The influence of natural organic matter on the adsorption properties of mineral particles in lake water

The adsorption characteristics of sediment particles from a prealpine Swiss lake were compared with those of γ-aluminum oxide. Under lake water conditions, i.e. with particle concentration of 2–16 mg/1 and DOC concentrations of 1–4 mg/1 at pH=8, the adsorption of copper, zinc and orthophosphate is reduced significantly by the presence of natural organic matter (NOM). It is postulated that the binding sites of the natural mineral surfaces are occupied almost completely by NOM under natural conditions. A simple ligand exchange model can explain the observed phenomena.     

Enhancing mobile applications by combination of GNSS and W-CDMA

The location requirements for emergency callers outside urban areas can hardly be fulfilled without global navigation satellite systems (GNSS). Consequently, interest in positioning techniques based on use of a GNSS such as GPS or on the cellular network infrastructure itself is growing rapidly in the mobile-telephone community. Moreover, the increasing demand for commercial location-based services (LBS) has driven cellular-phone and network manufacturers to focus on positioning solutions which are even more accurate than the regulatory mandates for positioning of emergency callers. One example of these upcoming LBS is our PARAMOUNT project, which aims at improving user-friendly info-mobility services for hikers and mountaineers by combining wireless communications (GMTS), satellite navigation (GNSS) and geographic information systems (GIS), based on a mobile client/server architecture. The availability of mobile phones or PDAs with combined GNSS and cellular network-based wireless communication on a high integration level is one primary demand of such LBS applications. Based on this, we will give some initial answers to the question of whether mobile handset architecture synergies exist for the combination of GNSS with wireless location in CDMA cellular wireless networks. In order to identify synergies, we will outline similarities and differences between wireless communication and satellite navigation. In this respect, we pay particular attention to the so-called RAKE receiver architecture employed in mobile CDMA cellular handsets. Our initial investigations will show that the RAKE receiver architecture, on which mobile CDMA cellular handsets are based, will most likely be the one most suitable for achieving synergies between the two positioning techniques within the same mobile handset architecture. Consequently, several receiver components could be used to handle both types of signals (navigation and communications), resulting in a reduction of manufacturing costs and in a decrease in energy consumption. Electronic Publication     

3. Einregelung naeh dem Periklingesetz „mit verminderter Symmetrie”.

Zusammenfassung Das Periklingesetz verlangt Spiegelsymmetrie in der Zone senkrecht [010]; die kristallographische Symmetrie wiederholt sich in der Lage der Indikatrizen. Die Einmessung zeigt aber, daß (trotz normaler Verwachsung nach dem rhombischen Schnitt) die Symmetrie der verzwillingten Indikatrizen verringert ist: die (theoretische)ZE fungiert nur als Halbierungsebene der korrespondierten Mittellinien, die volle Symmetrie wird nicht verwirklicht. In unserem Falle ist die eingelagerte Zwillingspartie in bezug auf dieZE korrekter orientiert als das Hauptindividuum. - Die Konstruktion derZE nachBEREK führt auch bei der verminderten Symmetrie der verzwillingten Indikatrizen zur Auffindung der morphologisch definierten Zwillingsachse. -Man wird eben nicht vergessen dürfen, daß die Zwillingsgesetze Idealformulierungen sind, denen die Wirklichkeit nicht immer gerecht wird.     

Was a dacite dome implicated in the 9,500 <Emphasis Type="SmallCaps">b.p.</Emphasis> collapse of Mt Ruapehu? A palaeomagnetic investigation

Constraining the process by which volcanoes become unstable is difficult. Several models have been proposed to explain the driving forces which cause volcanic edifices to catastrophically collapse. These include models for destabilisation of volcanic flanks by wedging due to dyke intrusion and the weakening of mechanical properties by pressurisation of pore fluids. It is not known which, if any, of the models are relevant to particular sector collapse events. Recent developments in the palaeomagnetic estimation of emplacement temperatures of volcaniclastic rocks have shown that even relatively low emplacement temperatures can be recorded by volcaniclastics with high fidelity. We have carried out a palaeomagnetic study of emplacement temperatures to investigate the role of igneous activity in the initiation of the 9,500 b.p. Murimotu sector collapse of Mt Ruapehu, New Zealand. This debris avalanche deposit has three fades which are stratigraphically superimposed, and the lowermost fades contains three lithological assemblages representing different segments of the edifice which were transported with little internal mixing within the flow. We have determined that some of the dacite-bearing assemblage 1, fades 1 was hot (∼350 °C) during transport and emplacement, whereas none of the other lithological assemblages of fades contained hot material. Our interpretation is that a dacite dome was active on the ancient Ruapehu edifice immediately prior to the Murimotu sector collapse. The partially cooled carapace of the dome and material shed from this part was incorporated into the avalanche deposit, along with cold lavas and volcaniclastics. We have not found evidence for incorporation of material at or close to magmatic temperatures, at least in the sampled locations. Our palaeomagnetic work allows us to develop a comprehensive, new palaeomagnetic classification of volcaniclastics. Published online: 25 January 2003 Editorial responsibility: D. Dingwell     

