Variation in fatty acid composition of ewes' colostrum and mature milk fat

Temporal content variations of approximately 70 C4–C24 fatty acids (FA) in colostrum and milk of ewes consuming winter diet were determined by gas chromatography. The content of monounsaturated, polyunsaturated and straight-chain saturated FA 14:0–16:0 in colostrum was higher whereas the content of 4:0–12:0, 18:0 and branched-chain saturated FA 15:0–17:0 was lower than that in mature milk. The effect of ewe breed on the FA profiles was not significant. The composition of FA changed most significantly 1–2 days after lambing in agreement with the time schedule of colostrum formation. Nevertheless, the content of FA further successively changed up to approximately the 6th day of lactation, whereas further changes up to the 60th day of lactation were smaller. This is consistent with the recommendation that ewes' milk is suitable for human consumption after six-to-eight days of lactation. The higher contents of palmitic and myristic acids in colostrum compared with mature milk suggest that FA composition in colostrum matches the changing needs of the growing lambs.     

Viscosity of glass-forming melt at the bottom of high-level waste melter-feed cold caps: Effects of temperature and incorporation of solid components

During the final stages of conversion of melter feed (glass batch) to molten glass, the glass-forming melt becomes a continuous liquid phase that encapsulates dissolving solid particles and gas bubbles that produce primary foam at the bottom of the cold cap (the reacting melter feed in an electric glass-melting furnace). The glass-forming melt viscosity plays a dominant role in primary foam formation, stability, and eventual collapse, thus affecting the rate of melting (the glass production rate per cold-cap area). We have traced the glass-forming melt viscosity during the final stages of feed-to-glass conversion as it changes in response to changing temperature and composition (resulting from dissolving solid particles). For this study, we used high-level waste melter feeds—taking advantage of the large amount of data available to us—and a variety of experimental techniques (feed expansion test, evolved gas analysis, thermogravimetric analyzer-differential scanning calorimetry, X-ray diffraction, and viscometer). Starting with a relatively low value at the moment when the melt connects, melt viscosity reached maximum within the primary foam layer and then decreased to its final melter operating temperature value. At the cold-cap bottom—the boundary between the primary foam layer and the thermal boundary layer—where physicochemical reactions of a melter feed influence the driving force of the heat transfer from the melt to the cold cap, the melt viscosity affects the rate of melting predominantly through its effect on the temperature at which primary foam is collapsing.     

Dynamic mechanical analysis and broadband electromagnetic interference shielding characteristics of poly (vinyl alcohol)-poly (4-styrenesulfonic acid)-titanium dioxide nanoparticles based tertiary nanocomposites

ABSTRACT

Novel tertiary nanocomposite films comprising of poly (vinyl alcohol) (PVA), poly (4-styrenesulfonic acid) (PSSA) and titanium dioxide (TiO₂) nanoparticles (NP_S) were prepared using simple solvent casting method. The structural, thermal, morphological, thermo-mechanical and electromagnetic interference (EMI) shielding properties of PVA/PSSA/TiO₂ nanocomposite films were investigated. The EMI shielding effectiveness (SE) of PVA/PSSA/TiO₂ nanocomposite films in the X and Ku band was found to be 12 dB and 13 dB respectively at 25 wt% TiO₂ NPs loading. These results demonstrate the possible applications of PVA/PSSA/TiO₂ nanocomposite films as low cost, lightweight and flexible material for EMI shielding.     

Numerical study on the spectroscopic ellipsometry of lamellar gratings made of lossless dielectric materials

The spectroscopic ellipsometry of lamellar gratings made of lossless dielectric materials is studied numerically by using the rigorous coupled-wave method with the use of Li's Fourier factorization rules [J. Opt. Soc. Am. A 13, 1870 (1996)], which are known to improve the convergence on the analyses of metallic gratings. Numerical results show that the calculation method also provides fast convergence on lossless gratings, and accurate values of the ellipsometric angles are obtained in very short computation times. Moreover, estimation of grating parameters is investigated by using a cost function defined by the average distance on the Poincaré sphere, and it is shown that the computation required for accurate estimation is possible in reasonable computation time.     

Mechanical testing of a FW panel attachment system for ITER

An objective of experiments and finite element simulations was to check the stiffness, the strength and the fatigue resistance of the attachment of the First Wall panels onto a shield block of blanket modules according to the ITER 2001 design. The panel has a poloidal key at the rear side (in so-called option A with the rear access bolting) and it is attached by means of special studs located on a key-way in the shield block. Special device for a test of stud tensile pre-load relaxation during a thermal cycling was developed. True-to-scale panels, the shield block mock-up and simplified studs were fabricated and the assembly was loaded alternatively by radial moment, poloidal force or poloidal moment simulating the loading during off-normal plasma operations. Thermal cycling led to an acceptable stud pre-load relaxation. Mechanical cycling caused neither the pre-load relaxation nor the loss of the contact in the key-way nor a damage of the attachment system. The combination of poloidal moment and radial force during vertical displacement events (VDEs) seems to be a most dangerous case because it could lead to the loss of the key–key-way contact.     

Properties of tin/plasma polymer nanocomposites

Thin composite layers (tin in plasma polymer matrix) were prepared in a stainless steel vacuum chamber. An RF powered magnetron with tin target was used to excite the discharge and to activate the monomer species (n-hexane). The gas mixture introduced comprised Ar and n-hexane vapours. The properties of the films and chemical composition were characterized by AFM (surface morphology), TEM and Electron tomography (bulk structure characterization), XPS and FTIR spectroscopy (chemical composition analyses). Current-voltage characteristics were measured to examine the electrical properties of the layers and their dependence on the deposition parameters.     

Polypyrrole and polyaniline prepared with cerium(IV) sulfate oxidant

The conducting polymers, polypyrrole and polyaniline, were synthesized by chemical oxidative polymerization of the corresponding monomers in 0.1 M sulfuric acid using cerium(IV) sulfate as the oxidant at mole ratios of oxidant-to-monomer ranging from 0.5 to 3. The yields of the oxidation products were determined, and the samples were characterized with respect to their elemental composition, molecular structure, and morphology. The conductivity of polypyrrole prepared in 0.1 M sulfuric acid, 10^?1 to 10⁰ S cm^?1, was higher compared with the conductivity of polyaniline prepared under the same conditions, 10^?3 to 10^?1 S cm^?1. The loss of mass after deprotonation with ammonium hydroxide is reported, and discussed in terms of the type of protonation as also reflected by FTIR spectroscopy. The conductivity of polypyrrole bases remained at relatively high level, 10^?5 to 10^?3 S cm^?1, while PANI bases became non-conducting, 10^?12 to 10^?10 S cm^?1. The polymers had a granular morphology in all cases.