The primary objective of the collaborative studies with EITU was to study curium bismuthide using energy dispersive X-ray diffraction to monitor its structure as a function of pressure. This objective was accomplished and the material was investigated up to 0.48 megabars of pressure. These studies were a continuation of established and productive collaborations between ORNL and EITU. The study of this curium compound is significant in that it is the first 5f-element bismuthide to be studied under pressure. Bismuth has the highest Z and the largest radius of the pnictogen group of elements (important for Hill Plot assessments) and has the greatest potential to form f-p type bonding with actinides under pressure. From a preliminary assessment of our experimental data it has been determined that two structural transitions occurred in the curium bismuthide sample as a result of the applied pressure.

The countercurrent flow (CCF) performance in the fuel element region of the HFIR is examined experimentally and theoretically. The fuel element consists of two concentric annuli filled with aluminum clad fuel plates of 1.27 mm thickness separated by 1.27 mm flow channels. The plates are curved as they go radially outward to accomplish constant flow channel width and constant metal-to-coolant ratio. A full-scale HFIR fuel element mock-up is studied in an adiabatic air-water CCF experiment. A review of CCF models for narrow channels is presented along with the treatment of CCFs in system of parallel channels. The experimental results are related to the existing models and a mechanistic model for the annular'' CCF in a narrow channel is developed that captures the data trends well. The results of the experiment are used to calculate the CCFL heat flux of the HFIR fuel assembly. It was determined that the HFIR fuel assembly can reject 0.62 Mw of thermal power in the CCFL situation. 31 refs., 17 figs.

Creating low-energy electrons in the stratosphere by photoelectric emission has the beneficial effect of suppressing ozone destruction by Cl. This is because Cl is converted to Cl{sup {minus}}, which is less reactive. Critical to the success of this scheme is the ability to attach most of the electrons to Cl{sup {minus}} and its hydrates Cl{sup {minus}} (H{sub 2}O). We found that this attachment efficiency is rather high. This is remarkable given the fact that the electron affinity of Cl{sup {minus}} is less than that of NO{sub 3}{minus}. Photoddetachment of NO{sub 3}{minus} is the key factor that leads to this high efficiency. Computer calculations show that ozone increases with electron injection, and most of the electrons end up attaching to Cl{sup {minus}}(H{sub 2}O). We also point out that 40 km, the altitude at which most of the ozone destruction occurs, is also the optimum altitude for injecting photoelectric electrons. 12 refs., 6 figs.

This report discusses the following topics in relationships to plasma simulation: unstructed grids; particle tracking; and field propagation. (LSP)

The traveler participated in a conference on environmental technology in Paris, sponsored by the US Embassy-Paris, US Environmental Protection Agency (EPA), the French Environmental Ministry, and others. The traveler sat on a panel for environmental aspects of energy technology and made a presentation on the potential contributions of Oak Ridge National Laboratory (ORNL) to a planned French-American Environmental Technologies Institute in Chattanooga, Tennessee, and Evry, France. This institute would provide opportunities for international cooperation on environmental issues and technology transfer related to environmental protection, monitoring, and restoration at US Department of Energy (DOE) facilities. The traveler also attended the Fourth International Conference on Environmental Contamination in Barcelona. Conference topics included environmental chemistry, land disposal of wastes, treatment of toxic wastes, micropollutants, trace organics, artificial radionuclides in the environment, and the use biomonitoring and biosystems for environmental assessment. The traveler presented a paper on The Fate of Radionuclides in Sewage Sludge Applied to Land.'' Those findings corresponded well with results from studies addressing the fate of fallout radionuclides from the Chernobyl nuclear accident. There was an exchange of new information on a number of topics of interest to DOE waste management and environmental restoration needs.

The objective of this travel was to advance provisional planning of an activity to coordinate research and development (R D) activities on fusion materials among the existing fusion materials R D programs of the ITER parties. This objective was accomplished in discussions with the Executive Committee for the IEA Implementing Agreement on Fusion Materials in Karlsruhe, Germany, and with the ITER management and staff of Garching, Germany. The IEA Executive Committee deferred substantive consideration of the topic at the insistence of the Ex-Officio member from European Community (EC), Brussels. Discussions with ITER management and staff were positive. It was noted the the draft ITER Long-Term Technology Research and Development Plan contains recommendations for major program effort in materials R D and includes recommendations for coordination among the existing programs of the parties to meet those materials R D needs. ITER management discussions were in the context that decisions on specific activities for the ITER engineering design activity (EDA) must await formal action by the parties on the ITER EDA.

