Influence of cell wall polysaccharides on fruit juice technology

Readily processed clear fruit juices contain variable amounts of colloidally dissolved pectic substances. Separation of fruit juice polysaccharides by anion-exchange-chromatography yielded mainly arabinogalactans (type II) and rhamnogalacturonans. The addition of small amounts of the residual pectins to colloid free juices resulted in a up to 60 % reduction of the flux rates in micro- and ultrafiltration systems.     

Minimizing the Size of Vertexlights in Simple Polygons

We show that given a simple Polygon P it is NP‐hard to determine the smallest α ∈ [0, π] such that P can be illuminated by α‐vertexlights, if we place exactly one α‐vertexlight in each vertex of P.     

Radioluminescence dating of sediments: methodological aspects

Radioluminescence (RL) at 865 nm (1.42 eV) — a characteristic of potassium feldspar — has been applied successfully in the dating of Quaternary sediments. The signal can be interpreted as the infrared (IR)-emitting electron transition into a light sensitive trap. Direct measurement of the electron density is thus possible, and this is the basic advantage of this new method. Further investigations have been carried out to develop a precise and reliable IR-RL dating procedure. Besides the already applied additive dose total bleach technique, that of total bleach regeneration and a combination of both (slide technique) were tested in the dating of different aeolian and waterlaid sediments. New bleaching experiments show that about 10 min of light exposure (about 300–700 nm) is sufficient to reach the saturation level of the IR-RL signal. Palaeodose determinations of recently deposited sediments result, in most cases, in an age equivalent to <6 ka. The results of spectral RL measurements suggest that use of non-spectral-resolving detection systems would require an interference filter to reject the unwanted influence of a red RL emission wave-band.     

SIMS Profiling and TEM of CVD Films on Multi-Filament Samples

 A suitable fibre coating is essential to obtain optimal fibre-matrix interaction in fibre-strengthened composite materials. Thin films (∼100 nm) of silicon carbide, turbostratic carbon, and boron nitride were deposited by CVD as single or double layers on commercial multi-filament fibres in a continuous process. The fibre material itself may be carbon, alumina, silicon carbide, or a quaternary ceramic of SiCBN. The application of MCs⁺-SIMS enables one to determine the composition (including impurities of H and O) of various fibre coating materials with an accuracy of at least 20% relative. Due to the special geometry of the multi-filament samples the depth resolution of the SIMS depth profiles is limited, nevertheless, layered structures and some details of the interface between coating and fibre can be studied. The depth calibration of the SIMS depth profiles is derived from sputter rates established on flat samples with a composition similar to that of the fibre coating material. However, the obtained film thicknesses are not extremely different from the values derived from TEM on cross sections of coated fibres.     

Discovery Learning Using Chemland Simulation Software

We describe in this paper a set of computer-based simulations for use in general chemistry courses. We detail a discovery-based method of teaching, whereby students are led to discover concepts through guided-inquiry use of the simulation modules. Three methods of using the software are described, as is the development process we have employed. Finally, we describe our evaluation studies of the effects of our methodology and the use of a scientific reasoning instrument. The software is available free for download as part of this article.     

Die Kristallstruktur von K[F5W(≡NCl)]

Crystal Structure of K[F₅W(≡NCl)] Orange single crystals of K[F₅W(≡NCl)] have been formed as a by‐product from the reaction of tungsten nitrido chloride, WNCl₃, with Me₃SnF in the presence of potassium fluoride in toluene suspension. K[F₅W(≡NCl)] crystallizes in the monoclinic space group P2₁/c with four formula units per unit cell. Lattice dimensions at –83 °C: a = 1145.9(3), b = 770.4(2), c = 772.5(2) pm, β = 99.91(1)°, R₁ = 0.0742. The compound forms an ionic structure with octahedral [F₅W(≡NCl)]^– ions with a nearly linear arrangement of the N‐chloroimido ligand group W≡N–Cl (bond angle 173°, WN distance 174 pm). The K⁺ ions link the anions via K…F contacts and coordination number eight to form double layers along [100]. The layers itself are associated by short bounding Cl…F contacts of 279 pm.