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991.
Solidification after extrusion of coaxial cables has been experimentally simulated. Solidification tests were performed with two HDPE grades and under several pressures; the extrusion velocity was varied in a suitable range so as to detect the critical velocity for void formation. A qualitative analysis of the void formation mechanism is carried out, and the predicted trends favorably compare with the critical velocity data. 相似文献
992.
Unsaturated Polyester resins were prepared by the reaction of cinnamylsuccinic acid with saturated diols, namely, ethylene, diethylene, propylene, dipropylene, tetramethylene, and hexamethylene glycols, and the unsaturated diols, namely, 1,4-butene- and 1,4-butynediols. All the polyester resins obtained have been characterized and were found to cure with styrene, with relatively low conversions. The properties of the cured polyesters in the form of films were determined. IR and 1H-NMR spectroscopy were used for both qualitative and quantitative analyses of the polyesters and their hydrolyzate products, after curing with styrene. 相似文献
993.
Mahmoud M. Abou el Leil Frank A. Camaratta Rocco R. DiGenova 《Journal of the American Ceramic Society》1985,68(1):18-C-
In-service fracture of helicopter windshields was studied. Simulated catastrophic fracture tests were conducted by firing alumina and steel spheres onto stationary tempered and as-received glass panels. The results were studied by Hertzian analysis and modified Auerbach's relations. Thermally tempered glass shows much higher impact resistance than that estimated from superposition of residual stresses. Subcritical impact sites exhibit slow crack growth in tempered plates, eventually leading to fracture of the entire plate. 相似文献
994.
J. K. FINK 《Journal of the American Ceramic Society》1985,68(3):139-142
This paper identifies the fuel properties for which more data are needed for fast-reactor safety analysis. In addition, a brief review is given of current research on the vapor pressure over liquid UO2 and (U, Pu)O2-x the solid-solid phase transition in actinide oxides, and the thermal conductivity of molten urania. 相似文献
995.
J. E. SHELBY 《Journal of the American Ceramic Society》1985,68(3):155-158
The glass-forming region for calcium aluminosilicate glasses has been determined. A number of properties of these glasses (thermal expansion coefficient, glass transformation and dilatometric softening temperature, and refractive index) have been studied. The results of these measurements suggeq that the structures of these glasses may not as closely resemble those of alkali aluminosilicate glasses as is commonly assumed. Evidence is presented which suggests that the binary calcium aluminate glasses may be phase separated. 相似文献
996.
J. T. DICKINSON L. C. JENSEN W. DAVID WILLIAMS 《Journal of the American Ceramic Society》1985,68(5):235-240
We present measurements of the electron, positive ion, and photon emission accompanying the fracture in vacuum of poly-crystalline 95/5 lead zirconate-titanate. The intensities of the charged-particle components of this fractoemission are shown to depend strongly on the direction (relative to the direction of fracture) and magnitude of polarization. The most intense emission is observed when the fracture surfaces are perpendicular to the polarization direction. The emission intensity increases monotonically with polarization. These results are interpreted in terms of a model involving charge separation on the fracture surfaces leading to a microdischarge during fracture. Implications to the interpretation of triboluminesence effects are discussed. 相似文献
997.
G. BEN ABDERRAZIK F. MILLOT G. MOULIN A. M. HUNTZ 《Journal of the American Ceramic Society》1985,68(6):302-306
To determine the transport properties of oxide scales growing on an alloy, a laboratory apparatus was developed which allows plotting of characteristic V = f (i) curves and oxidation with an applied electric field. The apparatus and formalism used are described; it appears that such experimental procedures allow determination of the mean ionic transport number, ti; the conductivity values σ, σi , and σ,e ; and the effective charge, Z*, of the moving species in the oxide scale (A12 O3 in the present case). 相似文献
998.
Previous solid state analyses of sintering in Ti4+ -doped-commercial alumina are shown to be in error because a liquid phase exists in the appropriate region of the Al2 O3 −TiO3 −Na2 Ophase diagram at least by 1350° C, a temperature lower than that at which "solid state" studies were conducted. It is suggested that liquid-phase sintering is a much more common occurrence than was realized formerly. 相似文献
999.
D. A. Morgan D. B. Shaw M. J. Sidebottom T. C. Soon R. S. Taylor 《Journal of the American Oil Chemists' Society》1985,62(2):292-299
The results presented in the literature, which attempt to elucidate the mechanisms by which triglyceride oils are bleached
by earths, are reviewed. The impact of this work and how the mechanistic proposals affect changes in oil properties are considered,
with particular emphasis on the needs of the palm oil processor. Important properties include color, metals and phosphorus
content and oxidative stability of the oil.
Investigations made in our own laboratories have been aimed at elucidating the effect of varying physical and chemical properties
of the bleaching earth on the quality of bleached and deodorized oils. Techniques used in this work are pore-size distribution,
surface area, scanning and transmission electron microscopy and a variety of chemical and X-ray analysis methods.
The ability to vary such parameters in montmorillonite clays by alteration of process conditions to give materials with specific
performance characteristics is demonstrated.
Comparisons are made between acid-activated montmorillonites and other clay types. 相似文献
1000.
A. Southworth 《Journal of the American Oil Chemists' Society》1985,62(2):250-254
Events leading up to the introduction of the pollinating weevil (Elaeidobius kamerunicus) into Malaysian plantations are described, and the effect of this on the industry is discussed. The main benefits so far
are increased kernels and savings in estate pollination costs. It is as yet too early to assess other benefits. The changes
in bunch composition have given rise to some processing problems, i.e., sterilization and nut processing, which are currently
being corrected.
There have been no major changes in processing procedures, but process developments, such as the use of decanters, computerization,
steam utilization and quality improvements, are being made. A review of effluent treatment from palm oil mills shows that
most mills conform to government standards using mostly biological digestion processes and land application. Research and
development projects are discussed. These include tissue culture and utilization of byproducts. 相似文献