The relevance and magnitude of an electroosmotic perfusion mechanism in electrochromatography is analyzed. To systemize our studies we first considered the transport of an electroneutral and nonadsorbing tracer. Based on the refractive index matching in a microfluidic setup containing fixed spherical porous particles, we conducted a quantitative analysis in real time of the spatio-temporal distribution of fluorescent tracer molecules during their uptake by (and a release from) single particles using confocal laser scanning microscopy. Even under conditions of a significant electrical double layer overlap the intraparticle electroosmotic flow produces due to its unidirectional nature and in striking contrast to the symmetric (spherical) distributions typical for purely diffusive transport strongly asymmetric concentration profiles inside spherical particles as the locally charged pore liquid begins to respond to the externally applied electrical field. The profiles retain an axisymmetric nature, i.e., rotational symmetry with respect to the field direction. Results of our measurements could be successfully interpreted and further analyzed by a compact mathematical model. Intraparticle Peclet numbers of up to 150 have been realized and found to significantly enhance the mass transport on particle scale towards the convection-dominated regime when compared to a conventional (diffusion-limited) kinetics.

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A mathematical modelling approach for open-tubular capillary electrochromatography is presented. The spatially one-dimensional model takes into account (i) a coupling of (non)linear adsorption of positively or negatively charged analyte molecules (at a negatively charged capillary inner surface) with the equilibrium electrokinetics at this solid-liquid interface, (ii) mobile phase transport by electroosmosis and pressure-driven flow, as well as (iii) transport of species by electrophoresis and molecular diffusion. Under these conditions the local zeta-potential and electroosmotic mobility become a function of the concentration of the charged analyte. The resulting inhomogeneity of electroosmotic flow through the capillary produces a compensating pore pressure as requirement for incompressible mobile phase flow (i.e., for constant volumetric flow along the capillary). The results of the simulations are discussed in view of the surface-to-volume ratio of the capillary lumen, the analyte concentration (in combination with a Langmuir isotherm for the adsorption process), and buffer effects.

The chromatographic performance with respect to the flow behavior and dispersion in fixed beds of nonporous and macroporous particles (having mean intraparticle pore diameters of 41, 105, and 232 nm) has been studied in capillary HPLC and electrochromatography. The existence of substantial electroosmotic intraparticle pore flow (perfusive electroosmosis) in columns packed with the macroporous particles was found to reduce stagnant mobile mass transfer resistance and decrease the global flow inhomogeneity over the column cross-section, leading to a significant improvement in column efficiency compared to capillary HPLC. The effect of electroosmotic perfusion on axial dispersion was shown to be sensitive to the mobile phase ionic strength and mean intraparticle pore diameter, thus, on an electrical double layer interaction within the particles. Complementary and consistent results were observed for the average electroosmotic flow through packed capillaries. It was found to depend on particle porosity and distinct contributions to the electrical double layer behavior within and between particles. Based on these data an optimum chromatographic performance in view of speed and efficiency can be achieved by straightforward adjustment of the electrolyte concentration and characteristic intraparticle pore size.

VirES is a Virtual workspace for Earth-observation Scientists, a service provided by the European Space Agency (ESA). VirES has firstly been established for ESA's magnetic field mission Swarm as "VirES for Swarm" [1] and has been extended to ESA's atmospheric dynamics mission Aeolus, which was launched in August 2018. The service is developed by the Austrian IT company EOX in strong collaboration with missions' scientists. VirES is a web-based service (https://aeolus.services) that enables scientists to discover, visualize, select and download data of Earth-observation (EO) missions through an easy to operate graphical user interface. "VirES for Aeolus" [2] will provide access to Aeolus L1B, L2A, L2B, L2C products and auxiliary data. The first version 1.0 passed acceptance tests in April 2018 and developments towards Version 1.2 are in progress. The service is planned to be accessible for public use as soon as the mission's phase E1 is completed and first data products are released by ESA.