Physicists in HEP have been forced to organize large scientific projects without a well defined organizational or sociological model to guide them. In the absence of such models, what structures do experimentalists use to develop social structures in HEP In this paper, I claim that physicists organize around what they know best, the physics problems they study and the detectors and devices they study them with. After describing the advent of management'' in HEP, I use a case study of 4 Fermilab experiments as the base upon which to propose a physics and detector driven model of social structure for experiments. In addition, I show how this model can be extended to describe strings'' of experiments, where continuities of physics interests, spectrometer design, and a core group of physicists become a definable sociological unit that can exist for over 15 years. A dominate theme that emerges from my analysis is the conscious attempt on the part of experimenters to remove the uncertainties that are part of the practice of HEP.

This report includes: MgCl{sub 2} purification and molten salt preparation facilities have been completed at both the University of Tennessee, Knoxville, and Oak Ridge National Laboratory. The purification of MgCl{sub 2} is being studied. Initial Raman spectral results have been obtained at both facilities. Two analytical spectral techniques involving near-infrared (NIR) and IR reflectance spectral measurements show promise for identifying and quantifying OH species in solid salts of interest. A sealed IR reflectance cell has been developed for use in the project. An electrochemical cell for use in voltammetric studies concerned with the project has been designed and fabricated. 5 refs., 2 figs.

Soudan 2 is an 1100-ton tracking calorimeter which is being built 713 m underground to search for nucleon decay and to study neutrino and cosmic-ray physics. The detector is assembled from 256 identical 4.3-ton calorimeter modules. Each module consists of finely segmented iron and drift tubes, and records three space coordinates and dE/dx for every tube crossing. It is surrounded on all sides by a 1700 m{sup 2} active shield of proportional tubes. The first atmospheric neutrino interactions and a magnetic monopole search are described. Prospects for cosmic ray studies are summarized.

We have investigated the possibility of focusing x-ray lasers with the use of multilayered mirrors or zone plates. The results indicate that x-ray intensities as high as 10{sup 14} W/cm{sup 2} can be achieved by focusing saturated Ne-like x-ray lasers. These intensities should be adequate for studying nonlinear optical phenomena. 9 refs., 2 figs.

An analytical technique has been developed that allows laser-based flow cytometric measurement of the frequency of red blood cells that have lost allele-specific expression of a cell surface antigen due to genetic toxicity in bone marrow precursor cells. Previous studies demonstrated a correlation of such effects with the exposure of each individual to mutagenic phenomena, such as ionizing radiation, and the effects can persist for the lifetime of each individual. During the emergency response to the nuclear power plant accident at Chernobyl, Ukraine, USSR, a number of people were exposed to whole body doses of ionizing radiation. Some of these individuals were tested with this laser-based assay and found to express a dose-dependent increase in the frequency of variant red blood cells that appears to be a persistent biological effect. All data indicate that this assay might well be used as a biodosimeter to estimate radiation dose and also as an element to be used for estimating the risk of each individual to develop cancer due to radiation exposure. 17 refs., 5 figs.

The Fifth International Conference on the Physics of Highly Charged Ions drew more than 200 participants, providing an excellent overview of this growing field. Important technical developments and experimental results in electron-ion collisions were reported. The merging of fast ion beams from accelerators or storage rings with advanced high-intensity electron-beam targets has yielded data of unprecedented quality on radiative and dielectronic recombination, providing stringent tests of theory. Long-awaited technical innovations in electron-impact excitation measurements were also reported. The level of activity in multicharged ion-surface interactions has increased. More sophisticated experimental studies of the neutralization process have shown the inadequacy of previously accepted mechanisms, and theoretical activity in this area is just being initiated. The IAEA meetings addressed atomic and molecular data needs for fusion research, with ITER providing a key focus. Such data are especially critical to modeling and diagnostics of the edge plasma. The ALADDIN data base system has been universally accepted and has streamlined the exchange of numerical data among data centers and the fusion community. The IAEA continues to play a pivotal role in the identification of data needs, and in the coordination of data compilation and research activities for fusion applications.