Monitoring of atmospheric deposition in European forests and an overview on its implication on forest condition

Forest conditions in Europe have been monitored over 20 years jointly by the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) and the European Union (EU). Maps for mean bulk SO₄, NO₃ and NH₄ deposition at around 400 intensive monitoring plots in the years 1999–2001, as well as time trends for the period 1996–2001, are presented. Mean bulk SO₄ deposition at 169 plots mostly located in central Europe decreased from 7.4 to 5.8 kgS ha⁻¹ a⁻¹. Mean NH₄ bulk deposition decreased from 6.2 to 5.3 kgN ha⁻¹ a⁻¹. Nitrate bulk deposition fluctuated around 5 kgN ha⁻¹ a⁻¹. On average, throughfall deposition was considerably higher than bulk deposition. Time trends for mean tree crown defoliation as an overall indicator for forest condition show a peak in the mid 1990s for most of the monitored main tree species and a recent increase for the years 2003 and 2004. Multivariate linear regression analyses show some significant relations between deposition and defoliation. These relations depend on the tree species and site characteristics. Effects of deposition are moderated by the influence of biotic stress factors such as insects and fungi and by abiotic stress factors, such as weather.     

Static load tests of driven concrete piles under CFRP confinement

ABSTRACT

This paper describes compressive static load tests of concrete driven piles confined by Carbon Fibre Reinforced Polymer (CFRP). The tested piles include one concrete pipe pile and one concrete rectangular pile which are all partially confined by CFRP, and other two piles with the same dimensions without CFRP application. Tests program was performed to obtain the behaviours of these composite piles. Four Static Loading Tests (SLTs) were conducted and the results shown that those two types of composite pile demonstrate less vertical displacement with the same loading of traditional concrete piles. Furthermore, the traditional methods of Load-settlement (Q-s) curves, Settlement-lg (Load) (s-lgQ) curves and Settlement-lg (Time) curves are analysed. Due to un-plunging condition, the interpretation methods of Davisson’s, DeBeers, Double-Tangent as well as Chin’s methods are demonstrated for the ultimate bearing capacity of these four piles. It is concluded that the CFRP confinement increased the ultimate bearing capacity and this composite material can be perfectly applied in geotechnical condition.     

Fidelity and time resolution of the magnetostratigraphic record in Siwalik sediments: high-resolution study of a complete polarity transition and evidence for cryptochrons in a Miocene fluviatile section

The Surai Khola section in southwest Nepal, a 5000 m continuously exposed record of fluvial sedimentation since Middle Miocene, was revisited for high-resolution magnetostratigraphy in sequences with expected cryptochrons and reversals of the geomagnetic field. Polarity intervals with durations of a few tens of thousands of years are recorded as zones of stable palaeomagnetic directions. Polarity transitions are recorded as zones with complex demagnetization behaviour of specimens in the sedimentary column. Almost antiparallel palaeoremanence directions, residing in different haematite phases in the same specimens, could generally not be separated properly by thermal demagnetization. Differing demagnetization paths for neighbouring specimens during a reversal suggest that measured transitional directions are not true geomagnetic field directions, but rather are generated by the superposition of variable amounts of at least two almost antiparallel components of magnetization. Accompanying studies of recent river sand deposits demonstrate that these sediments acquire a true depositional remanent magnetization (DRM) with considerable inclination errors and scattered directions for individual specimens.     

The Multiple Sources and Patterns of Methane inNorth Sea Waters

The methane concentration in the atmosphere andsurface water was surveyed along 58° N acrossthe North Sea. In addition, the vertical methanedistribution in the water column was determined at sixstations along the transect. The methane contents ofthe surface water as well as in the water column wereextremely inhomogeneous. Input by freshwater fromriver discharge and injection of methane from thesediment were both observed. The survey continued fromthe western side of the North Sea to the Elbe Riverestuary. The Elbe River appears to have low methaneconcentrations compared to other European rivers, itsaverage input into the North Sea is estimated to be70 nmol s-1 of methane. Near 58° N,1°40' E, an abandoned drill site releases about 25 % ofthe North Sea's emission of methane to the atmosphere.The advective methane transport induced by watercirculation was assessed for May 16, 1994, using a 3-DNorth Sea circulation model. For the period of thissurvey, the North Sea's source strength foratmospheric methane is estimated using in situwind velocities. In comparison to the advectivetransport by the water circulation, the gas flux tothe atmosphere appears to be the dominant sink ofNorth Sea methane. This flux is estimated to bebetween 1500 · 106 mol a-1 and 3100 ·106mol a-1, depending on the relationbetween wind speed and gas transfer velocity.