NMR Study of Adsorbate Self-Diffusion in Porous Glasses

The NMR pulsed field gradient technique was used to study molecular transport in porous glasses. The adsorbent materials were produced by leaching phase-separated sodium-boron-silica glasses of different composition, then heat-treating. The pore diameters of the glass samples produced were within the interval 0.8 to 50 nm. Water, methanol, dodecane, and do-decene were used as adsorbates. The coefficients of adsorbate self-diffusion were found to decrease with decreasing pore diameter. In comparison with the neat liquids, a reduction in the adsorbate mobility (up to two orders of magnitude) was observed. For the larger pores, that decrease may be attributed to the tortuosity of the adsorbent, whereas the low diffusivities in the porous glasses with small pores are a consequence of the stabilizing effect of the rigid adsorbent framework.     

ISOLATION OF LYSOSOMES FROM EEL MUSCLE (ANGUILLA SPEC.)

The activities of two acid glycosidases have been determined in the white muscle of eel (round fish). The distribution pattern of these enzymes in the fractions obtained by differential centrifugation of homogenized muscle demonstrated that at least part of their activity originated from the lysosomes. Triton X-100, hypotonic solution and freezing/thawing were effective in releasing α-glucosidase from the lysosomes. Freezing and thawing of eel muscle (round fish) also resulted in the release of α-glucosidase activity.     

STABILITY OF FISH MUSCLE PARVALBUMINS AT DIFFERENT pH VALUES

Parvalbumins of herring (Clupea harengus) and carp (Cyprinus carpio) are essential components of the pattern ofsarcoplasmic proteins used for fish species identification by isolelectric focusing. In fishery products oflowpH, like marinated herring (pH ～ 4), parvalbumins were not detectable. It was demonstrated for herring and carp that parvalbumins were not precipitated at pH 4, but were degraded by fish muscle proteases.     

Cloud detection and classification over oceans at night with NOAA-7

Clouds above the ocean are detected with three thermal-infrared channels of the AVHRR on board NOAA-7. A classification into low, middle and high clouds is possible. As only spectral and not spatial information is used, it is possible to analyse each pixel individually. The classification has been developed with a radiative transfer model for clouds adapted to the spectral domain of the NOAA-7 infrared channels. The ruling parameter is the ratio between scattering and extinction. The spectral optical depth has slightly less influence, while different anisotrophy of scattering for individual types of clouds is not important. Two parameters are best suited to classifying clouds, namely, brightness temperature in channel 5(12·0 μm) and the difference of brightness temperature between channel 3 (3·7μm) and channel 4 (10·8 μm). The algorithm to classify clouds with thresholds referring to the standard atmosphere ‘autumn 45° north’ is applied to actual satellite data.     

Solid Solubility of Na2O in Mullite

Incorporation of up to 0.4 wt% Na₂O was found in the mullites of fused-cast mullite brick. Sodium oxide incorporation probably requires very high temperatures and persists only when the material is quenched rapidly to room temperature; it may be stabilized by simultaneous entry ofZr⁴⁺ into the mullite structure.     

Shelf life of ice-stored redfish, Sebastes marinus and S. mentella

Redfish ( Sebastes marinus and S. mentella ) were caught by an Icelandic trawler, stored at about 0°C in boxes in the hold and landed in a German fishing harbour. Boxed redfish, differing in storage time on board, were subsequently stored in melting ice in the chill store of the laboratory at a temperature of +4°C until the borderline of saleability was reached. the quality loss of the ice-stored redfish was monitored by a number of chemical, physical and microbiological parameters including volatile base nitrogen (TVB-N), trimethylamine (TMA), trimethylamine oxide (TMAO), creatine, ethanol, Fishtester readings and number of cfu. AH parameters were correlated with sensory analysis and time in ice.
The rate of deterioration of iced redfish depended on the conditions of storage. Sensory analysis was the most accurate indicator of the limit of saleability of redfish. Iced redfish, stored mainly in a chill store (4–5°C) onshore, had a shelf-life of 16 to 19 days from catching. Fish stored at 0.5°C in the hold of the fishing vessel had a shelf-life of 22 days: These results reflect the different storage temperatures and the effects of handling, transport and storage damage on the quality of the fish. the Fishtester proved to be very useful for the determination of deterioration. Measuring ethanol, TVB-N and TMA gave no information about quality changes during the first 12 days of storage.     

Remote sensing of coastal waters by airborne lidar and satellite radiometer Part 1: A model study

Abstract

Radiative transfer calculations for remote sensing of coastal waters by airborne lidar and satellite radiometer have been compared in order to answer the question, whether an airborne lidar may be used instead of in situ measurements from ships to calibrate a satellite radiometer. The radiative transfer of laserlight measuring the Raman-scattering of water molecules, the fluorescence of chlorophyll-a and the fluorescence of yellow substance or Gelbstoff is simulated by the lidar equations while the radiance to a satellite radiometer is calculated with an ocean-atmosphere model based on the matrix-operator method. Including multiple scattering in the lidar equations, an eigenvalue analysis shows that three oceanic constituents (chlorophyll-a, nonchlorophyllous particles and Gelbstoff) can be separated measuring the backscattered laserlight at three wavelengths from a height of 100 to 200m. Changes in the concentration of all three substances are detected with higher accuracy with an airborne lidar than with a radiometer even at the same height. A comparison of different algorithms indicates that the common blue-green algorithms fail in coastal waters due to the variability of several oceanic constituents, which influence the colour of sea water. In this case, algorithms using the sun-induced chlorophyll-a fluorescence at 685 nm, are superior to blue-green algorithms. Airborne lidar measurements of the chlorophyll-a fluorescence at 685 nm, normalized by the Raman-signal at 650 nm, are as good as in situ data and can be used to calibrate satellite measurements of chlorophyll-a.