Making space for unruly water: Sustainable drainage systems and the disciplining of surface runoff

This paper explores the disciplining of non-human actors through the example of sustainable drainage systems (SuDS) managing surface water runoff. The lens of performativity is used to examine the move from pre-modern repressive forms of discipline, to mechanisms which attempt a more productive disciplinary engagement by finding space to reform water’s more unruly behaviours. After examining the problems with traditional disciplinary approaches to water of rapid transit and exile, the paper explores the implications of a move towards SuDS technology. This change is examined using a case study of Glasgow, Scotland, where there is an attempt to utilise less repressive disciplinary mechanisms and to find spaces in the city for surface water outside the hard drainage infrastructure. New approaches to the disciplining of urban water are conceptualised as being a performance of tension between water and those who would modify its behaviour.     

The effect of pH and ionic strength on proton adsorption by the thermophilic bacterium Anoxybacillus flavithermus

Numerous studies have utilized surface complexation theory to model proton adsorption behaviour onto mesophilic bacteria. However, few experiments, to date, have investigated the effects of pH and ionic strength on proton interactions with thermophilic bacteria. In this study, we characterize proton adsorption by the thermophile Anoxybacillus flavithermus by performing acid-base titrations and electrophoretic mobility measurements in NaNO₃ (0.001-0.1 M). Equilibrium thermodynamics (Donnan model) were applied to describe the specific chemical reactions that occur at the water-bacteria interface. Acid-base titrations were used to determine deprotonation constants and site concentrations for the important cell wall functional groups, while electrophoretic mobility data were used to further constrain the model. We observe that with increasing pH and ionic strength, the buffering capacity increases and the electrophoretic mobility decreases. We develop a single surface complexation model to describe proton interactions with the cells, both as a function of pH and ionic strength. Based on the model, the acid-base properties of the cell wall of A. flavithermus can best be characterized by invoking three distinct types of cell wall functional groups, with pK_a values of 4.94, 6.85, and 7.85, and site concentrations of 5.33, 1.79, and 1.42 × 10⁻⁴ moles per gram of dry bacteria, respectively. A. flavithermus imparts less buffering capacity than pure mesophilic bacteria studied to date because the thermophile possesses a lower total site density (8.54 × 10⁻⁴ moles per dry gram bacteria).     

Effect of different growth parameters on endoglucanase enzyme activity by bacteria isolated from coir retting effluents of estuarine environment

The cellulolytic enzyme-endoglucanase activity against coir fibre, a major biowaste by bacteria such as Cellulomonas, Bacillus and Micrococcus spp. isolated from coir retting effluents of estuarine environment was studied. The enzyme assay was carried out by using various concentrations (0.5 ? 2%) of substrate of coir powder as a carbohydrate in different pH (5–9) and temperature (20–50 °C). The enzyme activity was minimum in 0.5% substrate concentration at lower pH 5 (0.0087, 0.0143 and 0.0071 U/mL) and at 20 °C temperature (0.0151, 0.0154 and 0.0122 U/mL) by the bacterial strains such as Cellulomonas, Bacillus and Micrococcus spp respectively. Then this level was increased and reached maximum at the neutral pH (0.0172, 0.0165 and 0.0121 U/mL) and at 40 °C (0.0336, 0.0196 and 0.0152 U/mL) by the selected bacterial species. Further increase of pH and temperature, the enzyme activity reduced considerably to 0.0083, 0.0143 and 0.0037 U/mL at pH 9 and 0.0154, 0.0197 and 0.0121 U/mL at 50 °C by the tested bacterial strains. The same trend was also obtained in oth er substrate concentrations such as 1.0, 1.5 and 2.0 %. With in the four substrate concentrations, the endoglucanase enzyme activity was more in 1.5% concentration at the tested pH and temperatures. From the over all result, it was observed that, among the three bacterial strains, the enzyme activity was more in Cellulomonas sp, followed by Bacillus and Micrococcus spp. in varying pH and temperature.     

Terrain analysis of the Racetrack Basin and the sliding rocks of Death Valley

The Racetrack Playa's unusual surface features known as sliding rocks have been the subject of an ongoing debate and several mapping projects for half a century, although the causative mechanism remains unresolved. Clasts ranging in volume from large pebbles to medium boulders have, unwitnessed, maneuvered around the nearly flat dry lake over considerable distances. The controversy has persisted partly because eyewitness accounts of the phenomenon continue to be lacking, and the earlier mapping missions were limited in method and geographic range. In July 1996, we generated the first complete map of all observed sliding rock trails by submeter differential Global Positioning System (DGPS) mapping technology. The resulting map shows 162 sliding rocks and associated trails to an accuracy of approximately 30 cm. Although anemometer data are not available in the Racetrack wilderness, wind is clearly a catalyst for sliding rock activity; an inferred wind rose was constructed from DGPS trail segment data. When the entire trail network is examined in plan, some patterns emerge, although other (perhaps expected relations) remain elusive: terrain analysis of the surrounding topography demonstrates that the length and morphology of trails are more closely related to where rocks rested at the onset of motion than to any physical attribute of the rocks themselves. Follow-up surveys in May 1998, May 1999, August 1999, and November 1999 revealed little modification of the July, 1996 sliding rock configuration. Only four rocks were repositioned during the El Niño winter of 1997–1998, suggesting that activity may not be restricted to winter storms.