Heavy-ion collisions at intermediate energies exhibit catastrophic phenomena which requires descriptions based on stochastic transport models. First, the Boltzmann-Langevin model, which provides an example of such stochastic approaches, is briefly described. Then, a projection method for obtaining numerical solutions of the Boltzmann-Langevin equation is discussed. Finally, some applications of the model to heavy-ion collisions are presented.

This report summarizes the progress made during the period May 1, 1993 through June 30, 1994 on Grant No. DE-FG05-92ER40694. Our calculations of M1 transition rates within rotational bands of superdeformed nuclei have been extended to 2-quasiparticle states (mainly for odd-odd nuclei) in the A {approx} 190 region. Several bands are predicted with large B(MI) values and suggest that the MI properties can give information on details of occupied single particle orbitals, alignment of some high-N particles and the residual two-body interactions at extreme deformation. Detailed calculations and comparison with UNISOR data for the low energy, low spin structure of {sup 187}Au have revealed two coexisting prolate structures built on the {pi}[h{sub 9/2} + f{sub 7/2}] configuration. This result was completely unexpected and presents strong challenges to our understanding of shape coexistence.

We briefly recall the Boltzmann-Langevin model of nuclear dynamics. We then summarize recent progress in deriving approximate analytical expressions for the associated transport coefficients and describe a numerical method for simulating the stochastic evolution of the phase-space density.

Top address a growing national problem with generation of wastes and by-products, TVA has been involved for several years with developing and commercializing environmentally responsible practices for eliminating, minimizing, or utilizing various wastes/by-products. In many cases, reducing waste generation is impractical, but the wastes/by-products can be converted into other environmentally sound products. In some instances, conversion of safe, value-added agricultural products in the best or only practical alternative. TVA is currently involved with a diversity of projects converting wastes/by-products into safe, economical, and agriculturally beneficial products. Environmental improvement projects have involved poultry litter, cellulosic wastes, used battery acid, ammonium sulfate fines, lead smelting effluents, deep-welled sulfuric acid/ammonium bisulfate solutions, wood ash, waste magnesium ammonium sulfate slurry from recording tape production, and ammunition plant waste sodium nitrate/ammonium nitrate streams.

A process for oxidizing aqueous elemental phosphorus containing residues (sludges) to produce orthophosphate containing slurries suitable for subsequent reaction with ammonia to produce nitrogen and phosphate containing fertilizer products is presented. It comprises reacting aqueous elemental phosphorus containing residues with certain special mixtures of concentrated nitric acid and sulfuric acid to effect the conversion of the elemental phosphorus into mostly orthophosphoric acid and very little orthophosphorus acid with the relative ratios of the two acids being dependent upon the mole ratio of H{sub 2}SO{sub 4}:HNO{sub 3} employed in the processing. The resulting aqueous reaction intermediate is neutralized with ammonia during processing to a fluid or solid fertilizer product. Prior to the conversion to products, the aqueous reaction intermediate may be subjected to a solids separation step to remove insoluble salts of certain environmentally undesirable metals, such as Pb, Cd, Ba, and Cr.

During most of the 60 years that TVA has been in existence, the research center at Muscle Shoals, Alabama, NERC, was charged with supporting the regional and national agribusiness industry. One aspect of this support was strong emphasis on fertilizer process and product development. One such product developed at the center was a liquid fertilizer with a grade of 10-34-0 (N-P{sub 2}0{sub 5}-K{sub 2}0). The process was profitable and easy to operate, the product was well accepted by both farmers and dealers, and 10-34-0 became the premium phosphate fertilizer used in the United States. Approximately 120 to 130 of these type units have been constructed and operated in the United States in the last 20 years. During that time, the process design has remained essentially unchanged. The direct contact between the hot fertilizer product and the air results in some free ammonia being stripped from the product and emitted from the top of the cooling tower. At the time most of the plants were constructed, there was little concern over these losses because (1) there were very few regulations dealing with ammonia and (2) most of the plants were originally built and operated in rural areas away from population centers …

Laboratory investigation has been undertaken to determine the electrochemical behavior and corrosion resistance of various construction materials in a simulated hydrolysis environment (5 wt % sulfuric acid) at temperatures ranging from 90 to 220C. Tests were performed in an autoclave-type electrochemical cell. The corrosion behavior of the test materials was determined using computer-controlled DC potentiodynamic polarization. Corrosion rates of the test materials were determined using AC impedance techniques. Among the stainless steels tested, only alloy N08026 (Carpenter 20Mo-6) performed satisfactory up to a temperature of 100C. The alloy passivated spontaneously in the environment and corroded at a rate of less than 2 mpy. None of the stainless steels tested could be used at 120{degrees}C or above. A number of nickel-based alloys tested had good corrosion resistance up to 100C, but their corrosion rate exceeded 2 mpy at higher temperatures. Zirconium alloys were satisfactory up to 180C. Only tantalum and a tantalum-niobium alloy were satisfactory up to 220C.

TiO{sub 2} photocatalysis is investigated is a potential means for the disposal of pesticide rinsate waste at agrochemical dealerships. The focus is an evaluation of parameters that affect the rate and mechanism of atrazine degradation using formulated atrazine (ca. 20-25 ppm), TiO{sub 2} mesh, a high-pressure mercury-vapor lamp, and solar irradiation. The UV transmission of a variety of transparent materials was measured and atrazine photocatalysis was carried out using several materials as reactor covers. The pseudo-first-order rate constants were calculated and compared to determine which cover results in the most efficient atrazine degradation. A clear acrylic gave results nearly identical to Pyrex and was chosen for future photocatalytic experiments. UV intensity and photocatalytic rate were studied as a function of different numbers of layers of TiO{sub 2} mesh. It was found that five layers give the optimum rate of degradation without employing excess mesh. In order to assess the general effect of impurities present in water on the rate of atrazine degradation, water from five different sources was obtained and each sample was analyzed for purity and used to prepare aqueous atrazine for photocatalytic degradation. The results show that contaminants specific to different locations are likely to inhibit the rate …

This article looks at the US fertilizer industry covering the following topics: phosphate mining, basic integrated production, retail dealers, and farm practices. At each point the impact of environmental concerns and compliance on the fertilizer industry is discussed.

The Tennessee Valley Authority`s Environmental Research Center has been developing a means of detoxifying atrazine waste waters using TiO{sub 2} photocatalysis. The toxicity and physical properties of atrazine and its degradation products will probably be required information in obtaining permits from the United States Environmental Protection Agency for the demonstration of any photocatalytic treatment of atrazine waste waters. The following report is a literature survey of the toxicological and physical properties of atrazine and its degradation products.

Work using a low-temperature concentrated sulfuric acid hydrolysis process to convert the cellulosic fraction of corn stover to monomeric sugars demonstrated the high conversion efficiencies possible with that process. The TVA work also confirmed the need for a cost-effective acid-sugar separation process. A preparative-scale ion-exclusion chromatography (IEC) system was designed, constructed, and tested with a variety of synthetic solutions and actual hydrolyzates. Although significant dispersion was observed initially, design changes were effective in minimizing this phenomenon. Data collected during the operation of the preparative-scale system were used in the design and construction of an IEC miniplant capable of processing larger volumes of synthetic solutions or hydrolyzates and in the design of an extraction-assisted IEC system. The data were also used to assess the viability of a continuous feed IEC system. This paper includes a discussion of the IEC process, provides overall material balances for various IEC process scenarios, and presents a discussion on process economics.

Corrosion tests were performed with various construction materials, such as carbon steel, cast iron, stainless steels, nickel and nickel-based alloys, copper and its alloys, aluminum alloy, zirconium alloy, and tantalum, exposed to wet-process superphosphoric acids (approximately 70% P{sub 2}O{sub 5}) from all the suppliers in the United States and to a technical-grade (55% P{sub 2}O{sub 5}) acid made by the electric furnace process. The study was conducted in response to reports from pipe-reactor users of excessive corrosion by superphosphoric acids and electric furnace acid. Test temperatures were ambient (approximately 21{degrees}C or 70{degrees}F), 66{degrees}C (150{degrees}F), and 93{degrees}C (200{degrees}F). Test results showed that temperature was a significant factor in acid corrosivity. Electric furnace acid was more corrosive than the superphosphoric acids. Carbon steel, cast iron, and aluminum alloy were not resistant to either the superphosphoric acids or the electric furnace acid. Nickel-chromium (Ni-Cr) and nickel-molybdenum (Ni-Mo) based alloys and tantalum exhibited adequate corrosion resistance in the superphosphoric acids and the electric furnace acid. Stainless steels performed well in all test acids at all test temperatures with some exceptions in the electric furnace acid at 93{degrees}C. Zirconium alloy, copper and its alloys, pure nickel, and Monel 400 provided adequate corrosion resistance to all …

The optimization of a technology for the TiO{sub 2}-mediated solar photocatalysis of atrazine is described. The target users of this technology might be agrochemical dealers, manufacturers, and possibly farmers. Studies were performed to determine the ideal cover material for such a reactor based on UV light transmitting properties. The best cover material was a UV transmitting acrylic. The TiO{sub 2} employed for this technology was bound to fiberglass mesh. The effects of mesh amount, stirring, water impurities, concentration of pesticide, and source of UV light (mercury vapor lamp vs. solar) were also determined. The most efficient photocatalysis was achieved using five layers of mesh, a stirred reaction, water low in carbonate and other ions, a dilute waste stream, and solar irradiation rather than a mercury-vapor lamp. The formation and disappearance of eight intermediates were followed in a 2429 h indoor experiment comparing pure and formulated atrazine. A modified reaction mechanism was proposed based on studies of the detected intermediates.

