Ver?nderungen des N?hrstoffgehaltes von Kondensmilch bei jahrelanger Lagerung

Zusammenfassung In Kondensmilchproben, die 1–4 Jahre bei 10–15° C gelagert waren, wurde der Gehalt an Carotin, Vitamin A, E, B₁, B₂ und C sowie Jod- und Verseifungszahl bestimmt. Der Gehalt an Carotin, den Vitaminen A und E sowie Jod- und Verseifungszahl wurde praktisch ebenso hoch gefunden wie in den ungelagerten Kontrollproben. Die wasserlöslichen Vitamine B₁, B₂ und C nahmen um ein Drittel des Gehaltes der Kontrollproben ab.     

CaZrO3 additives to enhance capacitance properties in BaTiO3 ceramic capacitors

The effects on the dielectric properties of BaTiO₃ of addition of CaZrO₃ (0–17 wt%) has been investigated. Dielectric constants ranging between 2500 and 15 500 have been obtained by using commercial grade raw materials with the starting dielectric constant of the undoped BaTiO₃ being 800. The capacitor dielectrics have also been analysed for their electrical properties, crystalline phases and microstructural features.     

Synthesis of nearly monodisperse embedded nanoparticles by separating nucleation and growth in ion implantation

We investigate the formation of nanoparticles of Au in SiO(2) by multiple ion implantation steps and intermediate anneals to isolate nucleation and growth, thereby producing a narrow particle size distribution. We discuss the effects of varying the initial nucleation dose and the growth temperature and establish guidelines for synthesizing nanoparticles with improved size uniformity. By this method, we have obtained a standard deviation of 16% on an average diameter of 1.68 nm, compared to 28% when no attempt is made to isolate nucleation and growth.     

Short communication: Consumer evaluation of milk high in conjugated linoleic acid

A consumer evaluation was undertaken to determine whether there were differences in the acceptability of milk from cows fed a control or a fish oil diet. The two treatments included a control diet of a 50:50 ratio of forage-to-concentrate and fish oil added to the control diet with 2% (on dry matter basis) added fat from menhaden fish oil. Milk from cows fed the control or fish oil diet contained 3.31 and 2.58% fat and 0.56 and 2.30 g of total conjugated linoleic acid/100 g of fatty acids, respectively. Consumer evaluation of control and fish oil milks found no difference in acceptability.     

Modelling the microstructural evolution during hot compression of low carbon steel

Compression tests have been performed on low carbon cylindrical specimens in the temperature range of 900–1100°C in a thermomechanical simulator at a strain rate of 10 s^?1. True stress/true strain and load-displacement curves have been characterised over a strain of 0 to 0.8 at above temperatures. The specimens were helium quenched after an incremental true strain of 0.2 for microstructural study. From the experimental data, flow stress of the material at high temperatures has been determined as a function of Zener-Hollomon parameter. The flow stress equation was employed in a coupled finite element flow formulation model to compute the load for various incremental displacements. The predicted results of load-displacement and change in specimen geometry during compression showed good agreement with the measured values. The predicted rise in temperature due to deformation was of the order of 52 to 34°C in the temperature range of 900 to 1100°C at a strain rate of 10 s^?1. The prior austenite grain size has been measured in the specimen compressed up to a strain of 0.6 at 1100°C and compared with the predicted austenite grain size employing the microstructural model. Metallographic study showed an equiaxed recrystallized grains network in most of the region at the center of the specimen with average grain size of 43 μm. A coarse deformed grain structure with few recrystallized grains at the intersection boundary of austenite grains was observed at the top surface and bulge surface with an average grain size of 74 and 84 μm, respectively. The model predicted the evidence of fully dynamically recrystallised grains at the center of the specimen with a grain size of 42 μm. The predicted grain size at the top and bulge surface has been calculated as 90 and 106 μm, respectively.     

Influence of Ag+-Na+ ion-exchange equilibriumon waveguide index profiles

The Ag⁺-Na⁺ ion-exchange process in a soda-lime silicate glass was studied at 330° as a function of composition of AgNO₃-NaNO₃ melt, mixing condition, and exchange time. The concentration profile of silver in glass was measured by atomic absorption spectroscopy and SEM technique. The surface index change and the index profile were determined from mode index measurement. Ion-exchange was modeled by an ion-diffusion limited process in the glass with an equilibrium chemical reaction at the melt-glass interface. A large value of 75 for the equilibrium constant at low-silver melt concentrations (<10^-2 mole fractions) shows that uptake of silver in glass varies in highly nonlinear fashion with the melt concentration. The results provide boundary conditions necessary for solution of the diffusion equation and design of single-mode waveguides     

1-O-acyl derivatives of glucose as non-penetrating inhibitors of glucose transport by hamster small intestine in vitro

1-O-acyl derivatives of glucose are not transported by the hamster small intestine in vitro. These derivatives, however, are potent inhibitors of the glucose transport system. 1-O-Decanoyl glucose is a competitive inhibitor of beta-methyl glucoside transport.     

Effect of matrix precipitation on cellular growth kinetics in an Al-28 at. % Zn alloy

The reported existence of two metastable miscibility gaps in the aluminium-zinc (Al-Zn) system is confirmed by an electron microscopic study of precipitate reversion in an Al-28 at. % Zn alloy. The metastable Guinier-Preston (G.P.) zones are replaced above ～125° C within minutes by a metastable rhombohedrally distorted f c c phase (R-phase). Consequently, the recently published calculations for the growth rate of the cellular reaction in the 100 to 250° C temperature range are revised in accordance with the nature of the continuous precipitate ahead of the advancing cell boundary. The observed growth rates are now shown to agree most satisfactorily with current theories of cellular decomposition as controlled by cell boundary diffusion and influenced by continuous precipitation in the matrix.     

Finite element analysis of LiNbO3 waveguides with Si orSi/SiO2 overlay

LiNbO₃ waveguides with Si overlays are emerging as a basic building block for a variety of integrated-optic components, including modulators, high-efficiency gratings, and narrowband WDM filters. However, the development and optimization of these devices are, in large part, hindered by the lack of understanding of the specifics of the Si-on-LiNbO₃ structure which appear to differ dramatically from those of the Si and LiNbO₃ waveguides, considered separately. In this work, we provide a specific insight into the waveguiding properties of vertically stacked Si-on-LiNbO₃ waveguides. In particular, we present a detailed theoretical analysis of the effect of the Si film on the modal characteristics (propagation constant and field distribution) of the structure. The vectorial finite element method (VFEM) is used to numerically investigate a step-index and graded-index single-mode channel waveguide in LiNbO₃, with a Si or Si/SiO₂ multimode overlay. We show that for ~70% of all Si thicknesses, in the range from 0 to 1.6 μm, the highest order normal mode of the entire structure has more than 99.9% of the total energy confined in the LiNbO₃ region, i.e., beneath the Si overlay. This fact is quite intriguing given the fact a planar Si layer of submicron thickness on bulk LiNbO₃ is already multimoded. Furthermore, we show that the effective mode index of the structure is considerably modified compared to that of the LiNbO₃ waveguide while the propagation loss is, on the other hand, practically unaffected (~0.3 dB/cm) even in the presence of the lossy Si film, as confirmed by our previous experimental results. Evidently, large modulation of the effective index and low-loss propagation provide an ideal combination of properties suitable for the fabrication of high-reflectance corrugated waveguide gratings, essential for a number of practical devices, in particular, WDM filters