Electrokinetic phenomena in saturated compact clays

The membrane potential, the pressure difference, and the concentration difference induced by an applied concentration gradient through samples of compact clay were measured as functions of sodium chloride concentration and of porosity. The results of some previous numerical predictions are recalled to be functions of a characteristic length scale which can be derived from conductivity and permeability. Generally, the experimental data were in agreement with these numerical predictions. Therefore, nondiagonal coupling coefficients can be derived with acceptable precision from the diagonal coefficients

Thermodiffusional transport of electrolytes in compact clays

The macroscopic Soret coefficient ST was measured for three porous media, namely mica, glass powder, and natural compact clay. At a mean temperature of Click to view the MathML source and with NaCl, ST for mica and glass powder was found to be equal to (3.1±0.7)×10−3 K−1 and close to values for a free medium in agreement with theoretical predictions which are obtained under the assumption that the pressure gradient and the electric field are negligible on the pore scale. The main result is that for clay ST was found five times larger, presumably because of extra couplings with electrical phenomena. This latter measurement was confirmed by an independent technique based on the membrane potential

A simple model of light transmission through the atmosphere over the Baltic Sea utilising satellite data

A simple spectral model of solar energy input to the sea surface was extended to incorporate space-borne data. The extension involved finding a method of determining aerosol optical thickness (on the basis of AVHRR data) and the influence of cloudiness (on the basis of METEOSAT data) on the solar energy flux. The algorithm for satellite data assimilation involves the analysis of satellite images from the point of view of cloud identification and their classification with respect to light transmission. Solar energy input values measured at the Earth’s surface by traditional methods were used to calibrate and validate the model. Preliminary evaluation of the results indicates a substantial improvement in the accuracy of estimates of solar energy input to the sea surface in relation to models utilising only traditionally obtained data on the state of the atmosphere

SatBaltyk – A Baltic environmental satellite remote sensing system – an ongoing project in Poland. Part 2: Practical applicability and preliminary results

This paper is the second part of the description of the first stage of the SatBałtyk project’s implementation. Part 1 (Woźniak et al. 2011, in this issue) presents the assumptions and objectives of SatBałtyk and describes the most important stages in the history of our research, which is the foundation of this project. It also discusses the operation and general structure of the SatBałtyk system. Part 2 addresses various aspects of the practical applicability of the SatBałtyk Operational System to Baltic ecosystem monitoring. Examples are given of the Baltic’s characteristics estimated using the preliminary versions of the algorithms in this Operational System. At the current stage of research, these algorithms apply mainly to the characteristics of the solar energy influx and the distribution of this energy among the various processes taking place in the atmosphere-sea system, and also to the radiation balance of the sea surface, the irradiance conditions for photosynthesis and the condition of plant communities in the water, sea surface temperature distributions and some other marine phenomena correlated with this temperature. Monitoring results obtained with these preliminary algorithms are exemplified in the form of distribution maps of selected abiotic parameters of the Baltic, as well as structural and functional characteristics of this ecosystem governed by these parameters in the Baltic’s many basins. The maps cover practically the whole area of the Baltic Sea. Also given are results of preliminary inspections of the accuracy of the magnitudes shown on the maps. In actual fact, the errors of these estimates are relatively small. The further practical application of this set of algorithms (to be gradually made more specific) is therefore entirely justified as the basis of the SatBałtyk system for the effective operational monitoring of the state and functioning of Baltic ecosystems. This article also outlines the plans for extending SatBałtyk to include the recording of the effects and hazards caused by current and expected storm events in the Polish coastal zone

Research Challenges Involving Coupled Flows in Geotechnical Engineering

Coupled fluid, chemical, heat, and electrical flows are common phenomena that arc relevant to a wide variety of applications in Geotechnical Engineering, including the use of engineered clay barriers for waste containment, electro-osmosis for soil consolidation, highly compacted bentonite buffers for high-level radioactive nuclear waste disposal, and electrokinetics for soil contaminant removal. among others. For all of these applications, a fundamental understanding of coupled flow phenomena is required, including the basis of the various phenomena. the potential effect of the phenomena on fundamental soil behavior, and the applicability of the phenomena in both natural and built environments. This chapter highlights some of the advances over the past approximate three decades, including the effects of osmotic phenomena (chemico-osmosis, electro-osmosis, and thermo-osmosis) on the mechanical behavior of clays, the formulations and measurement of coupled flow phenomena, the distinction between phenomenological and microscopic (physical-based) formalisms, and considerations with respect to both saturated and unsaturated soil conditions. Based on the description of these advances, research challenges pertaining lo the study of coupled flow phenomena for Geotechnical Engineering applications are identified