The development of a concentrated acid hydrolysis process may necessitate the storage, handling, and processing of concentrated solution of sulfuric acid at temperatures in excess of 70{degrees}C. Due to the corrosivity of the sulfuric acid at elevated temperatures, a series of corrosion tests was conducted to determine the corrosion performance and behavior of various construction materials using immersion and electrochemical techniques. Test results showed that among the stainless steels tested, only Carpenter 20Mo-6 performed satisfactorily up to 70{degrees}C. It passivated spontaneously and corroded at a rate less than 40 {mu}m/yr (1.6 mpy). Among numerous nickel-based alloys tested, only Hastelloy B-2 had excellent corrosion resistance up to 100{degrees}C with a corrosion rate less than 50 {mu}/yr (2 mpy), although the alloy did not passivate. Zirconium alloy Zr 702 provided excellent corrosion resistance to 100{degrees}C. The alloy passivated spontaneously, but its passive range decreased, evidently with increase in temperature. Tantalum and KBI-40 provided excellent corrosion protection at all test temperatures. The materials passivated spontaneously with a wide passive range.

Published by TVA, this data summary gives fertilizer consumption patterns, crop acreage, application rates, and farm income and expense data by state and region for select years from 1970 to 1992.

This is a continuation of corrosion studies on the effectiveness of commercial and newly-developed corrosion inhibitors for use with mild steel exposed to urea-ammonium nitrate (UAN) solution. This paper provides updated information on five newly-developed corrosion inhibitors. Tests were conducted with mild steel exposed to 32-0-0 UAN solution containing each corrosion inhibitor at ambient temperature and under static conditions. Real-time corrosion of the test specimens was monitored using AC impedance techniques. Corrosion performance of the inhibitors was evaluated based on comparison of the corrosion rate of specimens exposed to 32-0-0 UAN solution with and without a corrosion inhibitor.

Public Support for the Tennessee Valley Authority`s (TVA) fertilizer research and development program in Muscle Shoals, Alabama, ended in fiscal year 1993. TVA`s research center at Muscle Shoals, formerly known as the National Fertilizer and Environmental Research Center, is now the TVA Environmental Research Center. Efforts at the Center have diversified to include research and support areas of Agricultural Research and Practices, Atmospheric Sciences, Biotechnology, Waste Management, and Remediation, Environmental Site Remediation, Support Services, Environmental Management, and Technology Transfer. ``We`re building on the expertise and success of our earlier research and focusing our new projects on emerging problems of the 21st century,`` TVA`s Chairman Craven Crowell said in prepared remarks to Congress on March 2, 1994. Agricultural Research in TVA has been aligned with corporate objectives to develop solutions to environmental problems of regional, national and international significance because the agency`s business incorporates a broad mix of responsibilities, including power generation, navigation, flood control, shoreline management, recreation, environmental research, and economic development. Agricultural strategies for watershed protection lie at the core of TVA`s new agricultural research agenda. The major influences for this agenda are TVA`s direct stewardship responsibilities for the 60,000 miles of streams that feed the 652-mile-long Tennessee River; …

An ultra sensitive technique for the detection of fluorescent species in a flowing stream has been developed. The extension of this technique to the detection of fluorescently tagged nucleotides will be a significant benefit to one of the novel approaches for DNA sequencing being developed at Los Alamos National Laboratories. The detection scheme is based on a novel mode of operating a Charge-Coupled Device (CCD) which greatly enhances the discrimination between fluorescence from the analyte and the background Raman scattering from the solvent. Register shifts between rows in the CCD are synchronized with the sample flow velocity so that fluorescence from a single species is collected in a single moving charge packet occupying an area approaching that of a single pixel while the background is spread evenly among a large number of pixels. This research has demonstrated that this technique is highly effective for the detection of fluorescently labelled latex microspheres. With additional development, the authors believe that this technique will achieve single molecule detection.

The Alabama Universities/Tennessee Valley Authority Research Consortium (AUTRC), established in 1985, includes two state agencies and one federal agency working cooperatively with seven Alabama public research institutions to promote research and support economic development in Alabama. In 1985 the Alabama Department of Economic and Community Affairs (ADECA) was awarded a grant from the Appalachian Regional Commission (ARC) to establish a consortium of research universities and promote the economic development of the Appalachian counties of north Alabama. The following year, the Alabama Commission on Higher Education (ACHE) requested funding from the state legislature (Special Educational Trust Fund) to provide continuing support for AUTRC. One of the principal goals of this Consortium was to facilitate job creation in the state through the commercialization of TVA research. Since that time, continuing appropriations from ACHE and support from TVA, the universities, and the private sector have continued to support research activities and commercialization efforts. This report provides a ten-year overview of the program`s evolution, describes its research and commercialization activities, identifies the roles and contributions of the parties to the Consortium, and presents conclusions and recommendations for the future.

This report summarizes the results of Task 9 of the TVA/Department of Energy (DOE) Interagency Agreement supporting DOE`s Clinch River Remedial Investigation. Species lists and densities (numbers/m{sup 2}) of benthic macroinvertebrates sampled at 16 sites in the Clinch River and Poplar Creek embayments of upper Watts Bar Reservoir near Oak Ridge, Tennessee, in March, 1994, are presented and briefly discussed. Data are also analyzed to assess and compare quality of benthic communities at each site, according to methods developed for TVA`s Reservoir Vital Signs Monitoring Program. Results of this study will be incorporated with other program tasks in a comprehensive report prepared by Oak Ridge National Laboratory in 1995, which will, in part, assess the effect of sediment contaminants on benthic macroinvertebrate communities in Watts Bar Reservoir.