[en] Straw color may alter the net radiative flux at the soil-straw surface and, consequently, the availability of energy for soil, biological, and atmospheric processes. This study ascertained the radiation balance of a soil-straw surface as modified by the color of the straw on the surface. Barley (Hordeum vulgare L.) stubble and loose straw on 36-m² plots near Fairbanks, AK, was painted black, white, or remained unpainted (natural) in a randomized block experimental design. Reflected global radiation was measured in the spring of 1988–1990 and net radiation was monitored in the spring of 1990. Midday reflected global radiation and soil-straw surface temperatures were measured on clear days in 1989. The albedo of the black straw treatment was 0.05, of the natural straw treatment was 0.2, and of the white straw treatment was 0.3. The black straw treatment resulted in higher midday surface temperatures and consequently higher emission of longwave radiation compared with other straw color treatments. A soilstraw-atmosphere system model provided good estimates of the measured net radiative flux in 1990 (R² = 0.91). The model predicted that a soil-black straw surface would absorb 10% more radiation than a soil-natural straw surface and 15% more radiation than a soil-white straw surface averaged over the three years. The results suggest that straw color management can be an option for altering the surface radiation balance in regions with extreme climates. (author)

No abstract available

No abstract available

[en] This report contains results of model validation studies conducted by Pacific Northwest Laboratory (PNL) for the Department of Energy's (DOE) National Low Level Waste Management Program (NLLWMP). The model validation tests consisted of using unsaturated water flow models to simulate water balance experiments conducted at the Buried Waste Test Facility (BWTF) located at the Department of Energy's Hanford site, near Richland, Washington. The BWTF is a lysimeter facility designed to collect field data on long-term water balance and radionuclide tracer movement. It has been operated by PNL for the NLLWMP since 1978. An experimental test case, developed from data collected at the BWTF, was used to evaluate predictions from different water flow models. The major focus of the validation study was to evaluate how the use of different evaporation models affected the accuracy of predictions of evaporation, storage, and drainage made by the whole model. Four evaporation models were tested including two empirical models and two mechanistic models. The empirical models estimate actual evaporation from potential evaporation; the mechanistic models describe water vapor diffusion within the soil profile and between the soil and the atmosphere in terms of fundamental soil properties, and transport processes. The water flow models that included the diffusion-type evaporation submodels performed best overall. The empirical models performed poorly in their description of evaporation and profile water storage during summer months. The predictions of drainage were supported quite well by the experimental data. This indicates that the method used to estimate hydraulic conductivity needed for the Darcian submodel was adequate. This important result supports recommendations for these procedures that were made previously based on laboratory results

[en] In shallow land burial, the most common disposal method for low-level waste, waste containers are placed in shallow trenches and covered with natural sediment material. To design such a facility requires an in-depth understanding of the infiltration and evaporation processes taking place at the soil surface and the effect these processes have on the amount of water cycling through a burial zone. At the DOE Hanford Site in Richland, Washington, a field installation called the Buried Waste Test Facility (BWTF) has been constructed to study unsaturated soil water and contaminant transport. PNL is collecting data at the BWTF to help explain soil water movement at shallow depths, and specifically evaporation from bare sols. The data presented here represent the initial phase of a cooperative effort between PNL and Washington State University to use data collected at the BWFT to study the evaporated process and how it relates to the design of shallow land burial grounds. The method of chthe fraction of a specific element leached can be determined al half-lives with experimental ones, over a range of 24 orders of magnitude was obtained. This is a strong argument that the alpha decay could be considered a fission process with very high mass asymmetry and charge density asymmetry

[en] Radiative exchange at the soil surface can be altered by the surface configuration. Tillage methods that modify the soil surface for increased radiation absorption are needed in the subarctic, where soil temperature is a limiting factor in crop adaptation and production. The radiation climate of ridge-tillage was investigated to determine the optimum ridge aspect and slope for maximizing radiation absorption on soils in the subarctic. Comparisons of net radiation (Rn), albedo, and soil surface temperatures were made on ridge plots (6.1 by 6.1 m); with ridges oriented northeast-southwest, northwest-southeast, east-west, and north-south; and a horizontal surface during the 1988 through 1990 growing seasons at Fairbanks, AK. A radiation-balance model of ridged surfaces was developed to ascertain localized irradiance and isothermal net radiation (Rn) effects owing to slope and aspect of ridges. Measured Rn differences were found at midday on clear days when Rn was about 30 W m-2 higher on ridged than horizontal surfaces. The higher Rn resulted from a lower albedo and lower soil surface temperatures of the ridged surfaces. Modeled irradiance on ridges used in this study agreed well with measured values. Modeled Rni results using four seasons of micrometeorological data suggested that southerly aspects inclined 20 to 40 degrees offered the greatest advantage in radiation absorption at Fairbanks

[en] The authors are attempting to clone the genes coding for amino acid transport System L. Chinese hamster ovary (CHO) cell mutants that are temperature sensitive in their leucyl-tRNA synthetase show temperature-dependent regulation of System L. Temperature resistant mutants isolated from these cells have constitutively derepressed System L activity. Somatic cell fusion studies using these mutants have suggested that a trans-acting element controls regulation of System L. Mutants with reduced transport activity were isolated by a ³H-suicide selection. The growth of these mutant cells is limited by the transport defect. CHO mutants were transformed with a human cosmid library, followed by selection at high temperatures and low leucine concentrations. Some transformants have increased levels of System L activity, suggesting that human genes coding for leucine transport have been incorporated into the CHO genome. Human sequences were rescued by a lambda in vitro packaging system. These sequences hybridize to vector and total human DNA. Experiments are being done to confirm that these sequences indeed code for transport System L. They are also attempting to label membrane components of amino acid transporters by group-specific modifying reagents

[en] A simulation model was developed by mass and energy balance in one dimension to predict field nitrogen and potassium leaching in a soil (a fine mixed Mesic Tropudult) under a mature tea with high levels of nitrogen and potassium applications. The model was corroborated by field measurements of soil moisture, yield and N and K leaching in a long term fertilizer experiment. The model prediction agreed reasonably well with the measured values in the field under different levels of nitrogen and potassium applications. (author). 17 refs, 3 figs, 3 tabs

[en] Based on our experience with four cases of liver cysts and review of the literature, the following conclusions are reached: (1) Diagnosis can be established with routine and special radiologic studies. (2) Laparotomy is indicated for patients with symptoms or uncertain diagnosis. (3) Surgical management should be guided by cyst size, location, and content. (4) Definitive surgical treatment is indicated only for cysts larger than 10 cm