Drive mechanism for production of simulated human breath

Simulated breath drive mechanism was developed as subsystem to breathing metabolic simulator. Mechanism reproduces complete range of human breath rate, breath depth, and breath waveform, as well as independently controlled functional residual capacity. Mechanism was found capable of simulating various individual human breathing characteristics without any changes of parts

Shock enhancement and control of hypersonic mixing and combustion

The possibility that shock enhanced mixing can substantially increase the rate of mixing between coflowing streams of hydrogen and air has been studied in experimental and computational investigations. Early numerical computations indicated that the steady interaction between a weak shock in air with a coflowing hydrogen jet can be well approximated by the two-dimensional time-dependent interaction between a weak shock and an initially circular region filled with hydrogen imbedded in air. An experimental investigation of the latter process has been carned out in the Caltech 17 Inch Shock Tube in experiments in which the laser induced fluorescence of byacetyl dye is used as a tracer for the motion of the helium gas after shock waves have passed across the helium cylinder. The flow field has also been studied using an Euler code computation of the flow field. Both investigations show that the shock impinging process causes the light gas cylinder to split into two parts. One of these mixes rapidly with air and the other forms a stably stratified vortex pair which mixes more slowly; about 60% of the light gas mixes rapidly with the ambient fluid. The geometry of the flow field and the mixing process and scaling parameters are discussed here. The success of this program encouraged the exploration of a low drag injection system in which the basic concept of shock generated streamwise vorticity could be incorporated in an injector for a Scramjet combustor at Mach numbers between 5 and 8. The results of a substantial computational program and a description of the wind tunnel model and preliminary experimental results obtained in the High Reynolds Number Mach 6 Tunnel at NASA Langley Research Center are given here

Magnetic flux flow and superconductor stabilization Quarterly report, 1 Jan. - 31 Mar. 1968

Magnetic flux flow and stability of superconducting niobium titanium strip

Big Sur Visitor Characteristics and Wildland Fire Recreational Constraints

A study conducted with visitors to the Big Sur region of California during summer 2002 is presented. An onsite survey was administered to visitors to the U.S. Forest Service and California State Parks day-use and overnight facilities. Recreational constraints owing to wildland fire and fire management are detailed along with the effects of activity type, visitor demographics and other characteristics, and views of these constraints. Differences primarily exist in views of constraints related to regulations

Recreation and Fire Management in Urban National Forests: A Study of Manager Perspectives

The purpose of this study was to understand U.S. Department of Agriculture Forest Service public land managers’ perceptions of fire management and recreational use in urban national forests of the United States. An online survey was used to understand managers’ perceptions of (a) the degree to which the presence of recreational activities and experiences are a constraint to fire management, (b) the degree to which fire management and suppression activities influence the quality of a visit to a recreation site, and (c) the relationships between fire management and recreation constraints. In all, 62 district rangers within urban national forests were asked to complete an online survey, and 33 responded (53 percent). The following items were thought to moderately to severely impact the managers’ ability to manage fire: increased urban development, budget constraints, accumulation of burnable fuels, effect of smoke on visitors, increased visitation, and the lack of trained personnel. In addition, most managers believed that recreational use of day-use areas, trails, campgrounds, and access roads conflicted moderately or slightly with fire management decisions. Over 70 percent of respondents indicated that mountain bikes on unauthorized trails, vandalism, litter, encroachment from surrounding farmland, unauthorized grazing, and, unauthorized logging did not have an impact on fire management decisions. Generally respondents did not perceive management factors as limiting visitors’ pursuit of recreation activities. In addition, most managers identified the occurrence of various management activities (e.g., campground closures from smoke, trail closures owing to wildland fires, fire suppression, etc.) as slightly to not limiting at all

Place Attachment and Recreational Constraints Relating to Fire Management

This paper presents a study of visitors to the Big Sur region of California during summer 2001. An onsite survey was administered to visitors to USDA Forest Service day-use areas and at developed campgrounds. Place attachment, observations relating to fires and fire management, and perceived recreational constraints owing to wildland fire and fire management are examined. The results indicate that place dependence and place identity influence some perceived constraints and observations of fire conditions. A discussion of the findings is provided, emphasizing the importance of managers’ understanding of visitors’ perceptions relating to fire and fire management

Analysis of the impact of climate change on groundwater related hydrological fluxes: a multi-model approach including different downscaling methods

Climate change related modifications in the spatio-temporal distribution of precipitation and evapotranspiration will have an impact on groundwater resources. This study presents a modelling approach exploiting the advantages of integrated hydrological modelling and a broad climate model basis. We applied the integrated MIKE SHE model on a perialpine, small catchment in northern Switzerland near Zurich. To examine the impact of climate change we forced the hydrological model with data from eight GCM-RCM combinations showing systematic biases which are corrected by three different statistical downscaling methods, not only for precipitation but also for the variables that govern potential evapotranspiration. The downscaling methods are evaluated in a split sample test and the sensitivity of the downscaling procedure on the hydrological fluxes is analyzed. The RCMs resulted in very different projections of potential evapotranspiration and, especially, precipitation. All three downscaling methods reduced the differences between the predictions of the RCMs and all corrected predictions showed no future groundwater stress which can be related to an expected increase in precipitation during winter. It turned out that especially the timing of the precipitation and thus recharge is very important for the future development of the groundwater levels. However, the simulation experiments revealed the weaknesses of the downscaling methods which directly influence the predicted hydrological fluxes, and thus also the predicted groundwater levels. The downscaling process is identified as an important source of uncertainty in hydrological impact studies, which has to be accounted for. Therefore it is strongly recommended to test different downscaling methods by using verification data before applying them to climate model data