A design procedure for the weight optimization of straight finned radiators

Design technique evaluates optimum weight of space radiator consisting of finned, right circular cylinder

PROGRESS REPORT ON FRICTION LOSS OF SLURRIES IN STRAIGHT TUBES

This progress report summarizes the results obtained to date on the experimental evaluation of the loss of head entailed in pumping slurries through a straight horizontal tube. The slurries used in the investigation consisted of spherical particles of glass, steel and lead in water. The particle size and concentrations were nominally constant for a given slurry, but the various slurries tested covered the size range from 0.00122 to 0.0722 inches in diameter. Concentrations from zero to approximately 50 per cent by weight were used.</p

A Systematic Review of Quantitative Resilience Measures for Water Infrastructure Systems

Over the past few decades, the concept of resilience has emerged as an important consideration in the planning and management of water infrastructure systems. Accordingly, various resilience measures have been developed for the quantitative evaluation and decision-making of systems. There are, however, numerous considerations and no clear choice of which measure, if any, provides the most appropriate representation of resilience for a given application. This study provides a critical review of quantitative approaches to measure the resilience of water infrastructure systems, with a focus on water resources and distribution systems. A compilation of 11 criteria evaluating 21 selected resilience measures addressing major features of resilience is developed using the Axiomatic Design process. Existing gaps of resilience measures are identified based on the review criteria. The results show that resilience measures have generally paid less attention to cascading damage to interrelated systems, rapid identification of failure, physical damage of system components, and time variation of resilience. Concluding the paper, improvements to resilience measures are recommended. The findings contribute to our understanding of gaps and provide information to help further improve resilience measures of water infrastructure systems

Impacts of elevation data spatial resolution on two-dimensional dam break flood simulation and consequence assessment

A grid resolution sensitivity analysis using a two-dimensional flood inundation model has been presented in this paper. Simulations for 6 dam breaches located randomly in the United States were run at 10,30,60,90, and 120 meter resolutions. The dams represent a range of topographic conditions, ranging from 0% slope to 1.5% downstream of the dam. Using 10 meter digital elevation model (DEM) simulation results as the baseline, the coarser simulation results were compared in terms of flood inundation area, peak depths, flood wave travel time, daytime and nighttime population in flooded area, and economic impacts. The results of the study were consistent with previous grid resolution studies in terms of inundated area, depths, and velocity impacts. The results showed that as grid resolution is decreased, the relative fit of inundated area between the baseline and coarser resolution decreased slightly. This is further characterized by increasing over prediction as well as increasing under prediction with decreasing resolution. Comparison of average peak depths showed that depths generally decreased as resolution decreased, as well as the velocity. It is, however, noted that the trends in depth and velocity showed less consistency than the inundation area metrics. This may indicate that for studies in which velocity and depths must be resolved more accurately (urban environments when flow around buildings is important in the calculation of drag effects), higher resolution DEM data should be used. Perhaps the most significant finding from this study is the perceived insensitivity of socio-economic impacts to grid resolution. The difference in population at risk (PAR) and economic cost generally remained within 10% of the estimated impacts using the high resolution DEM. This insensitivity has been attributed to over estimated flood area and associated socio-economic impacts compensating for under estimated flooded area and associated socio-economic impacts. The United States has many dams that are classified as high-hazard potential that need an emergency action plan (EAP). It has been found that the development of EAPs for all high-hazard dams is handicapped due to funding limitations. The majority of the cost associated with developing an EAP is determining the flooded area. The results of this study have shown that coarse resolution dam breach studies can be used to provide an acceptable estimate of the inundated area and economic impacts, with very little computational cost. Therefore, the solution to limited funding may be to perform coarse resolution dam breach studies on high-hazard potential dams and use the results to help prioritize the order in which detailed EAPs should be developed

Response of spent LWR fuel to extreme environments

The research reported in this paper addresses the radiological source term which could arise when irradiated fuel in transport from a commercial light water reactor is exposed to the extreme environments postulated for some transportation accidents, specifically those involving a fire. The release of spent fuel radionuclides to the environment requires a breach of both the cask and the fuel rod cladding. Past research has given significant emphasis to evaluating the response of the shipping cask to mechanical and/or thermal loads from hypothetical accidents. Less consideration has been given to evaluating the response of the fuel rods to these environments. In this paper, the response of the fuel rods to an extreme thermal event was experimentally evaluated and the quantity of solid fuel material that could be released from the fuel rods to the cask cavity was estimated. Briefly, the objectives of this study were as follows: (1) Identify those conditions within a transportation cask which might produce fuel-rod cladding failure, emphasizing conditions associated with fires, and (2) Determine by experiment and analysis the nature of the source term so produced. The release of radionuclides from coolant or deposits on the outer surfaces of the fuel assembly was not addressed in this study. 6 figs., 2 figs

Integration of SWMM into a Dam Break, Hurricane, and Extreme Flood Modeling and Damage Assessment Framework

SWMM5 has been seamlessly integrated with a Geographic Information System (GIS) for simulation of inundation and analysis of consequences resulting from extreme flood events. The GIS-based environment processes digital elevation models, land use/cover data, stream networks and soils to create stream network, sub-basins, and cross-section shapefiles for river basins selected for analysis. The following readily-available public-domain datasets are utilized: 30-m topographical data from the United States Geological Survey (USGS), 30-m NLCD, Natural Resources Conservation Service (NRCS) (STATSGO), and National Hydrography Dataset (NHD). Rainfall predictions are made by a numerical weather model and ingested in gridded format into the simulation environment. Runoff hydrographs are estimated using Green-Ampt infiltration excess runoff prediction and a onedimensional diffusive wave overland flow routing approach. The hydrographs and the channel morphology are used to generate a SWMM5 compatibl

What do experienced water managers think of water resources of our nation and its management infrastructure?

This article represents the second report by an ASCE Task Committee Infrastructure Impacts of Landscape-driven Weather Change under the ASCE Watershed Management Technical Committee and the ASCE Hydroclimate Technical Committee. Herein, the \u27infrastructure impacts are referred to as infrastructure-sensitive changes in weather and climate patterns (extremes and non-extremes) that are modulated, among other factors, by changes in landscape, land use and land cover change. In this first report, the article argued for explicitly considering the well-established feedbacks triggered by infrastructure systems to the land-atmosphere system via landscape change. In this report by the ASCE Task Committee (TC), we present the results of this ASCE TC\u27s survey of a cross section of experienced water managers using a set of carefully crafted questions. These questions covered water resources management, infrastructure resiliency and recommendations for inclusion in education and curriculum. We describe here the specifics of the survey and the results obtained in the form of statistical averages on the \u27perception\u27 of these managers. Finally, we discuss what these \u27perception\u27 averages may indicate to the ASCE TC and community as a whole for stewardship of the civil engineering profession. The survey and the responses gathered are not exhaustive nor do they represent the ASCE-endorsed viewpoint. However, the survey provides a critical first step to developing the framework of a research and education plan for ASCE. Given the Water Resources Reform and Development Act passed in 2014, we must now take into account the perceived concerns of the water management community. © 2015 Hossain et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited