The feasibility of boron removal from water by capacitive deionization

We report on the possibility of removing boron (in the form of boric acid) from water by electrochemical means. We explore capacitive de-ionization (CDI) processes in which local changes in pH near the surface of high-surface-area activated carbon fiber (ACF) electrodes during charging are utilized, in order to dissociate boric acid into borate ions which can be electro-adsorbed onto the positive electrode in the CDI cells. For this purpose, a special flow-through CDI cell was constructed in which the feed solution flows through the electrodes. Local pH changes near the carbon electrode surface were investigated using a MgCl₂ solution probe in three- (with reference) and two-electrode cells, and described qualitatively. We show that, to a certain extent, boron can indeed be removed from water by CDI.     

Water desalting by means of electrochemical parametric pumping. II. Separation properties of a multistage column

Multistage electrochemical parametric pumping has been successfully carried out for water desalination. Separation was effected by electroadsorption-desorption cycles of the ions into and from the electrical double layer of high surface carbon electrodes. At steady state and total reflux, the concentration ratio between the upper and lower heads of the electrochemical column was as high as 150. Two models for the build up of the concentration profile within the column are presented. The first is based on a solution of the two-phase mass transport equation using the proper boundary and initial conditions. The second treatment is based on the mixed cells assumptions. In both treatments, interphase equilibrium is assumed using the isopotentiograms as the specific equilibrium curves. Use is also made of a fast computer for the simulation of the electrochemical paramatric pumping cycles. The two models are in good agreement with the experimental results particularly in the cases where the initial concentration is high and interphase equilibrium is maintained.     

Threshold flux in fouling of OF membranes by colloidal iron

Fouling of 50 kDa MWCO OF membranes by iron colloid solutions was studied under constant pressure conditions and constant flux conditions at pH 5 and 7 and at various iron concentrations. By using measurements of both deposit density and changes in the transmembrane zeta potential, threshold fluxes were found that were significantly lower than the critical flux based on the increase in membrane resistance. Results are consistent with the initial phase of fouling involving pore blockage followed by cake filtration-like behavior. The dependence of fouling rate on iron colloid concentration can best be understood by realizing that only a small fraction of the iron colloid is of a size that contributes to fouling.     

Increasing motorcycles attention and search conspicuity by using Alternating-Blinking Lights System (ABLS)

Poor conspicuity of Powered Two-Wheelers (PTW) is one of the main factors contributing to their involvement in accidents. The current study examined the influence of different rider's outfits on PTWs’ detectability, and evaluated the potential of a unique Alternating-Blinking Lights System (ABLS) to increase the rider's conspicuity. This study included two experiments that examined the visual search involved in the process of scanning video clips of dynamic traffic scenes. The first experiment examined PTWs’ attention conspicuity, while the second evaluated PTWs’ search conspicuity. In the attention conspicuity experiment participants were not alerted to the possible presence of a PTW and were asked to report the types of vehicles that were present in each video clip. In the search conspicuity experiment the participants were asked to actively search for a PTW and report its presence or absence in each video clip. Every participant was presented with a series of 96 video clips, 48 with a PTW and 48 without (controls). The independent variables were: (i) level of ambient illumination, (ii) road type, (iii) PTW's initial distance from the viewer, and (iv) rider's outfit. The results of the attention conspicuity experiment indicated that the environmental context has a strong effect on the probability of detecting the PTW. The ABLS increased the PTWs’ attention conspicuity by moderating the effects of environmental context, and was most effective at dusk and in urban environments. The results of the search experiment indicated that detection rates decreased and reaction time (RT) increased as the level of luminance decreased. RT was shortest with the ABLS across all driving environments. The ABLS increased PTWs detection rates in both experiments and mitigated the difference in detection rates between the attention and search conspicuity experiments. The results indicated that the ABLS was the most potent conspicuity treatment of the ones evaluated in this study. In conclusion, PTW conspicuity should be enhanced by incorporating aspects of both attention and search conspicuity. The riders need to take into consideration the perceptual characteristics of their riding environment, and be equipped with a conspicuity aid that is less susceptible to the changing environment and provides the rider with a unique visual signature. In parallel, the expectancy of car drivers to the presence of PTWs should be increased.     

MARCO: MAp retrieval by COntent

A system named MARCO (denoting map retrieval by content) that is used for the acquisition, storage, indexing, and retrieval of map images is presented. The input to MARCO are raster images of separate map layers and raster images of map composites. A legend-driven map interpretation system converts map layer images from their physical representation to their logical representation. This logical representation is then used to automatically index both the composite and the layer images. Methods for incorporating logical and physical layer images as well as composite images into the framework of a relational database management system are described. Indices are constructed on both the contextual and the spatial data thereby enabling efficient retrieval of layer and composite images based on contextual as well as spatial specifications. Example queries and query processing strategies using these indices are described. The user interface is demonstrated via the execution of an example query. Results of an experimental study on a large amount of data are presented. The system is evaluated in terms of accuracy and in terms of query execution time