Enhanced drag in pipe turbulent flow by an aqueous electrolyte: an electroviscous effect

Drag enhancement is reported for turbulent pipe flow of aqueous electrolyte solutions. No electroviscous effect was obtained with laminar flow. Nor was any unusual pressure drop observed for laminar or turbulent flow of non-electrolyte aqueous solutions such as sugar. An electroviscous theory was advanced that predicted the drag enhancement for a 1/1 electrolyte solution. The theory depended on consideration of Debye length

The influence of dimethyl sulphide and carbon disulphide in the bouquet of wines

Sensory evaluation of DMS added to wines at very low concentrations has shown that addition of 0.022 μl · l-1 resulted in statistically more favoured wines than those with no, or 0.044 μl · l-1 added DMS. This shows that low concentrations of DMS can have a beneficial effect on the quality of some wines.The concentration of CS2 necessary to give any sensory response was higher than that observed in any commercial wine.The threshold of smell for DMS in distilled water was found tobe 7.5 x 10-5 μl · l-1 (0.08 ppb) while that for taste was 4 x 10-4 μl · l-1 (0.4 ppb).Der Einfluß von Dimethylsulfid und Schwefelkohlenstoff auf das WeinaromaBei der sensorischen Beurteilung von Weinen, denen Dimethylsulfid in sehr niedrigen Konzentrationen zugesetzt worden war, wurden jene mit 0,022 μl · l-1 vor solchen ohne oder mit 0,044 μl · l-1 Dimethylsulfid bevorzugt. Geringe DMS-Mengen können demnach die Weinqualität positiv beeinflussen.Die sensorisch wahrnehmbare Schwefelkohlenstoffkonzentration war höher als die in den Weinen gefundenen Mengen.Der Geruchsschwellenwert für Dimethylsulfid in Aqua dest. betrug 7,5 x 10-5 μl · l-1, der Geschmacksschwellenwert dagegen 4 x 10-4 μl· l-1

Preparation of rare earth metals

The production of over 400 grams of pure gadolinium metal by reduction of the anhydrous chloride by calcium in tantalum vessels is described; yields were over 97%. The use of the same techniques in an attempt to prepare yttrium metal were partially successful

Uptake and metabolism of 35S-sulphate by wine yeast

The 35S-labelled metabolites obtained by growing three strains of wine yeast in a medium with 35S-sulphate as the sole source of sulphur were methionine, cystine, cystathionine, glutathione and S-adenosylmethionine. Two further compounds were separated and thought to be adducts of sulphite associated non-metabolically with cell wall components.The yeast strains were chosen to represent high sulphide formation, high sulphite formation and a combination of low sulphite and sulphide formation. Comparison of the relative 35S activities of the compounds formed by each strain suggested that sulphide production could be explained in terms of a lowered rate of synthesis of methionine and its activated metabolites leading to lowered control over the production of sulphite reductase. Lowered SAM and methionine production allowing derepression of ATP sulphurylase, together with the reported low activity of sulphite reductase in sulphite producing yeast, could be an explanation for sulphite production.Aufnahme und Umsetzung von 35S-Sulfat durch WeinhefenNach Vergärung eines Substrates mit 35S-Sulfat als einziger Schwefelquelle durch drei Weinhefenstämme - viel H2S, viel SO2 und sowohl wenig H2S als auch SO2 bildend - waren folgende Stoffwechselprodukte radioaktiv markiert: Methionin, Cystin, Cystathionin, Glutathion und S-Adenosylmethionin {SAM). Zwei weitere nicht identifizierte Komponenten könnten Anlagerungsprodukte von Sulfit mit Zellwandkomponenten darstellen.Aus der relativen 35S-Aktivität der Stoffwechselprodukte bei den verschiedenen Hefestämmen kann auf eine verminderte Synthese von Methionin und seinen Metaboliten geschlossen werden. Die möglichen Auswirkungen auf die H2S- und SO2- Bildung werden diskutiert

Origin and significance of 'dispersed facies' basal ice: Svínafellsjökull, Iceland

