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991.
Properties and compound types were examined in detail for tar-sand bitumens representative of four major deposits in Utah and Alberta. Methods for bitumen extraction, separation, and compound type (functional group) analysis are presented. Results of the analyses are compared with each other and with results in the literature for tar-sand bitumens and petroleum. Comparison of the results of Utah bitumens with the Athabasca bitumen provides a basis for evaluation of the Utah bitumens because considerable information about the processing characteristics of the Athabasca bitumen has been reported. Simulated distillation and Chromatographic separation data indicate that, in general, the tarsand bitumens most closely resemble Wilmington petroleum with respect to hydrocarbon/non-hydrocarbon distribution, especially in the non-distilling portion (the distillable portions, mainly hydrocarbons, are similar for all samples). Tar-sand bitumens were also shown to differ significantly from one another, principally in the amounts and kinds of heteroatomic compound types present. This information is important because of the effects that composition has on recovery and refining processes. Analyses of the chemical functionalities also provide a basis for developing correlations between bitumen composition and the recovery and processing characteristics of the bitumen.  相似文献   
992.
993.
A method is presented to identify flow model parameters from radioactive signals with a high noise content. The method is based on the two detection points method with a highly accurate identification of the parameters by optimization in the frequency domain. The study of dispersed phase of a pulsed column with perforated plate using this method has shown evidence that there are operating conditions for which the piston-diffusion flow does not describe well the behavior of the dispersed phase.  相似文献   
994.
Current methods for determining the activity of long chain quaternary ammonium compounds (QACS) are based either on dye partition, titration, or colorimetric analysis. The two major disadvantages of these methods are the disparity of partition coefficients among differently constituted QACS and the difficulty in detecting visual end points. Some potentiometric titration methods for QACS have been reported in the literature. However, back titration techniques, as well as complicated electrode systems, are generally involved. A new potentiometric titration system is presented which uses aqueous sodium tetraphenylborate (TPB) solution as a titrant and a platinum-platinum electrode system to detect the end point. Standard potentiometric titration instruments may be used for this method. This new potentiometric method is superior in precision and accuracy to visual (colorimetric) methods. Original version presented at the 1986 Annual AOCS Meeting in Honolulu, HI.  相似文献   
995.
Mechanical properties of high density polyethylene (HDPE) extended to draw ratios in the 20–40 range have been determined and compared with corresponding properties of the polymers containing particulates including rutile, carbon black, iron oxide, and mica. Shrinkage of drawn structures was studied to temperatures near the fusion of the polymer host. The degree of interaction at polymer/additive interfaces was varied by surface coating certain of the solids with standard coupling agents. Solids were found to increase tensile moduli and to decrease shrinkage, particularly at higher exposure temperatures. The magnitude of changes due to the presence of solids was shown to depend on the apparent interaction at contacts between host and additive. In a dispersion–force matrix, like HDPE, benefits were optimized when the particulates were amphoteric or neutral, rather than having pronounced acid or base interaction potentials.  相似文献   
996.
光催化剂SrTiO3的制备及其性能的研究   总被引:7,自引:0,他引:7  
论述用化学液相共沉淀法制备SrTiO_3的最佳条件,及在不同的活化条件下对SrTiO_3光催化性能的影响。此外还研究了掺入过渡金属氧化物对SrTiO_3催化性能的改善。  相似文献   
997.
The mechanism of electroreduction of benzoic acid on mercury and lead cathodes has been investigated using cyclic voltammetry and constant potential electrolysis.The main reaction pathway was found to be via electron transfer to an adsorbed ion-pair on “cation bridge”, the presence of the cation stabilising the benzoate anion at the electrode surface.At potentials prior to its reduction the benzoate anion acts as a centre for catalytic hydrogen evolution.  相似文献   
998.
Many investigators associate the poor keeping properties of soybean oil with its linolenic acid content. On the other hand the high linoleic acid content is a desired property from a nutritional point of view. We have therefore developed a process for the preferential reduction of the linolenic acid content by selective hydrogenation. Conventional catalysts for the hydrogenation of fats have a rather low selectivity in this respect. When linolenic acid in soybean oil is hardened (e.g., with a nickel catalyst), most of the linoleic acid is converted into less unsaturated acids. It was found that linolenic acid is hydrogenated much more preferentially in the presence of copper catalysts than in that of nickel and other hydrogenation catalysts. At a linolenic acid content of 2%, soybean oil hardened with nickel catalyst contained about 28% linoleic acid, whereas with copper catalyst the hardened soybean oil contained 49% linoleic acid. By means of our process it is possible to manufacture a good keepable oil of, e.g., I.V. 115 and containing 1% linolenic acid and 46% linoleic acid. The storage stability of this product is comparable with that of sunflower-seed oil. A liquid phase yield of 86% is obtained after winterization at 5C for 18 hr. The high selectivity for linolenate reduction of copper catalysts must be ascribed to the copper part of the catalyst. Investigations into the structure of the catalyst indicate that the active center consists of copper metal crystallites; whether these centers are promoted by the carrier or traces of other substances is under investigation.  相似文献   
999.
The fatty acid composition of body lipids was determined by GLC for 14 species of saltwater fish, three species of freshwater fish and four species of shellfish. In addition, liver lipids of two species and egg lipids of one species were analyzed for comparison with the fish body lipids. The various species ranged from lean to fatty and contained from 0.7~15.5% oil in the tissues. Certain major fatty acids were found to vary widely among the species, as follows: 1.6~8.0% myristic, 9.5~33.4% palmitic, 2.0~11.2% palmitoleic, 5.2~29.1% oleic, 0.7~10.5% eicosenoic, 5.0~21.5% eicosapentaenoic, 0.2~11.6% docosenoic and 5.9~26.2% docosahexaenoic acids. Analyses of two separate mullet-oil samples illustrated the wide differences that are possible for a single species caught during different seasons. Significant differences in the amt of particular fatty acids were found in comparing freshwater-fish analyses with analyses for marine fish. Oysters and scallops showed large amt of pentaenoic and hexaenoic acids in their oils. Presented in part at the AOCS Meeting, New York, 1960.  相似文献   
1000.
The yield stress is a simple function of the deformation ratio in the direction of testing for specimens oriented by uniaxial or biaxial stretching or rolling. Unless the yield stress increases more rapidly than in proportion to the deformation ratio, there will be instability during tensile creep under high loads. The relative merit of various polymers differs for creep and stress relaxation. Fatigue and bend recovery are also related to the molecular structure.  相似文献   
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