Effect of the Degree of Phosphorylation on the Crystallinity of Native Potato Starch

X-ray diffraction technique, combined with digital image processing was used to compare the crystallinity of native starch from a number of potato varieties, differing in the degree of phosphorylation. The crystallinity was found to decrease linearily with an increased degree of phosphorylation. Based on earlier observations of the gelatinization enthalpies, it was assumed that the C-6 phosphates, which have an orientation out of the α-helices disturb the crystallization of the amylopectin during the starch synthesis. The C-3 phosphates, which are located in the interior parts of the α-helices, are not believed to interfere with the crystal structure.     

An Innovative Submerged Entry Nozzle Design for Billet and Bloom Casting

Fluid flow in the mold has a significant impact on the quality of continuously cast steel products.Since it is strongly influenced by the SEN design,attention h...     

Photoinitiierte Polymerisation mit Dialkoxythiocarbonyldisulfiden – eine Polymerisationsreaktion mit Primärradikalabbruch

Photoinitiated Polymerization with Dialkoxy Thiocarbonyl Disulfides – a Polymerization Reaction with Primary Radical Termination The photoinduced free radical polymerization of methyl methacrylate (MMA) and some other vinyl monomers using dialkoxy thiocarbonyl disulfides ( 1 – 4 ) as photoinitiators was studied. The photolysis of these initiators leads to cleavage of the S S bond, which was determined by spin trapping experiments with phenyl tert-butyl nitrone. No evidence was found for a further thermal decomposition of the primary alkoxy thiocarbonyl sulfide radicals (R·) at room temperature. In the absence of scavengers the primary radicals react back exclusively to the initial compounds, due to a strong cage effect. By means of UV spectroscopic measurements and in the presence of MMA the quantum yields of the initiator decomposition were detected to be 0.8. The polymerization of acrylic and methacrylic derivatives can be initiated by the R·, contrary to the situation with fumarates and maleates. The mechanism of MMA polymerization depends on the light intensity absorbed by the initiators. At high intensities the combination of primary and polymer radicals terminates the chain reaction. This follows from the measured monomer exponent of α = 2, the light intensity exponent of β = 0,2 and the number of thiocarbonyl end groups of 2 in the polymers isolated. Contrary to this, in the low intensity region the experimental data obey the ideal kinetic equation. Kinetic modelling gives evidence for an interaction of the monomer with the cage radicals.     

Catalytic effects of metals of the iron subgroup on the chlorination of titanium carbide to form nanostructural carbon

The effect of the reaction temperature and the metals of an iron subgroup on the thermo-chemical treatment of titanium carbide with a chlorine gas and their influence on the carbon structure obtained thereby was studied. Different analytical methods such as porosity measurements, X-ray diffraction spectrometry and a high-resolution electron microscopy revealed the catalytic behaviour of the above-mentioned metals, which appeared to support the formation of graphitised carbon at much lower temperatures compared to those needed for the ordinary thermo-chemical chlorination of titanium carbide.     

Influence of dietary partially hydrogenated vegetable and marine oils on membrane composition and function of liver microsomes and platelets in the rat

The aim of the present study was to investigate the influence of partially hydrogenated vegetable and marine oils on membrane composition and function of liver microsomes and platelets with particular reference to the metabolism of linoleic acid and the production of arachidonic acid metabolites. Four groups of male weanling rats were fed linoleic acid supplemented diets containing 20% (w/w) of partially hydrogenated low erucic acid rapeseed oil (HLRSO), partially hydrogenated herring oil (HHO), olive oil (OO) and trierucin + triolein (TE) for 10 weeks. An additional two groups were fed partially hydrogenated low erucic acid rapeseed oil and partially hydrogenated herring oil without linoleic acid supplementation (HLRSO- and HHO-, respectively). Substantial amounts oftrans fatty acids were incorporated into liver microsomes (12.6% in group HLRSO) and platelets (7.0% in group HLRSO-). This incorporation was not dependent on the dietary linoleic acid level. Hepatic microsomal Δ⁵-desaturase activity was significantly increased after HLRSO feeding compared to OO feeding. Δ⁶-Desaturase activity did not vary in the linoleic acid supplemented groups. Both Δ⁵- and Δ⁶-desaturase activities were significantly increased in groups without linoleic acid supplementation. Docosenoic acid was incorporated into platelet phospholipids in contrast to liver microsomes. In the platelet, docosenoic acid seemed to have a special preference for phosphatidylserine. Very small amounts were incorporated into platelet phosphatidylinositol. Feeding diets HLRSO, HHO and OO did not influence rat platelet cyclooxygenase or 12-lipoxygenase activity. Platelets from rats fed TE, however, produced significantly less 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) than platelets from rats fed OO. Feeding of HLRSO- and HHO- resulted in a significantly diminished production of the arachidonic acid metabolites 12-HETE, 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and 6-keto-prostaglandin F_1α in stimulated platelets and aorta. Thus, high dietary levels oftrans isomers of monoenoic acids do not interfere with platelet cyclooxygenase or lipoxygenase activity provided sufficient amounts of linoleic acid are available.     

New developments at JET in diagnostics, real-time control, data acquisition and information retrieval with potential application to ITER

In magnetic confinement fusion, the operation of next generation devices will be significantly different compared to present day machines. The duration length of the discharges will require abandoning the traditional paradigm of processing and storing the data after the shot. In fact most information will have to be made available in real-time. The significant issues of machine protection will require more sophisticated and at the same time more robust feedback control schemes. Another very important issue emerged in the last years of JET operation, and which is expected to become more severe in ITER, is the large amount of data to be analysed, which cannot be handled in the most efficient way with traditional methods.In order to prepare for the operation of ITER, some tests are being performed at JET. The capacity of the real-time network has increased in the last years, and many more systems, mainly diagnostics have been connected to it in order to test their reliability and to assess the quality of the information they can provide for feedback control. To reduce the amount of data, a prototype of real-time adaptive data acquisition techniques is being implemented, to adjust the acquisition frequency to the time resolution of the phenomena to be analysed in the plasma. Lossless data compression techniques have been refined and various intelligent signal processing methods have already been implemented to allow an easier and more objective first screening of the data. To allow scientists from wide and diffuse communities to participate in the scientific and technical programme, various innovative tools for remote participation and experimentation are also being actively investigated.     

Influence of different wood flour fractions on the mechanical properties of injection molded WPC with cellulose propionate

This research investigated the effect of different fractions of commercial wood flour (Type c100 from JRS, Germany) on mechanical and physical properties of wood-polymer composites (WPC). The fractions were named regarding the mean lengths of their particles in µm; 80, 130, 255, 405 and 485. The composite samples were manufactured with 30 wt% of wood flour fractions of all five groups as well as the not fractionated flour, and 70 wt% of cellulose propionate (CP). The melt mass-flow rate (MFR) of the different granules, tensile strength, and modulus of elasticity, flexural strength, flexural modulus and the impact strength of the injection molded specimens as well as the water uptake were determined in this study. WPCs with the specific size range used in this investigation exhibited improved strength and modulus of elasticity in tensile and flexural tests, compared to pure CP. Using fraction 255, the mechanical properties increased the most. Tensile strength rose by 28 and 13% compared to CP and to WPC with the not fractioned wood powder, respectively. Fraction 255 increased flexural strength by 33 and 5% compared to CP and WPC with the not fractioned flour. The MFR (tested at 190 °C with 7.16 kg) of WPC_255 is the lowest with 2.3 g/10 min. Composites with the smallest particles showed the least water uptake.