Diagnostic studies of climate variability. Annual report, December 1, 1991--November 30, 1992 (open access)

Diagnostic studies of climate variability. Annual report, December 1, 1991--November 30, 1992

This paper reports on the progress on the first year of the diagnostic studies of climate variability project. The objectives were as follows: to initiate studies of long-term climatic variability, using long instrumental data sets, and proxy records; to examine regional changes of temperature and precipitation over the past century in relation to changes at the hemispheric and global scale; and to produce a map-based archive of monthly and seasonal temperature, precipitation and pressure data fore display on PCs. Significant progress has been made in all of these areas. This paper summarizes results of the work accomplished. Part A summarizes results of the work accomplished. Part A summarizes the work accomplished primarily at the University of Massachusetts. Part B summarizes work primarily conducted at NOAA/ERL. A list of papers published, in press, or in preparation then follows. Appendix 1 is a description of the proposed research in 1992--93, and a proposed budget.
Date: November 1, 1992
Creator: Bradley, R. S. & Diaz, H. F.
Object Type: Report
System: The UNT Digital Library
Bacterial chromate reduction and product characterization (open access)

Bacterial chromate reduction and product characterization

Bacillus subtilis reduced hexavalent chromate to trivalent chromium under either aerobic or anaerobic conditions. Reduction of CR(VI) and appearance of extracellular Cr(III) were demonstrated by electron spin resonance and spectrophotometry. Chromate reduction was stimulated more than five-fold by freeze-thawing, indicating that intracellular reductases or chemical reductants reduce chromate more rapidly than do intact cells. Moderately concentrated cells (10% pellet volume after centrifugation) reduced approximately 40 {mu}M chromate/min (2 mg Cr/1-min) when exposed to 100 {mu}M chromate (5 mg Cr/1). Highly concentrated cells (70% pellet volume) reduced more than 99.8% of 2 mM chromate (100 mg Cr/1) within 15 min. This rate of chromate reduction was of the same order of magnitude as the rate of respiration in aerobic cells. A substantial fraction of the reduction product (ca. 75%) was extracellular Cr(M), which could readily be separated from the cells by centrifugation. At high chromate concentrations, some fraction of reduced CR(VI) appeared to be taken up by cells, consistent with a detection of intracellular paramagnetic products. At low chromate concentrations, undefined growth medium alone reduced Cr(VI), but at a slow rate, relative to cells. Under appropriate conditions, B. subtilis appears to be an organism of choice for detoxifying chromate-contaminated soil and …
Date: November 1, 1992
Creator: Mehlhorn, R. J.; Buchanan, B. B. & Leighton, T.
Object Type: Article
System: The UNT Digital Library
A study of a tissue equivalent gelatine based tissue substitute (open access)

A study of a tissue equivalent gelatine based tissue substitute

A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it`s usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.
Date: November 1, 1992
Creator: Spence, J. L.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A study of a tissue equivalent gelatine based tissue substitute (open access)

A study of a tissue equivalent gelatine based tissue substitute

A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it's usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.
Date: November 1, 1992
Creator: Spence, Jody L.
Object Type: Report
System: The UNT Digital Library
Biological assessment for the remedial action at the chemical plant area of the Weldon Spring site (open access)

Biological assessment for the remedial action at the chemical plant area of the Weldon Spring site

The Weldon Spring site in St.Charles County, Missouri, became contaminated during the 1940s through the 1960s as a result of explosives production by the US Army and uranium and thorium processing by the predecessor agency of the US Department of Energy (DOE). The site is listed on the National Priorities List of the US Environmental Protection Agency, and DOE is responsible for its cleanup. Contaminants are present in soil, surface water, and aquatic sediments. Alternatives identified for site remediation are no action (included as baseline for comparison), treatment and disposal of the wastes at the Weldon Spring site, and on-site treatment followed by off-site disposal at either a commercial facility near Clive, Utah, or at DOE's Hanford site near Richland, Washington. In accordance with the requirements of the Endangered Species Act, this biological assessment has been prepared to evaluate the potential effects of proposed remedial action alternatives on federal listed (endangered or threatened) and candidate species at the respective sites. The assessment includes consideration of the environmental setting at each site; the federal listed and candidate species that could occur at each site; the construction, excavation, and treatment activities under each alternative; and the amount of land area affected at …
Date: November 1, 1992
Creator: Hlohowskyj, I. & Dunn, C. P.
Object Type: Report
System: The UNT Digital Library
Biological assessment for the remedial action at the chemical plant area of the Weldon Spring site (open access)

