Das Ergebnis der Wassergehaltsbestimmung von Butter in Abh?ngigkeit von der Arbeitsweise mit und ohne Verteilungsmitteln

Zusammenfassung Die Frage, ob Natriumchlorid allgemein — und welcher Reinheitsgrad der geprüften 5 Salzsorten im besonderen — geeignet sei, bei der gravimetrischen Butterwasserbestimmung (Trockenschrankmethode) das üblicherweise verwendete Ver teilungsmittel Seesand mit Vorteil zu ersetzen, bzw. ob unter Umständen bei dieser Arbeitsweise — vergleichsweise zur Schnellmethode — ebenfalls auf ein Verteilungsmittel verzichtet werden kann, wurde durch statistisch ausgewertete Vergleichsuntersuchungen beantwortet.Es ergab sich, daß die geprüften Salze: Natriumehlorid zur Analyse a) — reinst, getrocknet, fein gepulvert b) — reinst, getrocknet c) — reinst, kristallisiert DAB. 6. d) sowohl im Hinblick auf die Genauigkeit der Arbeitsweise, als auch in bezug auf die statistisch gesicherte Gleichartigkeit der Ergebnisse, ferner hinsichtlich der Troeknungszeit dem Verteilungsmittel Seesandgleichwertig sind. Diese Feststellung trifft bei Verwendung eines Kochsalzes mit nicht definiertem Reinheitsgrad [Salz e)] nurmehr beschränkt zu: Trotz ausreichender Genauigkeit ergibt sich bei dessen Verwendung ein niedrigerer Wassergehalt der Butter als mit Seesand, eine Unterschiedlichkeit, die statistisch gesichert ist. Auch eine vergleichsweise fast doppelt so lange Trocknungsdauer spricht gegen dessen Verwendung.Welchem von den geeigneten Salzen der Vorzug einzuräumen ist, kann nur bei gegenseitiger Abwägung verschiedener Faktoren entschieden werden:Nicht erforderlich ist es, sich einseitig auf die Verwendung von Natriumchlorid mit dem höchsten Reinheitsgrad; NaCl pro anal., festzulegen, vielmehr scheint in bezug auf Genauigkeit, Gleichartigkeit, Troeknungszeitund Preis das Natriumchlorid reinst, getrocknet, fein gepulvert b) das Salz derWahl zu sein.Bei der gravimetrischen Methode (Trocknung in einstündigen Intervallen bei 103–105°C im Trockenschrank bis zur Gewichtskonstanz) ist der Arbeitsweise mit Verteilungsmitteln gegenüber der Arbeitsweise ohne Verteilungsmitteln in bezug auf Genauigkeit und Zeitaufwand der Vorzug zu geben.Die Notwendigkeit eines Verreibens der Butter mit dem Verteilungsmittel besteht bei der Wasserbestimmungnicht, vielmehr erwies sich — vergleichsweise dazu — die Arbeitsweise des Nichtverreibens im Hinblick auf die Genauigkeit und Zeitdauer der Bestimmunggleichwertig, arbeitstechnisch gesehen aber überlegen.     

Piecewise linear optimization: Duality and numerical results

The dual of an optimization problem with piecewise linear, convex, and continous objective function and linear restrictions is investigated. It is shown that the dual problem is of the same type as the primal and can be solved by the same methods as were proposed in a previous work of the author. Experiences arising from the application of different variants of these methods to solve a number of examples, where the primal as well as the dual version was employed, are reported.     

Inhibition of GABA metabolism in rat brain slices by halothane

Based on studies with rat cerebral cortex slices, it was previously hypothesized that halothane anesthesia may result from increased GABA (gamma-aminobutyric acid) content in the synapses. Since GABA is an inhibitory neurotransmitter, such increases may cause a reduction in synaptic activity. The increase in GABA content could arise from several possible causes which are examined in this study using rat cerebral cortex slices as a model. The effects of halothane on uptake, release, and catabolism of GABA were determined. Uptake was studied by the amounts of radioactive GABA accumulated by the slices, and release studied by that discharged into the medium from slices preloaded with radioactive GABA. Catabolism was assessed by preloading the slices with radioactive GABA and then followed by measuring the amount of radioactivity found in unmetabolized GABA or in pooled GABA metabolites. Since CO2 was established as a major metabolite, it was subsequently used alone to measure the inhibition of GABA catabolism in the presence of varying amounts of halothane. Halothane (3 per cent) did not affect the high-affinity uptake or the release of GABA but did inhibit the catabolism of GABA. Using 14CO2 production as an index of catabolism, the inhibition of GABA catabolism by halothane was dose-related (8.79 per cent inhibition/per cent halothane). Such results support the hypothesis that halothane anesthesia may result at least in part from an inhibition of GABA catabolism which, in turn, causes increased GABA level in the synapse with resultant synaptic inhibition.     

