The recovery of sodium chloride from sea water     

Rudolf C. Leutz 《International Journal of Mineral Processing》1974,1(2):163-171

The recovery of sodium chloride from the sea has been practised since ancient times. Modern knowledge of phase rules enables us to recover fairly clean sodium chloride from sea water, which consists of a complex mixture of salts and other minerals. According to quality requirements, two procedures can be applied; solar pre-concentration of the sea water with subsequent vacuum distillation, or solar pre-concentration with subsequent over-saturation and precipitation of the salt. The individual product requirements and cost factors have to be diligently studied in order to decide which procedure is the more feasible.  相似文献   

Semantic Interoperability through the Definition of Conceptual Model Transformations     

Peter Staub  Hans Rudolf Gnägi  Andreas Morf 《Transactions in GIS》2008,12(2):193-207

The integration of distributed geospatial data is a great issue in GI Science. Hereby, the collection of data from different systems and different structures as well as across country borders is a problem. We explain a model‐based four‐step approach to conceptual data modelling. Within this approach, we introduce a methodology to map data models on the conceptual level without touching data formats. First, we developed a conceptual mapping language called “UMLT” which is the core of our approach. Furthermore, we integrated UMLT into the Model‐Driven Architecture where a conceptual model mapping is referred to as a platform independent model mapping. Finally, the data format transformation is deduced from the model mapping automatically. This represents the implementation mapping from a platform independent model to a platform specific model. Together with transformation operations for attribute mapping, this approach is a means for effective and enhanced semantic interoperability.  相似文献   

A large skull of Ichthyosaurus (Reptilia: Ichthyosauria) from the Lower Sinemurian (Lower Jurassic) of Frick (NW Switzerland)     

Michael W. Maisch  Achim G. Reisdorf  Rudolf Schlatter  Andreas Wetzel 《Swiss Journal of Geoscience》2008,101(3):617-627

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Groundwater fluctuations and footslope ferricrete soils in the humid tropical zone of southern Cameroon     

Emile Temgoua  Henri‐Bosko Djeuda Tchapnga  Emile Tanawa  Claire Guenat  Hans‐Rudolf Pfeifer 《水文研究》2005,19(16):3097-3111

This paper discusses the relationship between the differentiation of ferruginous accumulations and the variable water saturation of footslope soil patterns. An analysis of the slope morphology of a typical hill in the forest zone of southern Cameroon and a seasonal survey of the levels of groundwaters, springs and rivers were considered in relation to the petrology of different soil patterns. The study site is a tabular hillock whose slopes present a progressive development from steep to gentle slopes. The variable residence time of water within the soil, creating an alternation of reducing and oxidizing conditions, affects soil chemistry, structure and lateral extension of the soil patterns. The ferruginous soil patterns, being formed on the footslopes, gradually increase in extent with decreasing slope angle and the relative rise of the groundwater level. The steep footslopes, where groundwater has a shorter residence time, show a soft mottled clay pattern, restricted to the bottom part of the slope. The moderate footslopes exhibit a deep permanent and a temporary perched groundwater table. The latter, with its regular capillary fringe, contributes to more reducing conditions within isolated domains in the soil patterns, and thus to the alternation with oxidizing conditions, generating a continuous hard soil pattern (massive carapace). The more gently dipping footslopes exhibit groundwater levels near the surface and also a significant amplitude of groundwater fluctuation. Iron, previously accumulated in moderate footslope patterns, is reduced, remobilized, and leached. The soil patterns formed develop into a variegated carapace, more extended along the slope, containing less iron, but nevertheless more hardened, due to the important fluctuations of the groundwater table. These patterns are limited to the zone of groundwater fluctuation and deteriorate as the water fluctuation zone recedes. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Editorial for the VEESD 2013 special issue     

Christoph Adam  Rudolf Heuer 《Bulletin of Earthquake Engineering》2015,13(4):953-955

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Field validation, in Scotland and Iceland, of the artificial mussel for monitoring trace metals in temperate seas     

Leung KM  Furness RW  Svavarsson J  Lau TC  Wu RS 《Marine pollution bulletin》2008,57(6-12):790-800

The artificial mussel (AM), a novel chemical sampling device, has been developed for monitoring dissolved trace metals in marine environments. The AM consists of Chelex-100 suspended in artificial seawater within Perspex tubing and enclosed with semi-permeable polyacrylamide gel at both ends. To validate the field performance of the AM in temperate waters, we deployed AMs alongside transplanted blue mussels Mytilus edulis in coastal environments in Scotland (Holy Loch, Loch Fyne, Loch Striven and Millport) and Iceland (Reykjavikurh?fn, Gufunes, South of thornerney, Hofsvik, Hvalfj?rethur and Sandgerethi) for monitoring trace metals. While uptake patterns of Cd between the AM and M. edulis were highly comparable, discrepancies were found in the accumulation profiles of the other metals (Cu, Cr, Pb and Zn), in particular Zn. Nonetheless, the AMs gave a better resolution to accurately reveal the spatial difference in dissolved metal contamination when compared with M. edulis. AMs complement the use of mussels since AMs indicate dissolved metals in seawater, whereas uptake by mussels indicates a mixture of dissolved and particulate metals. Our results also indicated that historical metal exposure of the transplanted M. edulis could significantly confound their metal concentrations especially when the deployment period was short (i.e. <34d). This study suggested that the AM can overcome problems associated with variable biological attributes and pre-exposure history in the mussel, and provides a standardized and representative time-integrated estimate of dissolved metal concentrations in different marine environments.  相似文献   

Zur Frage des Kontinental-Effektes derF2-Schicht     

Rudolf Eyfrig 《Pure and Applied Geophysics》1959,44(1):179-187

Zusammenfassung Messwerte russischer Stationen beweisen die Existenz eines «Kontinental-Effektes» bei der maximalen Elektronendichte derF2-Schicht. Im Sommer besteht im Innern des asiatischen Kontinents vorzugsweise eine höhere Konzentration bei Tag; andererseits fehlt dort die sogenannte «Abend-Konzentration».

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Summary Results from Russian stations prove the existence of a «Continental effect», on the Maximum electron density of theF2-layer. In summer, in the interior of the asiatic continent a tendency exists for a higher concentration in daytime; on the other side the so-called «evening concentration» is missing there.

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HerrnJulius Bartels zum sechzigsten Geburtstag gewidmet.  相似文献   

Hypoxia: from molecular responses to ecosystem responses   总被引：24，自引：0，他引：24  

Wu RS 《Marine pollution bulletin》2002,45(1-12):35-45

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Auswirkungen von Temperaturerhöhungen in Gewässern     

G. Rudolf 《洁净——土壤、空气、水》1973,1(4):381-385

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Third Body Perturbations of Double Stars     

Rudolf Dvorak 《Celestial Mechanics and Dynamical Astronomy》1997,68(1):63-73

We report on the different results concerning the stability of the hierarchical triple systems where a close binary is accompanied by a third star. There are different possible approaches to answer the question of the stability limits for such triple stars: the most direct investigations can be undertaken in integrating numerically the respective equations of motion for many different initial conditions. It is then difficult to take into account all the important parameters like eccentricities, inclination, phases and masses. Analytical approaches and qualitative methods are more approriate to deal with this problem; the respective results confirm the numerically found results that: 1. for prograde orbits the ratio semimajor axis of the inner orbits to the periastron position of the outer orbit is approximately 3.2 2. for retrograde orbits this ratio is just some 10 percents smaller 3. the results are not sensitive in what concerns the masses involved 4. There is a tendency that the inclinations and eccentricities change slightly the stability limits mentioned above. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献