4 results on '"Whittier N"'
Search Results
2. An LNG release, transport, and fate model system for marine spills.
- Author
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Spaulding ML, Swanson JC, Jayko K, and Whittier N
- Subjects
- Geographic Information Systems, Reproducibility of Results, Seawater, Ships, Accidents, Fossil Fuels, Models, Theoretical
- Abstract
LNGMAP, a fully integrated, geographic information based modular system, has been developed to predict the fate and transport of marine spills of LNG. The model is organized as a discrete set of linked algorithms that represent the processes (time dependent release rate, spreading, transport on the water surface, evaporation from the water surface, transport and dispersion in the atmosphere, and, if ignited, burning and associated radiated heat fields) affecting LNG once it is released into the environment. A particle-based approach is employed in which discrete masses of LNG released from the source are modeled as individual masses of LNG or spillets. The model is designed to predict the gas mass balance as a function of time and to display the spatial and temporal evolution of the gas (and radiated energy field). LNGMAP has been validated by comparisons to predictions of models developed by ABS Consulting and Sandia for time dependent point releases from a draining tank, with and without burning. Simulations were in excellent agreement with those performed by ABS Consulting and consistent with Sandia's steady state results. To illustrate the model predictive capability for realistic emergency scenarios, simulations were performed for a tanker entering Block Island Sound. Three hypothetical cases were studied: the first assumes the vessel continues on course after the spill starts, the second that the vessel stops as soon as practical after the release begins (3 min), and the third that the vessel grounds at the closest site practical. The model shows that the areas of the surface pool and the incident thermal radiation field (with burning) are minimized and dispersed vapor cloud area (without burning) maximized if the vessel continues on course. For this case the surface pool area, with burning, is substantially smaller than for the without burning case because of the higher mass loss rate from the surface pool due to burning. Since the vessel speed substantially exceeds the spill spreading rate, both the thermal radiation fields and surface pool trail the vessel. The relative directions and speeds of the wind and vessel movement govern the orientation of the dispersed plume. If the vessel stops, the areas of the surface pool and incident radiation field (with burning) are maximized and the dispersed cloud area (without burning) minimized. The longer the delay in stopping the vessel, the smaller the peak values are for the pool area and the size of the thermal radiation field. Once the vessel stops, the spill pool is adjacent to the vessel and moving down current. The thermal radiation field is oriented similarly. These results may be particularly useful in contingency planning for underway vessels.
- Published
- 2007
- Full Text
- View/download PDF
3. Office managers' perception of stress, control, and satisfaction: a comparison between primary care and specialty practices.
- Author
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Chang JH, Whittier N, DeFries E, and Garfinkle A
- Subjects
- Adult, Attitude of Health Personnel, Humans, Middle Aged, Midwestern United States, Surveys and Questionnaires, Job Satisfaction, Medicine organization & administration, Nurse Administrators psychology, Practice Management, Medical, Primary Health Care organization & administration, Specialization, Stress, Psychological prevention & control
- Abstract
Perception of stress, control, and satisfaction was measured by office managers in medical practices. Office managers spend enormous amounts of time each day handling difficult interpersonal issues among staff physicians, and patients. As a group, physician disruptions were the most prevalent per day. Other staff members were considered the most stressful by rank order. Significant differences were discovered between primary care practices versus specialty practices in the areas of interactions with physicians.
- Published
- 2006
4. Estimation of potential impacts and natural resource damages of oil.
- Author
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McCay DF, Rowe JJ, Whittier N, Sankaranarayanan S, and Etkin DS
- Subjects
- Animals, Birds, California, Complex Mixtures, Costs and Cost Analysis, Environment, Environmental Exposure economics, Environmental Exposure prevention & control, Environmental Monitoring economics, Fishes, Food Chain, Fuel Oils toxicity, Hazardous Waste prevention & control, Invertebrates, Mammals, Models, Chemical, Risk Assessment economics, Risk Assessment methods, Ships, Water Pollution, Chemical analysis, Water Pollution, Chemical prevention & control, Conservation of Natural Resources economics, Ecology, Environmental Exposure adverse effects, Environmental Exposure analysis, Environmental Monitoring methods, Fuel Oils poisoning, Models, Biological
- Abstract
Methods were developed to estimate the potential impacts and natural resource damages resulting from oil spills using probabilistic modeling techniques. The oil fates model uses wind data, current data, and transport and weathering algorithms to calculate mass balance of fuel components in various environmental compartments (water surface, shoreline, water column, atmosphere, sediments, etc.), oil pathway over time (trajectory), surface distribution, shoreline oiling, and concentrations of the fuel components in water and sediments. Exposure of aquatic habitats and organisms to whole oil and toxic components is estimated in the biological model, followed by estimation of resulting acute mortality and ecological losses. Natural resource damages are based on estimated costs to restore equivalent resources and/or ecological services, using Habitat Equivalency Analysis (HEA) and Resource Equivalency Analysis (REA) methods. Oil spill modeling was performed for two spill sites in central San Francisco Bay, three spill sizes (20th, 50th, and 95th percentile volumes from tankers and larger freight vessels, based on an analysis of likely spill volumes given a spill has occurred) and four oil types (gasoline, diesel, heavy fuel oil, and crude oil). The scenarios were run in stochastic mode to determine the frequency distribution, mean and standard deviation of fates, impacts, and damages. This work is significant as it demonstrates a statistically quantifiable method for estimating potential impacts and financial consequences that may be used in ecological risk assessment and cost-benefit analyses. The statistically-defined spill volumes and consequences provide an objective measure of the magnitude, range and variability of impacts to wildlife, aquatic organisms and shorelines for potential spills of four oil/fuel types, each having distinct environmental fates and effects.
- Published
- 2004
- Full Text
- View/download PDF
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