Recent developments in the application of damped time advance methods to plasma simulations include the synthesis of implicit and explicit adjustably damped'' second order accurate methods for particle motion and electromagnetic field propagation. This paper discusses this method.

We have modified the B2 edge-plasma code to include the effects of classical fluid drifts across the magnetic field lines and plasma currents. This report presents preliminary results of these effects for the CIT parameter regime. The basic plasma model described by Braams involves solving the continuity equation, the parallel momentum balance equation, and separate energy balance equations for the ions and the electrons. If multiple ion species are present, they are all assumed to have a common temperature, but their densities and parallel velocities are solved for using additional continuity and parallel momentum balance equations for each species. Momentum and heat transport parallel to the magnetic field, B, are given by the classical collisional theory. On the other hand, transport perpendicular to B is represented by anomalous diffusion coefficients which are adjusted to agree with experimental measurements. These transport coefficients are generally taken to be constant in radius and poloidal angle, although this is not necessary. The goal of our work has been to include both the classical cross-field drift terms and the effects of parallel currents in the equations used in the B2 code. The motivation for including the cross-field terms comes from simple model calculations which indicate …

One of the goals of biomedical research is the development of imaging techniques capable of producing high resolution ({approximately}300{Angstrom}) three dimensional images of structures within live cells. Recent developments in zone plate lenses at LBL and in x-ray lasers at LLNL indicate that flash three dimensional x-ray microscopy of live biological objects can be achieved in the near term. This concept for a microscope utilizes an x-ray laser to backlit immunogold labeled biological objects. These backlit objects are then imaged with low f-number, high resolution zone plate lenses. Backlighting and imaging along several different directions allows a three dimensional image to be obtained using tomographic techniques.

Nitrate and nitrite have been almost completely removed from the synthetic effluent steam with good efficiency by affecting a separation across a pair of ion exchange membranes. In addition to recovering acid and base in this process, the volume of the remaining effluent is reduced considerably by transport of water across the membrane. One of the problems that remains with this process, however, is the stability of the membranes and particularly the stability of the anion exchange membrane. This membrane is exposed to both nitric acid and strongly alkaline solutions in the cell and to date long term stability has been a problem with the membranes tested. It is recommended that further work should evaluate other newly available membranes as well as study the effects of radiation on the performance of the membranes. The direct reduction of nitrate and nitrite has been studied at several different electrode materials and it has been demonstrated that cathode material has a large effect on both the efficiency and the gas product distribution. Highest current efficiencies for the reduction process are seen at those electrode materials that are known to show high hydrogen overpotentials. Flow cell studies have demonstrated that temperature and current density …

Transient radiated fields due to impulsively excited apertures and aperture response due to incident impulsive waves has been the subject of considerable research in acoustics over the last decade. This research is also of importance to wideband radar. Medical ultrasound steered phased arrays use transmitted pulses consisting of from 1 to 3 cycles of a damped sinusoid, which is similar to certain radar systems. As will be shown, planar arrays using ultra-wide band pulses may be formed with very sparsely spaced elements. This makes feasible very high resolution, economical, and relatively simple, steered beam phased arrays. The resolution may be increased simply by moving the array elements further apart. Grating lobes due to aliasing are not formed when the elements are sparsely spaced. In a very sparse wide band array, element spacing effects the form, or signal shape in time, rather than the peak amplitude of the sidelobe structure. The number of elements in the aperture determines the peak sidelobe level which, in theory, may be decreased without limit. 13 refs., 7 figs.

Experiments in high energy physics require high density and high speed mass storage. Mass storage is needed for data logging during the online data acquisition, data retrieval and storage during the event reconstruction and data manipulation during the physics analysis. This paper examines the storage and speed requirements at the first two stages of the experiments and suggests a possible starting point to deal with the problem. 3 refs., 3 figs.