TRACES OF THE TERRITORY IN SPANISH PHOTOGRAPHY SINCE THE 1990s

This paper proposes a reading of the cultural and social aspects associated with sundry notions of territory through Spanish photography at the end of the twentieth century and the beginning of the twenty-first. An analysis of a series of case studies reveals a new awareness of the common space through the concept of trace, being understood beyond the material imprint, as it falls under the influence of the cultural aspects that clarify the account of the conflict and consciousness of the suburbs and peripheries. Contemporary ruins arising from unbridled urban growth, or the invisible wounds associated with certain places, converge in a series of images that have their own tradition in the conceptual experiments of the 70s and the aesthetics of the “non-site” displayed in the 90s. As background, the economic and political avatars of recent years in Spain – also linked to a global crisis – are manifested in a series of photographic musings whose images portray the scenarios of a premature ruin linked to property speculation and the traces of a collective memory.     

Mine inonoations

The paper describes the types of inundations affecting underground mining operations together with their safety, operational, and stability implications. A critical analysis has highlighted three major causes of inundations. These have been classified as event controlled, accidental or spontaneous. The event controlled inundations are associated with the development of fracture zones around a longwall working and followed by main and periodic roof falls in caved mine workings, particularly in coal mines. An approximate theory to predict the event of main and periodic roof falls in the goaf behind the long wall face is given. These types of inundations have been illustrated with several case histories.     

Design considerations for mine workings under accumulations of water

The study outlines the effects of surface and underground subsidence patterns on the spatial distribution of in-situ permeability and its effects on groundwater inflow. The behaviour of strata surrounding a longwall face where limited knowledge exists has been outlined. The effects of mining subsidence on the surface flow pattern have been described with the remedial solutions. The mechanism of formation of sinkholes in certain chemical rockmass has been described. Factors affecting mine water inflow have been described in detail with the aid of a simplified conceptual model and case studies. Practical examples of undersea workings and those under a large accumulation of water are given, both in the United Kingdom and worldwide.     

The performance of activated sludge plants compared with the results of various bacterial toxicity tests—A study with 3,5-dichlorphenol

It was investigated whether and to what extent the results obtained by various methods of determining bacterial toxicity in waste water could be applied to conditions prevailing in activated sludge plants or in receiving water.3.5-Dichlorphenol (DCP) was studied as an example of a persistent chemical which constitutes a pollution risk to water. The bacterial toxicity limits determined by five different methods—respiration after a 20-h consumption period, consumption rate after 2-h incubation, dehydrogenase activity determined with TTC. gas formation in a fermentation tube and inhibition of the cell division of Pseudomonas—all agreed with the toxicity limit of 5 mg DCP I⁻¹ found in degradation tests in laboratory activated sludge equipment. No safety margin need be taken into account when the test results are applied to biological purification plants.In the activated sludge plants the degradation of the industrial waste water was markedly impaired only when the DCP concentration was increased to 25 mg I⁻¹. This varied in degree according to the sludge load at the beginning of the trial.Shock loads of DCP did not cause the expected fall-off in degradation but only a moderate fluctuation in its rate. The decline in degradation following continuous and also discontinuous addition of DCP was largely or completely overcome within a few weeks by the bacteria becoming adapted to DCP.In samples of river water the toxicity limit as determined by the tests was in the region of 2 mg I⁻¹.     

Effect of agitation, turbidity, aluminium foil reflectors and container volume on the inactivation efficiency of batch-process solar disinfectors

We report the results of experiments designed to improve the efficacy of the solar disinfection of drinking water, inactivation process. The effects of periodic agitation, covering the rear surface of the container with aluminium foil, container volume and turbidity on the solar inactivation kinetics of Escherichia coli (starting population = 10(6) CFU ml(-1)) were investigated. It was shown that agitation promoted the release of dissolved oxygen from water with subsequent decrease in the inactivation rates of E. coli. In contrast, covering the rear surface of the solar disinfection container with aluminium foil improved the inactivation efficiency of the system. The mean decay constant for bacterial populations in foil-backed bottles was found to be a factor of 1.85 (std. dev. = 0.43) higher than that of non-foil-backed bottles. Inactivation rates decrease as turbidity increases. However, total inactivation was achievable in 300 NTU samples within 8 h exposure to strong sunshine. Inactivation kinetics was not dependent on the volume of the water container for volumes in the range 500-1500 ml.