURFACES
Low-speed static longitudinal and lateral characteristics of delta-wing model with fixed and free-floating canard surface
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