Sulfur content of rapessed oils

Sulfur contents in rapeseed oils were determined by reduction with Raney nickel, acidification, and titration of released H₂S with mercuric acetate. The sulfur contents decreased with successive steps of industrial processing, i.e., crude oil, 17–31 ppm S; degummed, 16 ppm; alkali refined, 4–9 ppm; bleached, 3–5 ppm; and deodorized, <1 ppm. Laboratory-extracted oil from sound seed contained no detectable sulfur, regardless of the glucosinolate content of the seed. Heating of the seed or addition of water to the seed prior to extraction increased the sulfur in the oil-less, however, for low-glucosinolate seed than for high-glucosinolate seed. Laboratory-extracted oils from green, frost-damaged, and bin-heated seed contained appreciable amounts of sulfur. Contribution No. 403, Department of Plant Science, University of Manitoba.     

Improving the optical properties of float glass

The nature of the defects that cause optical distortions in glass is analyzed. It was found that 70% of the optical defects in float glass is due to streak formation in the melt bath. Methods were developed for manufacturing float glass that increase its quality with respect to the optical indexes.     

Improving the processing properties of chlorinated PVC resins

An earlier paper (1) established the need for new compounding technology to deal with changes in melt flow resulting from the postchlorination of PVC resins. The present work attacks the more-than-doubled melt viscosity of chlorinated PVC as measured in stabilized resin. The potential for marked reduction in viscosity. improvement in processing stability, and retention of marketable product properties is explored. The development process including the definition of performance requirements, test methods used, and resulting balance of properties is described.     

Improving the post-experiment properties of stein's two-stage procedure

We show that the properties of stein's(1945) two-stage test conditional on an observed ancillary stastistic are such that one may be concerned aboutt its performance in particular individual experiments. We present a new two-stage t-test which has preferable conditional properties under the null hypothesis and we describe a group sequential Stein-based test with appealing properties under null and alternative hypotheses.Study of our new two-stage test reveals a surprising feature of Stein's original procedure which illustrates how the requirements of conditional acceptability and admissibility may come into conflict.     

Monogalactosyl diglyceride and digalactosyl diglyceride from commercial rapessed “lecithin”

By silicic acid column separation small quantities of glycolipid-rich fractions have been isolated from commercial Swedish rapeseed “lecithin.” Major components in these fractions are monogalactosyl diglyceride and digalactosyl diglyceride which have been identified by R_f on thin layer chromatography specific color reactions and IR spectrometry. The fatty acid patterns of the galactolipids are different from those of the major phospholipids of the same product, with less of palmitic and oleic and considerably more of linolenic acid.     

Improving the physicomechanical properties of acetate fibres and films

Conclusions It is possible to modify acetate fibres during the spinning process by adding crosslinking agents (dimethylolethyleneurea or dimethyloldihydroxyethylurea) to the spinning solution with subsequent heat-treatment of the fibre.The modified fibres have improved elastic properties (crease resistance, resistance to double bending) while preserving their strength characteristics.Deceased.Translated from Khimicheskie Volokna, No. 1, pp. 38–40, January–February, 1983.     

Improving the mechanical properties of polypropylene via melt vibration

The effect of melt vibration on the mechanical properties of polypropylene prepared by low-frequency vibration-assisted injection molding (VAIM) has been investigated. With the application of melt vibration technology, the mechanical properties of polypropylene are improved. The yield strength increases with the increment of the vibration frequency, and a peak stands at a special frequency for VAIM; the elongation at break decreases first and then increases with increasing vibration frequency, and a valley stands at a special frequency. The tensile properties increase sharply at an enlarged vibration pressure amplitude with sharply decreased elongation at break. The Young's modulus and impact strength also increase with the vibration frequency and pressure vibration amplitude. When it is prepared at 59.4 MPa and 0.7 Hz, the maximal yield strength is approximately 40 MPa versus 33.7 MPa for a conventional sample; an 18.7% increase in the tensile strength is produced. Self-reinforcing and self-toughening polypropylene molded parts have been found to be prepared at a high vibration frequency or at a large pressure vibration amplitude. Scanning electron micrographs have shown that, in the vibration field, the enhancement of the mechanical properties is attributable to more pronounced spherulite orientation and increased crystallinity in comparison with conventional injection moldings. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Plasma and lipoprotein lipid peroxidation in humans on sunflower and rapessed oil diets

The effects of natural mixed diets on lipid peroxidation were investigated in humans. In the first study, 59 subjects were fed a rapeseed oil-based diet rich in monounsaturated fatty acids (MUFA) and a sunflower oil-based diet rich in polyunsaturated fatty acids (PUFA) in a cross-over manner for three and a half weeks. The lipid peroxidation products in plasma were determined by measuring conjugated dienes and malondialdehyde (MDA). In a second study, plasma thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides, and the susceptibility of very low density lipoprotein + low-density lipoprotein (LDL) toin vitro oxidation were measured from subjects fed similar MUFA and PUFA diets for six week diets. No significant differences in plasma MDA or conjugated diene concentrations were found after the rapeseed oil diet or the sunflower oil diet in Study 1. In the second study, a small but significant decrease (P<0.05) in both lipid hydroperoxides and TBARS was observed in the LDL fraction after the sunflower oil diet. Thein vitro oxidation gave opposite results, showing increased oxidation after the sunflower oil diet. Despite a high intake of α-tocopherol during the oil peroids, no increase in plasma α-tocopherol was noticed in either study. The results suggest that moderate changes in the fatty acid composition in the Western-type diet may be adequate to affect lipoprotein susceptibility to oxidationin vitro, but there is considerable disparity with some indices ofin vivo lipid peroxidation.     

Cardiopathogenicity of soybean oil and tower rapessed oil triglycerides when fed to male rats

The triglycerides of soybean oil were purified by molecular distillation and those of Tower rapeseed oil by molecular distillation and adsorption chromatography. The original oils and the purified triglycerides were incorporated in semisynthetic diets at 20% by weight and fed for 16 weeks to weanling male Sprague-Dawley rats to compare the nutritional and pathological effects of the oils and their triglyceride fractions on rats. The study was carried out at two independent laboratories. No significant differences were observed between the results of the two establishments. The incidence of myocardial lesions was significantly higher in rats fed Tower rapeseed oil than in those fed soybean oil. Purification of the triglycerides by molecular distillation and adsorption chromatography appeared to have no major effect on the incidence of myocardial lesions. This supports our previous findings that the cardiopathogenicity of the test oils to rats resides in the triglycerides of these oils. Contribution No. 832 from Animal Research Institute and No. I-78 from Engineering and Statistical Research Institute.