Problems of theoretical description and practical use of nonlinear phenomena arising in the conduction of electric current in electrolytes with a non-homogeneous spatial distribution of species concentrations and with equilibrium reactions are studied in this contribution. Mathematical model based on the mass balances of components, Nernst-Planck equation and Poisson equation is presented. Results of numerical simulations are discussed for systems: (i) acid-base electrolyte diode in the hydrogel and (ii) bipolar ion-exchange membranes. 236 A New Static Mixer for Turbulent Flow M a r k u s F l e i s c h l i P e t e r M a t h y s T h o m a s G r u È t t e rA new static mixer for turbulent flow has been developed. The integrated feeding device is designed for mixing ratios of additive to main stream of 0.05 ± 30 %. The mixer has a very short installation length (`0.5 pipe diameter). It can be easily mounted between two flanges. Mixing length and pressure drop are reduced compared to the traditional SMI mixer. 237 Scale-Up of Processes Using Material Systems with Variable Physical Properties M a r k o Z l o k a r n i k A ± 8010 Graz, Grillparzerstrasse 58Two processes are similar to one another if they take place in a similar geometrical space and if all the dimensionless numbers which describe the process have the same numerical value: A complete similarity requires a geometrical, material and process-related similarity. When measurements are to be performed in a ªcold mod-elº, but the industrial plant operates at high temperatures (petrochemicals; T 800 ± 1000 C), different temperature dependence of physical properties can cause problems. When measurements are to be performed with model fluids to gain information about scaling-up of an apparatus for the treatment of cell cultures in biotechnology (mammal and plant cells, yeasts), their rheological behaviour (pseudoplactic and viscoelastic) can present problem. Which model system may we choose? The answer will be unambiguous: We may choose any model material system whose dimensionless material function in question is similar to that of the original material system. It will be shown how to proceed to arrive at it.Homogeneous and heterogeneously catalyzed esterification kinetics of lactic acid with methanol are studied in this work. The effect of temperature, catalysts loading and initial reactant ratio on reaction kinetics is evaluated.Experimental reaction rates were correlated by some models based on homogeneous and heterogeneous (dual and single site mechanism) approaches. Non-ideality of the liquid phase was taken into account by using activities instead of mol fractions. Prediction of the activity coefficients were made by UNIFAC. Parameters of the different models were obtained by the simplex search method. Figure.Variation of conversion with time for the non-catalyzed esterification of lactic acid with methanol at different temperatures. The reaction was carried out with an initial methanol/lactic acid ratio R M/LH =3. The continuous line represents the model ...

<p>The VirES service can be described as an ecosystem: the VirES server provides robust API-based access to both data and models derived from Swarm measurements; the VirES web interface provides visual point-and-click access [1]; the viresclient Python package provides the basis for a programmatic workflow and connection to the scientific Python landscape [2]; the Virtual Research Environment (VRE) provides a ready-to-code Jupyter environment to empower researchers to quickly start writing and running code using the latest Python packages [3].<br /><br />In tandem with the evolution of the Swarm product portfolio, VirES evolves to provide access to and visualisation of new data products as they are published. Beyond this, Swarm activities are shifting away from static data products and toward on-demand processing and tools. We support development and dissemination of such tools in a scientist-led way through the VRE. These take the form of both computational notebooks and of Python packages.<br /><br />With a growing number of data sources, both Earth-bound and orbital, it is critical to enable easier multi-dataset scientific workflows. At the same time, there is a multiplicity of research software projects, complex to navigate and make use of. We are tackling these issues through adoption of the Heliophysics API specification (HAPI [4, 5]), and coordination with the Python in Heliophysics Community.<br /><br />[1] https://vires.services<br />[2] https://viresclient.readthedocs.io<br />[3] https://notebooks.vires.services<br />[4] https://hapi-server.org<br />[5] https://vires.services/hapi</p>

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