Biological assessment for the remedial action at the chemical plant area of the Weldon Spring site

The Weldon Spring site in St.Charles County, Missouri, became contaminated during the 1940s through the 1960s as a result of explosives production by the US Army and uranium and thorium processing by the predecessor agency of the US Department of Energy (DOE). The site is listed on the National Priorities List of the US Environmental Protection Agency, and DOE is responsible for its cleanup. Contaminants are present in soil, surface water, and aquatic sediments. Alternatives identified for site remediation are no action (included as baseline for comparison), treatment and disposal of the wastes at the Weldon Spring site, and on-site treatment followed by off-site disposal at either a commercial facility near Clive, Utah, or at DOE`s Hanford site near Richland, Washington. In accordance with the requirements of the Endangered Species Act, this biological assessment has been prepared to evaluate the potential effects of proposed remedial action alternatives on federal listed (endangered or threatened) and candidate species at the respective sites. The assessment includes consideration of the environmental setting at each site; the federal listed and candidate species that could occur at each site; the construction, excavation, and treatment activities under each alternative; and the amount of land area affected at …
Date: November 1, 1992
Creator: Hlohowskyj, I. & Dunn, C. P.
Object Type: Report
System: The UNT Digital Library
Supplement to a hydrologic framework for the Oak Ridge Reservation, Oak Ridge, Tennessee (open access)

Supplement to a hydrologic framework for the Oak Ridge Reservation, Oak Ridge, Tennessee

The information in this report should prove useful for flow and contaminant-transport modeling of groundwater and for evaluating the alternatives for remedial action. New data on porosity and permeability have been analyzed and interpreted to produce a better understanding of the relationships between unfractured rock, low permeability intervals, and relatively permeable intervals. Specifically, the dimensions, orientations, depths, and spacings of pervious fractures have been measured or calculated; the depths and directions of subsurface flow paths (Solomon et al. 1992, pp. 3--21 to 3--23) have been corroborated with new data; fractures near the water table have been shown to have different characteristics than those at deeper levels; and the relationships between groundwater flows in fractures and flows in the continuum have been described. This is the information needed for the numerical modeling of groundwater flows. Other information in this report should result in a better understanding of spatial and temporal differences in water chemistry, including changes in contaminant concentrations. Temporal changes in groundwater chemistry have been shown to occur mostly near the water table. These changes consist of a periodic dilution of chemical constituents by recharge and a slow increase in constituent concentrations between recharge events. At discharge locations, spatial differences …
Date: November 1, 1992
Creator: Moore, G.K. (Tennessee Univ., Knoxville, TN (United States). Dept. of Civil Engineering) & Toran, L.E. (Oak Ridge National Lab., TN (United States))
Object Type: Report
System: The UNT Digital Library
Supplement to a hydrologic framework for the Oak Ridge Reservation, Oak Ridge, Tennessee. Summary of groundwater modeling (open access)

Supplement to a hydrologic framework for the Oak Ridge Reservation, Oak Ridge, Tennessee. Summary of groundwater modeling

The information in this report should prove useful for flow and contaminant-transport modeling of groundwater and for evaluating the alternatives for remedial action. New data on porosity and permeability have been analyzed and interpreted to produce a better understanding of the relationships between unfractured rock, low permeability intervals, and relatively permeable intervals. Specifically, the dimensions, orientations, depths, and spacings of pervious fractures have been measured or calculated; the depths and directions of subsurface flow paths (Solomon et al. 1992, pp. 3--21 to 3--23) have been corroborated with new data; fractures near the water table have been shown to have different characteristics than those at deeper levels; and the relationships between groundwater flows in fractures and flows in the continuum have been described. This is the information needed for the numerical modeling of groundwater flows. Other information in this report should result in a better understanding of spatial and temporal differences in water chemistry, including changes in contaminant concentrations. Temporal changes in groundwater chemistry have been shown to occur mostly near the water table. These changes consist of a periodic dilution of chemical constituents by recharge and a slow increase in constituent concentrations between recharge events. At discharge locations, spatial differences …
Date: November 1, 1992
Creator: Moore, G. K. & Toran, L. E.
Object Type: Report
System: The UNT Digital Library