Thin films of the organic superconductor α-(BEDT-TTF)2I3

α-(BEDT-TTF)₂I₃ is a quasi-two-dimensiona1 organic metal with a metal-insulator phase transition at 135 K. Thermal treatment at about 80°C leads to the metallic system α₁-(BEDT-TTF)₂I₃ which becomes superconducting below 8 K. Thin films of the α-phase (between 500 and 3000 A thick) have been evaporated in high vacuum onto several substrates and characterised by means of X-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM) and a low field microwave absorption technique. Depending on the temperature of the substrate and the evaporation rate, the films exhibit different degrees of microcristallinity, which under certain conditions can be strongly reduced and a completely covering film can be obtained. X-ray diffraction spectra reveal a high orientation with the c-axis perpendicular to the substrate and as well the successful conversion into the α₁- phase by tempering. SEM and AFM investigations prove that the conversion takes place without reducing the mechanical quality of the films. Low-field microwave-absorption experiments show that the α₁-films become superconducting with an onset at 9 K.     

Divertor IR thermography on Alcator C-Mod

Alcator C-Mod is a particularly challenging environment for thermography. It presents issues that will similarly face ITER, including low-emissivity metal targets, low-Z surface films, and closed divertor geometry. In order to make measurements of the incident divertor heat flux using IR thermography, the C-Mod divertor has been modified and instrumented. A 6° toroidal sector has been given a 2° toroidal ramp in order to eliminate magnetic field-line shadowing by imperfectly aligned divertor tiles. This sector is viewed from above by a toroidally displaced IR camera and is instrumented with thermocouples and calorimeters. The camera provides time histories of surface temperatures that are used to compute incident heat-flux profiles. The camera sensitivity is calibrated in situ using the embedded thermocouples, thus correcting for changes and nonuniformities in surface emissivity due to surface coatings.     

Determination of the geographical origin of processed spice using multielement and isotopic pattern on the example of Szegedi paprika

This case study presents a fast and reliable method of combining strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) with a multielement pattern (Rb, Sr, Y, Zr, Mo, Cd, Ba, Pb, Th, U, Mg, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and rare earth elements) by means of inductively coupled plasma mass spectrometry (ICP-MS) to establish a unique fingerprint of authentic Szegedi Fűszerpaprika (PDO) and classify authentic and purchased paprika from different known, declared and unknown geographical origin using multivariate statistical tools (principal component and canonical discriminant analysis). Since paprika represents a processed spice, alterations in element and Sr isotopic composition throughout the production process were investigated. The Sr source in the final product was identified to stem from bioavailable Sr sources in soil. Therefore, the ammonium nitrate extract of a soil is sufficient to establish a Sr fingerprint for agricultural products of a region. As a consequence, the spice paprika can be traced back to its geographical origin even after processing.     

Flooding of municipal solid waste landfills — An environmental hazard?

Municipal solid waste (MSW) landfills pose a long-lasting risk for humans and the environment. While landfill emissions under regular operating conditions are well investigated, landfill behaviour and associated emissions in case of flooding are widely unknown, although damages have been documented. This paper aims at developing a methodology for determining the proportion of MSW landfills endangered by flooding, and at evaluating the impact flooded landfills might have on the environment during a flood event.The risk of flooding of MSW landfills is assessed by using information about flood risk zones. Out of 1064 landfills investigated in Austria, 312 sites or about 30% are located in or next to areas flooded on average once in 200 years. Around 5% of these landfills are equipped with flood protection facilities. Material inventories of 147 landfill sites endangered by flooding are established, and potential emissions during a flood event are estimated by assuming the worst case of complete landfill leaching and erosion. The environmental relevance of emissions during flooding is discussed on the basis of a case study in the western part of Austria. Although environmental hazards need to be assessed on a site- and event-specific basis, the results indicate that flooded MSW landfills represent in general small environmental risks for the period of flooding. The longer term consequences of flooding are discussed in a next paper.     

In vitro cytotoxicity of oxide nanoparticles: comparison to asbestos, silica, and the effect of particle solubility

Early indicators for nanoparticle-derived adverse health effects should provide a relative measure for cytotoxicity of nanomaterials in comparison to existing toxicological data. We have therefore evaluated a human mesothelioma and a rodent fibroblast cell line for in vitro cytotoxicity tests using seven industrially important nanoparticles. Their response in terms of metabolic activity and cell proliferation of cultures exposed to 0-30 ppm nanoparticles (microg g(-1)) was compared to the effects of nontoxic amorphous silica and toxic crocidolite asbestos. Solubility was found to strongly influence the cytotoxic response. The results further revealed a nanoparticle-specific cytotoxic mechanism for uncoated iron oxide and partial detoxification or recovery after treatment with zirconia, ceria, or titania. While in vitro experiments may never replace in vivo studies, the relatively simple cytotoxic tests provide a readily available pre-screening method.