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Water Delivery (water + delivery)
Selected AbstractsHydrological connectivity of soil pipes determined by ground-penetrating radar tracer detectionEARTH SURFACE PROCESSES AND LANDFORMS, Issue 4 2004Joseph Holden Abstract Soil pipes are common and important features of many catchments, particularly in semi-arid and humid areas, and can contribute a large proportion of runoff to river systems. They may also signi,cantly in,uence catchment sediment and solute yield. However, there are often problems in ,nding and de,ning soil pipe networks which are located deep below the surface. Ground-penetrating radar (GPR) has been used for non-destructive identi,cation and mapping of soil pipes in blanket peat catchments. While GPR can identify subsurface cavities, it cannot alone determine hydrological connectivity between one cavity and another. This paper presents results from an experiment to test the ability of GPR to establish hydrological connectivity between pipes through use of a tracer solution. Sodium chloride was injected into pipe cavities previously detected by the radar. The GPR was placed downslope of the injection points and positioned on the ground directly above detected soil pipes. The resultant radargrams showed signi,cant changes in re,ectance from some cavities and no change from others. Pipe waters were sampled in order to check the radar results. Changes in electrical conductivity of the pipe water could be detected by the GPR, without data post-processing, when background levels were increased by more than approximately twofold. It was thus possible to rapidly determine hydrological connectivity of soil pipes within dense pipe networks across hillslopes without ground disturbance. It was also possible to remotely measure travel times through pipe systems; the passing of the salt wave below the GPR produced an easily detectable signal on the radargram which required no post-processing. The technique should allow remote sensing of water sources and sinks for soil pipes below the surface. The improved understanding of ,owpath connectivity will be important for understanding water delivery, solutional and particulate denudation, and hydrological and geomorphological model development. Copyright © 2004 John Wiley & Sons, Ltd. [source] Lower airway humidification in spontaneously breathing tracheostomized patients: Comparative study of trachea spray versus heated humidifierHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 5 2008Tilman Keck MD Abstract Background. Our aim was to compare inhalation with molecular water (vaporizing humidifier) and particulate water (trachea spray) in spontaneously breathing tracheostomized patients. Methods. We performed a randomized, 2-way crossover study and a prospective, comparative, nonblinded study. Tracheal humidity and temperature were measured before and after use of a humidifier and spray for 1 week. Results. After both inhalation and spray, the tracheal temperature and total water content increased significantly (study 1). The temperature gradient between ambient and tracheal air was significantly higher after spray, but not after inhalation (study 2). The water gradient increased nonsignificantly after spray and inhalation. The water gradient after inhalation or spray did not differ significantly. Conclusions. Molecular water is not superior to particulate water because of temperature and humidity increase after both forms of water delivery. Because of its easy use, portability, and moisturizing effect, a trachea spray may offer additional options in postoperative tracheostomy care. © 2007 Wiley Periodicals, Inc. Head Neck, 2008 [source] Hillslope-swamp interactions and flow pathways in a hypermaritime rainforest, British ColumbiaHYDROLOGICAL PROCESSES, Issue 15 2003D. F. Fitzgerald Abstract The process of water delivery to a headwater stream in a hypermaritime rainforest was examined using a variety of physical techniques and tracing with dissolved organic carbon (DOC) and the stable isotopes of water. Headwater swamps, often the major discharge zones for water draining off steep forest slopes, strongly affect the physical and chemical character of streamflow in the region. The headwater swamp selected for detailed investigation was sustained by relatively constant groundwater input from the steep colluvial slopes that maintained the water table above the ground surface. During significant storm events the water table rose quickly and the swamp expanded to engulf marginal pools that developed rapidly on the adjacent ground surfaces. The corresponding release of surface water directly to the stream typically comprised up to 95% of total stream discharge. The proportion of groundwater seepage to the stream by matrix flow (<1%) and via macropore-fed springs (up to 73%) increased during the recession period, but could not be sustained over the longer term. In more protracted drying periods, deep groundwater contributions to the stream were routed first to the headwater swamp. Dissolved organic carbon (DOC) in the stream, measured daily or more frequently during storm events, was found to be directly proportional to discharge, owing to the domination of DOC-rich headwater-swamp water sources. Although ,18O and ,2H composition of rainwater, groundwater and stream flow were found to be similar, deuterium excess (d ,2H , 8,18O) of water components was often found to be distinct, and suggested short water residence times of roughly 12 days for one event. Overall, observations of a typical headwater swamp reveal that the groundwater regime is dominated by rapid infiltration and short, emergent flow paths. With a relatively short turnover time, potential disturbances to the system by harvesting of upslope areas can be expected to occur rapidly. Forest managers can mitigate some of the harmful effects of logging operations by respecting the integrity of headwater wetland systems. The nature and magnitude of such perturbations will require further study. Copyright © 2003 John Wiley & Sons, Ltd. [source] Does the minimal phototoxic dose after 8-methoxypsoralen baths correlate with the individual's skin phototype?PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2001Ralf Schiener Background/Aims: Up to now no data have been available concerning whether there is a significant correlation between skin phototypes and the minimum phototoxic dose (MPD) after bath water delivery of 8-MOP. Methods: The skin phototype of each of 46 patients was determined based on the individual past history of solar-induced burning and tanning. In addition, the MPD of each patient was assesed after photosensitization with a warm water bath (37 °C, 98.6 °F) containing 1.0 mg/l 8-methoxypsoralen (8-MOP). Statistical analysis was performed using a Mann-Whitney U-test and Spearman rank order correlation. Results: The median MPD in patients with skin phototype II was 2.0 J/cm2 (range ,0.5 to ,3.5) versus 1.5 J/cm2 (range 1.0 to ,3.5) in patients with skin phototype III. There was a considerable overlap between both groups. No significant difference was detected comparing both groups (P=0.7326) and Spearman rank order correlation revealed no correlation between skin phototype and MPD. Conclusion: Erythemal sensitivity in PUVA bath therapy, measured as MPD, is not correlated with sun-reactive skin phototype in skin types II and III. Thus skin phototype is not a suitable indicator for the initial UVA dose in PUVA bath photochemotherapy. [source] | ||||||||||