X-ray phase-contrast tomography of porcine fat and rind

X-ray computed tomography (CT) has recently received increased attention in the food science community. The aim of this paper is to demonstrate how grating based phase-contrast CT can provide contrast superior to standard absorption based CT. The method of phase-contrast CT is applied to two samples of porcine subcutaneous fat and rind. The additional contrast obtained may be used for quality testing, to investigate variations in fatty acid composition of the fat-fraction, and density variations in the meat-fraction. The possibility of integrating the method into an abattoir environment is discussed.     

Monitoring of metallic micronutrients and heavy metals in herbs,spices and medicinal plants from Austria.

Medicinal, aromatic and spice plants grown in different regions of Austria were monitored as to their Cd, Cu, Fe, Mn, Pb and Zn contents. Since the plants were grown under common field conditions, the essential elements were within the usual ranges for plant material. The contamination level with the toxic heavy metals, Pb and Cd, can be classified as normally low. Most samples contained less than 0.2 mg kg^у Cd and less than 1.5 mg kg^у Pb on a dry weight basis. Comparison with previous investigations suggests that contaminations with Pb occur rather by chance, whereas enhanced Cd values are restricted to some species having a tendency to accumulate this heavy metal. Some such species are St. John´s wort, poppy, yarrow, chamomile and absinth. Careful choice of growing site and appropriate soil management can reduce the Cd uptake of these critical species. These precautions are important when larger amounts of the product are consumed.     

Measurement of emissions from air pollution sources. 4. C1-C27 organic compounds from cooking with seed oils

The emission rates of gas-phase, semivolatile, and particle-phase organic compounds ranging in carbon number from C1 to C27 were measured from institutional-scale food cooking operations that employ seed oils. Two cooking methods and three types of seed oils were examined: vegetables stir-fried in soybean oil, vegetables stir-fried in canola oil, and potatoes deep fried in hydrogenated soybean oil. The emission rates of 99 organic compounds were quantified, and these include n-alkanes, branched alkanes, alkenes, n-alkanoic acids, n-alkenoic acids, carbonyls, aromatics, polycyclic aromatic hydrocarbons (PAH), and lactones. Carbonyls and fatty acids (n-alkanoic and n-alkenoic acids) make up a significant portion of the organic compounds emitted from all three seed oil cooking procedures. The compositional differences in the organic compound emissions between the different cooking operations are consistent with the differences in the organic composition of the various cooking oils used. The distribution of the n-alkanoic acids between the gas and particle phases was found to be in good agreement with gas/particle partitioning theory. The relative importance of emissions from commercial deep frying operations to the total emissions of C16 and C18 n-alkanoic acids in the Los Angeles urban area was estimated using the available information and is estimated to account for approximately 7% of the total primary emissions of these acids. Additional emissions of these n-alkanoic acids from stir-frying and grill frying operations are expected. Estimates also indicate that seed oil cooking may make up a significant fraction of the emissions of lighter n-alkanoic acids such as nonanoic acid.     

Thermodynamic Activities in B2O3-SiO2 Melts at 1475 K

Eight glass samples in the B₂O₃-SiO₂ system with compositions from 20 to 90 mol% B₂O₃ were prepared. The equilibrium vaporization was studied by Knudsen effusion mass spectrometry at temperatures between 1450 and 1500 K. B₂O₃ ( g ) was the most abundant boron-containing species in the vapor; no silicon-containing gaseous species were detected. Thermodynamic activities of B₂O₃ in the liquid were determined at 1475 K. Thermodynamic activities of SiO₂ and integral excess Gibbs energies were estimated from the thermodynamic activities of B₂O₃. The thermodynamic data support the results obtained by other methods indicating the existance of a miscibility gap in the metastable liquid.     

Studies on the development of a quick inertness test procedure for multi-use PET containers—sorption behaviour of bottle wall strips

This study is part of a larger project aimed at establishing criteria to ensure the quality and safety-in-use of recycled and re-used plastics for food packaging. A major concern is that plastic materials can interact with chemicals to a greater or lesser extent. As a consequence, refillable containers may be contaminated by migration of harmful substances into the plastic material due to misuse by consumers before return. On the other hand, there is currently neither any specific national or EU regulation nor a standard test available which could be applied by industry or enforcement laboratories to meet this situation appropriately. In this study, a relative simple inertness test which focuses on the interaction of PET bottle wall strips with a selection of model contaminants was investigated. The model contaminants were selected to include four different sets of chemical functional classes (set A, alcohol-type compounds; B, ester/ketone type compounds; set C, hydrocarbon-type compounds; set D, chlorinated hydrocarbons). A simple gas chromatographic method using flame ionization detection was developed to allow quantification of the whole range of model contaminants. Linearity and reproducibility of the calibration curves for all contaminants were excellent, which indicates the validity and efficacy of the proposed methodology. The sorption experiments with PET bottle wall strips showed that significant amounts of chemicals can be absorbed into the plastic material if misused, thus establishing a remigration potential in the bottle material after refilling. © 1997 John Wiley & Sons, Ltd.     

Optical roughness measurements with fringe projection

The characterization of roughness of engineering surfaces over an area is an important task for different applications as well as for manufacturing processes. The surface roughness is in particular an important factor in determining the performance of a workpiece. We demonstrate that the fringe projection technique allows very fast three-dimensional surface inspections. The inspection time for an entire measurement is reduced to less than 5 s with standard hardware. Based on a zoom stereo microscope setup, we demonstrate a modular measuring instrument. The magnification-dependent vertical resolution can be as high as 0.1 microm. The special properties for roughness measurements are demonstrated, especially the comparability with a tactile sensor and with other optical sensors, which is discussed in connection with amplitude parameters.     

Development of superconducting absorbers for CRESST light detectors

An important aspect of dark matter search experiments is the active background reduction by identification of the type of particle interacting in the detector. In CRESST this is achieved by a simultaneous detection of heat and light produced by an interaction in a scintillating crystal. The overall light collection efficiency is a crucial parameter in order to achieve enough sensitivity to measure the small fraction of the deposited energy that is emitted as scintillation light. For this purpose, a thin superconducting lead film deposited on sapphire substrates has been tested as an alternative light absorber to a silicon absorber. The first results already show a better light absorption of the lead film. Other superconducting films are also being analyzed.     

Ebene Kerbspannungen in viskoelastischen Werkstoffen

Zusammenfassung Die Gleichungen des ebenen elastischen Spannungszustands werden durch Spezialisieren aus der dreidimensionalen Theorie hergeleitet. Bei reinen Spannungsrandbedingungen h?ngen die Spannungen nur von der Belastung und der Geometrie des untersuchten K?rpers, nicht aber von den elastischen Konstanten und damit auch nicht von den jeweiligen Werkstoff ab. Die Gültigkeit dieses bekannten Ergebnisses wird auf viskoelastische Werkstoffe mit Hilfe der von E. H. Lee formulierten viskoelastisch-elastischen Analogie ausgedehnt. Die technische Anwendbarkeit der Ergebnisse auf ebene Kerbspannungsprobleme in hochpolymeren Kunststoffen geht aus einem Beispiel hervor. Der Verfasser widmet diesen Aufsatz Herrn Prof. Dr. rer. nat. h. c. LL. D. h. c. Dr.-Ing.Ernst Schmidt zur Vollendung seines 75. Lebensjahres.