Dispersed facies basal ice - massive (i.e. structureless) ice with dispersed debris aggregates - is present at the margins of many glaciers and, as a product of internal glacial processes, has the potential to provide important information about the mechanisms of glacier flow and the nature of the subglacial environment. The origin of dispersed facies is poorly understood, with several hypotheses having been advanced for its formation, and there is disagreement as to whether it is largely a sedimentary or a tectonic feature. We test these established hypotheses at the temperate glacier Svfnafellsjokull, Iceland, and find that none fully account for dispersed facies characteristics at this location. Instead, dispersed facies physical, sedimentological and stable-isotope (5180, 8D) characteristics favour a predominantly tectonic origin that we suggest comprises the regelation and straininduced metamorphism of debris-rich basal ice that has been entrained into an englacial position by tectonic processes operating at the base of an icefall. Further thickening of the resultant dispersed facies may also occur tectonically as a result of ice flow against the reverse bed slope of a terminal overdeepening. Lack of efficient subglacial drainage in the region of the overdeepening may limit basal melting and thus favour basal ice preservation, including the preservation of dispersed facies. Despite the relatively low sediment content of dispersed facies (~1.6% by volume), its thickness (up to 25 m) and ubiquity at Svfnafellsjokull results in a significant contribution to annual sediment discharge (1635-3270 m3 a"1) that is ~6.5 times that contributed by debris-rich stratified facies basal ice

The distribution of dimethyl sulphide in some New Zealand wines

All New Zealand experimental wines of the vintages 1975-1980 tested showed the presence of DMS in at least one vintage year, whether the wines were red or white. There was a general trend for older wines to have a higher probability for the presence of DMS than younger wines. The variability in the presence of DMS was suggested to be related to the processing of the wines. Dimethyl sulphoxide seems to be the precursor of DMS formed during bottle aging.Carbonyl sulphide found in grape juices was thought to be lost during fermentation because of its high volatility.Über das Vorkommen von Dimethylsulfid in einigen neuseeländischen WeinenVon allen auf das Vorkommen von Dimethylsulfirl (DMS) untersuchten neuseeländischen weißen und roten Versuchsweinen der Jahrgänge 1975-1980 zeigte zumindest ein Jahrgang die Anwesenheit dieser Aromakomponente. Ältere Weine scheinen ganz allgemein häufiger DMS zu enthalten als junge. Es wird vermutet, daß die hohe Streubreite von der Weinbereitung abhängt. Dimethylsulfoxid scheint die Vorstufe von DMS zu sein, das während des Alterungsprozesses auf der Flasche entstehen könnte.In einigen Mosten wurde Carbonylsulfid nachgewiesen, das jedoch wegen seiner hohen Flüchtigkeit mit dem Gärgas entweichen dürfte

Energy requirements of a thermally processed ISRU radiation shield for a lunar habitat

The purpose of this study was to establish, on a first principles basis, the order of magnitude of energy requirements for a thermally processed, lunar regolith radiation shield constructed using an in-situ resource utilisation (ISRU) approach. This was done by developing a reference scenario habitat and using thermodynamic relationships and specific heat capacity expressions to determine the energy required to bring such a regolith volume up to sintering temperatures (c. 1375 K). Once the energy requirements were developed some power system architectures were outlined conceptually and a nuclear power plant of c. 400 kW was suggested as a means to supply the necessary energy. This is well beyond current space nuclear applications. The study concludes that it is likely that the most efficient near-term solution is chemical processing of regolith, from an energy requirements perspective. The technology is also more mature and likely to be delivered on near term projects as it does not require such scaled-up power system architectures. Alternatively, bringing storm shelters up with the habitat to provide a means of weathering major solar events, and adding additional radiation protection to habitat quarters, possibly through a water blanket or similar mechanism, could provide a non-ISRU solution with current technology. However, in the longer term, the development of MW-scale reactors or other power system architectures may permit a very large volume of material to be processed thermally for both construction material and volatile extraction, making a large, permanent human presence on the Moon more easily realisable

The ferromagnetic properties of the rare earth metals

The magnetic moment of gadolinium was measured in applied fields of 4,000-18,000 oersteds, and over the temperature range of 20.4°K to 320°K

The separation of rare earths by ion exchange. IV. Further investigations concerning variables involved in the separation of samarium, neodynium and praseodymium

Previous papers of this series have dealt with some of the variables concerned with the separation of rare earths by means of ion exchange. It has been apparent from the first that the many variables involved should be investigated more thoroughly in order to improve the degree of separation of certain pairs of the rare earths. It was decided, therefore, to study further the effect of such variables as temperature, pH of eluant, size of resin particles and flow rate

The formation of volatile sulphur compounds in unclarified grape juice

The evolution of the sulphur gases OCS, CS2 and DMS was monitored during the clarification of freshly harvested juices from Müller-Turgau and Riesling. Immediately after crushing OCS and CS2 levels began to increase, substantially favoured by high temperatures. When fermentation started concentrations decreased. DMS was found only in fermenting juices