Twenty young healthy dogs weighing from 9.8 to 28.6 kg were studied by M‐mode echocardiography. Parameters were measured and statistically evaluated to determine whether a correlation to body surface area existed. A statistically significant correlation to body size was found for the aortic, left atrial, left ventricular, septal, and posterior wall dimensions and the mitral valve amplitude of motion. In addition, normal values not correlated to body surface area are presented with their means and standard deviations. These values include velocity of circumferential fiber shortening, ejection time, percent systolic thickening of septum and posterior wall, percent change in minor diameter, selected dimension ratios, and mitral valve velocities
The AIRDOS-EPA computer code is a methodology, designed for use on IBM-360 computers, that estimates radionuclide concentrations in air; rates of deposition on ground surfaces; ground surface concentrations; intake rates via inhalation of air and ingestion of meat, milk, and fresh vegetables; and radiation doses to man from airborne releases of radionuclides. This report describes the atmospheric and terrestrial transport models used in the code, their computer implemetation, and the applicability of the code to the assessment of radiological impacts. A listing of the code and a demonstration run of the code are presented in the appendices.
The objectives of the Model Validation Committee were to collaborate with US and foreign scientists to collect, manage, and evaluate data for identifying critical research issues and data needs to support an integrated assessment of the Chernobyl nuclear accident; test environmental transport, human dosimetric, and health effects models against measured data to determine their efficacy in guiding decisions on protective actions and in estimating exposures to populations and individuals following a nuclear accident; and apply Chernobyl data to quantifications of key processes governing the environmental transport, fate and effects of radionuclides and other trace substances. 55 refs.
AIRDOS-EPA estimates radionuclide concentrations in air; rates of deposition on ground surfaces; ground surface concentrations; intake rates via inhalation of air and ingestion of meat, milk, and fresh vegetables; and radiation doses to man from airborne releases of radionuclides. The program may be run to estimate either the highest annual individual dose in the area or the annual population dose. For either option, output tables summarize doses by nuclide, exposure mode, and organ. Using either a square or circular grid option, ground concentrations of radionuclides and intake rates by man are tabulated for selected environmental locations in the area surrounding the source. Working level exposures for inhalation of radon-222 short-lived progeny are tabulated also.
After radionuclides are deposited on vegetation, environmental removal processes combine with radioactive decay to reduce the quantity of initial contamination. The time in which one-half of the radioactivity is removed from vegetation by environmental processes alone is referred to as the environmental half time, Tw. For long-lived radionuclides, the dose to man via ingestion of contaminated terrestrial foods may be directly influenced by values of Tw, provided that environmental removal processes dominate root uptake and time is sufficiently long between initial exposure of vegetation and harvest. Values of Tw reported in the literature for various radionuclides and methods of deposition are examined. Factors affecting the variability of Tw are related in part to the physicochemical form of the depositing substance, vegetation type and growth form, climate, season, and experimental procedure. For growing vegetation, values of Tw are generally lower than those reported for dormant vegetation. Values of Tw for iodine vapor and iodine particulate are less than values of Tw reported for particulates of other elements. Values of Tw determined on a per unit vegetation mass basis are also less than values of Tw determined on a per unit ground area basis, the differences being attributable to the effects of growth dilution. Although an assessor has a range from which to select a value of Tw for the purpose of estimating contamination by long-lived radionuclides, the variability in Tw is small in comparison to many other parameters used in environmental radiological assessments.
Groundwater contamination by hexavalent chromium and other nuclear reactor operation-related contaminants has resulted in the need for groundwater remedial actions within the Hanford Site reactor areas (the Hanford Site 100 Area). The large geographic extent of the resultant contaminant plumes requires an extensive level of understanding of the aquifer structure, characteristics, and configuration to support assessment and design of remedial alternatives within the former 100-D, 100-H, and 100-K reactor areas. The authors have prepared two- and three-dimensional depictions of the key subsurface geologic structures at two Hanford Site reactor operable units (100-K and 100-D/H). These depictions, prepared using commercial-off-the-shelf (COTS) visualization software, provide a basis for expanding the understanding of groundwater contaminant migration pathways, including identification of geologically-defined preferential groundwater flow pathways. These identified preferential flow pathways support the conceptual site model and help explain both historical and current contaminant distribution and transport. (authors)
The advantages of a fluid-bed furnace are chemistry-based. The particles are exposed completely to the gas that they are being fluidized in. Reactions that are occurring can propagate at a slightly enhanced rate because there are no gases, such as carbon monoxide, retarding the reaction. These particles move very quickly from the bed, rather than having a static bed condition. It helps reduce agglomeration, which can occur when particles in contact continually agitate the particles in a controlled manner. The negatives of the system are that operations are in atmospheric conditions or higher. Higher pressures are also possible, but difficult because the particles are so small.
The Savannah River Laboratory is in the process of conducting a series of atmospheric tracer studies. The inert gas sulfurhexafluoride is released from a height of 62 m for 15 min and concentrations in air are measured on sampling arcs up to 30 km downwind of the release point. Maximum 15 min. air concentrations from 14 of these tracer tests have been compared with the ground-level, centerline air concentration predicted with a Gaussian plume atmospheric transport model using eight different sets of atmospheric dispersion parameters. Preliminary analysis of the results from these comparisons indicates that the dispersion parameters developed at Juelich, West Germany, based on tracers released from a height of 50 m, give the best overall agreement between the predicted and observed values. The median value of the ratio of predicted to observed air concentrations for this set of parameters is 1.3, and the correlation coefficient between the log of the predictions and the log of the observations is 0.72. For the commonly used Pasquill-Gifford dispersion parameters, the values of these same statistics are 4.4 and 0.68, respectively. The Gaussian plume model is widely used to predict air concentrations resulting from short-term radionuclide release to the atmosphere. The resultsmore » of comparisons such as these must be considered whenever the Gaussian model is used for such purposes. 22 references, 3 tables.« less
