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Abstract When polymers are extruded from a reservoir through a capillary the extrudate diameter is generally greater than the capillary diameter. Experiments with polyethylene show that the extent of this extrudate swelling depends, at constant shear stress, on the length‐to‐radius ratio of the capillary even though t…
The work-hardening properties of niobium single crystals grown by electron-beam zone-melting have been investigated over a wide range of purities, orientations, temperatures and strain-rates. Three stages of hardening are observed after the onset of plastic flow. The initial flow stress decreases with increasing purit…
Abstract Resinous materials have long been used to aid in the processing of rubber and to impart special properties to the vulcanized product. Resins have been described as various solid or semisolid organic substances. Originally, naturally occurring resins such as rosin were employed but with the advent of synthetic…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOptically Active Polyamides. Poly-D(-)-β-methyl-ϵ-caprolactamC. G. Overberger and H. JablonerCite this: J. Am. Chem. Soc. 1963, 85, 21, 3431–3435Publication Date (Print):November 1, 1963Publication History Published online1 May 2002Published inissue 1 November 1963https://do…
A semiempirical formula is developed which yields values for the differential dose albedo of gamma rays on concrete. Gamma rays of incident energies 0.2, 0.5, 1.0, 2.0, 4.0, 6.0, and 10.0 Mev are considered. Results of the semiempirical formula are compared with values derived from Monte Carlo calculations for the bac…
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
Abstract The crosslinking efficiencies of dicumyl peroxide in SBR, cis ‐polybutadiene, acrylonitrile–butadiene rubber, and polychloroprene have been measured. For the first two rubbers approximately ten crosslinks are formed per molecule of peroxide decomposed, while for the acrylonitrile–butadiene rubber an efficienc…
The glow peak emission due to impurities in calcite, dolomite, magnesite, aragonite, and anhydrite have been investigated by measuring and interpreting the associated spectra. The impurities considered are Mn++, Pb++, Zn++, and Sb3+.The emission spectra due to Mn++ are interpreted on the basis of crystal field theory…
Magnesium oxide prepared by calcining the carbonate at 1000°C was sintered at 1800°C and ground under methanol. Well‐sized 2 to 5 and 5 to 10 μ fractions were separated. After outgassing at 550°C in vacuum, the powders were hydrated at various temperatures to 98°C in a wide range of water vapor pressures, and the reac…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Synthesis of Secondary and Tertiary Amines by Borohydride Reduction1Karl A. SchellenbergCite this: J. Org. Chem. 1963, 28, 11, 3259–3261Publication Date (Print):November 1, 1963Publication History Published online1 May 2002Published inissue 1 November 1963https://pubs.ac…
The initial sintering kinetics of alumina have been studied by measuring the isothermal shrinkage of compacts of several alumina powders in air. The shrinkage of these compacts can best be described by a grain‐boundary vacancy diffusion model for the temperature range 1200° to 1600°C. The behavior of the compacts is c…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOXYGEN ADSORPTION RELATED TO THE UNPAIRED d-ELECTRONS IN TRANSITION METALSM. L. B. Rao, A. Damjanovic, and J. O'M. BockrisCite this: J. Phys. Chem. 1963, 67, 11, 2508–2509Publication Date (Print):November 1, 1963Publication History Published online1 May 2002Published inissue…
Abstract The purpose of this article is to review the developments in antioxidants for rubber over the past 25 years since the publication of Davis and Blake's “Chemistry and Technology of Rubber”. The intent is to provide a guide for rational use and further development. Accordingly, the organization of the material…
The anisotropy of nonwoven fabrics of various types has been studied in terms of modulus, strength, breaking extension, and fiber orientation. Polar diagrams for these quantities are given. Another important factor is the degree of curl in the fibers, and results are compared from different types of fabric and differe…
SUMMARY: The experiments described establish the importance of the pentose cycle in carbohydrate breakdown by Staphylococcus aureus. No Entner-Doudoroff pathway was found. Another feature is the extensive glucose effect: growth in glucose enhanced glycolysis suppressed the Krebs cycle, decreased the activity of the pe…
The temperature dependence of the X-ray diffraction intensity was precisely measured in order to clarify the nature of the ferroelectric phase transition in NaNO 2 . At the transition point, 163°C, the integrated intensity of the Bragg reflection decreases quite abruptly and distinct satellite peaks appear which are o…
Abstract Theoretical and experimental work is described which leads to a novel hypothesis for explaining the selectivity in heterogeneous vapor phase hydrocarbon oxidation catalysis. Two essential postulates of the hypothesis are: The oxygen atoms must be distributed on the surface of a selective oxidation catalyst in…
Abstract The primary purpose of this paper is to summarize some of the general relationships between chemical structure and transition temperatures for polymers. In addition to the two primary transitions, the melting point T m , and the glass transition T G , other transitions occurring either below T G or between T…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHIGH-TEMPERATURE CHEMISTRY OF THE RUTHENIUM—OXYGEN SYSTEM1Wayne E. Bell and M. TagamiCite this: J. Phys. Chem. 1963, 67, 11, 2432–2436Publication Date (Print):November 1, 1963Publication History Published online1 May 2002Published inissue 1 November 1963https://pubs.acs.org/…
The microstructures of deformed copper-gold, copper-aluminum, copper-zinc and magnesium-aluminum alloys were examined by transmission electron microscopy. These specimens were further examined after exposure to solutions which do and do not cause stress corrosion cracking. Exposure to "cracking" solutions resulted in…