Relationships between intrinsic mechanical hardness and atomic-scale properties are reviewed, Hardness scales closely and linearly with shear modulus for a given class of material (covalent, ionic or metallic). A two-parameter fit and a Peierls-stress model produce a more universal scaling relationship, but no model can explain differences in hardness between the transition metal carbides and nitrides. Calculations of ''ideal strength'' (defined by the limit of elastic stability of a perfect crystal) are proposed. The ideal shear strengths of fcc aluminum and copper are calculated using ab initio techniques and allowing for structural relaxation of all five strain components other than the imposed strain. The strengths of Al and Cu are similar (8-9% of the shear modulus), but the geometry of the relaxations in Al and Cu is very different. The relaxations are consistent with experimentally measured third-order elastic constants. The general thermodynamic conditions of elastic stability that set the upper limits of mechanical strength are derived. The conditions of stability are shown for cubic (hydrostatic), tetragonal (tensile) and monoclinic (shear) distortions of a cubic crystal. The implications of this stability analysis to first-principles calculations of ideal strength are discussed, and a method to detect instabilities orthogonal to the direction of …

The author performs image reconstruction for a novel Positron Emission Tomography camera that is optimized for breast cancer imaging. This work addresses for the first time, the problem of fully-3D, tomographic reconstruction using a septa-less, stationary, (i.e. no rotation or linear motion), and rectangular camera whose Field of View (FOV) encompasses the entire volume enclosed by detector modules capable of measuring Depth of Interaction (DOI) information. The camera is rectangular in shape in order to accommodate breasts of varying sizes while allowing for soft compression of the breast during the scan. This non-standard geometry of the camera exacerbates two problems: (a) radial elongation due to crystal penetration and (b) reconstructing images from irregularly sampled data. Packing considerations also give rise to regions in projection space that are not sampled which lead to missing information. The author presents new Fourier Methods based image reconstruction algorithms that incorporate DOI information and accommodate the irregular sampling of the camera in a consistent manner by defining lines of responses (LORs) between the measured interaction points instead of rebinning the events into predefined crystal face LORs which is the only other method to handle DOI information proposed thus far. The new procedures maximize the use …

An implicit version of the Smooth Particle Hydrodynamic (SPH) code SPHINX has been written and is working. In conjunction with the SPHINX code the new implicit code models fluids and solids under a wide range of conditions. SPH codes are Lagrangian, meshless and use particles to model the fluids and solids. The implicit code makes use of the Krylov iterative techniques for solving large linear-systems and a Newton-Raphson method for non-linear corrections. It uses numerical derivatives to construct the Jacobian matrix. It uses sparse techniques to save on memory storage and to reduce the amount of computation. It is believed that this is the first implicit SPH code to use Newton-Krylov techniques, and is also the first implicit SPH code to model solids. A description of SPH and the techniques used in the implicit code are presented. Then, the results of a number of tests cases are discussed, which include a shock tube problem, a Rayleigh-Taylor problem, a breaking dam problem, and a single jet of gas problem. The results are shown to be in very good agreement with analytic solutions, experimental results, and the explicit SPHINX code. In the case of the single jet of gas case it has …

January Progress--A kick-off meeting was held in San Diego with Alturdyne on January 21st. The proposed hybrid gas/electric chiller/cogenerator design concept was discussed in detail. The requirements and functionality of the key component, a variable speed, constant frequency motor/generator was presented. Variations of the proposed design were also discussed based on their technical feasibility, cost and market potential. The discussion is documented in a Trip Report. February Progress--After significant GRI/Alturdyne discussion regarding alternative product design concepts, the team made a decision to continue with the proposed product design, a hybrid chiller capable of also providing emergency power. The primary benefits are: (a) the flexibility and operating cost savings associated with the product's dual fuel capability and (b) the emergency power feature. A variable speed, constant frequency motor/generator would significantly increase the cost of the product while providing marginal benefit. (The variable speed, constant frequency motor generator is estimated to cost $25,000 versus $4,000 for a constant speed version). In addition, the interconnection requirements to the electric grid would significantly limit market penetration of the product. We will proceed with a motor/generator design capable of serving as the electric prime mover for the compressor as well as the generator for emergency …

We have completed 18 months of this project and are reporting progress we have made in the areas of fracture and reservoir modeling. Task 1a: Construct Model of Outcrop Stratigraphic Framework has been completed. Task 1b: Construct Model of Fine-Scale Petrophysical Heterogeneity has been completed. Task 1c: Construct Model of Fracture Porosity and Permeability the object of this task is to characterize fracture porosity and distribution in the Wasson Clear Fork reservoir and to determine the effects of fractures on well performance. The approach is to measure fracture attributes in an analog outcrop, to develop models of fracture spacing and aperture, and to apply this information to the South Wasson Clear Fork reservoir. A data set has been collected from outcrops of the Clear Fork Formation, Apache Canyon, Sierra Diablo Mountains, West Texas, and a summary of the results is presented.

Computational models of particle dynamics often exchange solution data with discretized continuum-fields using interpolation functions. These particle methods require a series expansion of the interpolation function for two purposes: numerical analysis used to establish the model's consistency and accuracy, and logical-coordinate evaluation used to locate particles within a grid. This report presents discrete-expansions for a linear interpolation function commonly used within triangular cell geometries. Discrete-expansions, unlike a Taylor's series, account for interpolation discontinuities across cell boundaries and, therefore, are valid throughout a discretized domain. Verification of linear discrete-expansions is demonstrated on a simple test problem.

Other written product issued by the General Accounting Office with an abstract that begins "This journal of the International Organization of Supreme Audit Institution (INTOSAI) includes articles concerning: (1) auditing in the South Pacific; (2) new training infrastructure in the Asian Organization of Supreme Audit Institutions; (3) national responsibilities and international activities of selected Supreme Audit Institutions; (4) the office of the Auditor General of Mexico; (5) reports in print; and (6) activities within INTOSAI."

Other written product issued by the General Accounting Office with an abstract that begins "This French-language edition of the Journal of the International Organization of Supreme Audit Institutions (INTOSAI) includes articles concerning (1) auditing in the South Pacific, (2) new training infrastructure in the Asian Organization of Supreme Audit Institutions, (3) national responsibilities and and international activities of selected Supreme Audit Institutions, (4) the office of the Auditor General of Mexico, (5) reports in print, and (6) activities within INTOSAI."

Other written product issued by the General Accounting Office with an abstract that begins "This journal of the International Organization of Supreme Audit Institution (INTOSAI) includes articles concerning: (1) auditing in the South Pacific; (2) new training infrastructure in the Asian Organization of Supreme Audit Institutions; (3) national responsibilities and international activities of selected Supreme Audit Institutions; (4) the office of the Auditor General of Mexico; (5) reports in print; and (6) activities within INTOSAI."

Other written product issued by the General Accounting Office with an abstract that begins "This Spanish-language edition of the Journal of the International Organization of Supreme Audit Institutions (INTOSAI) includes articles regarding (1) auditing in the South Pacific, (2) new training infrastructure in the Asian Organization of Supreme Audit institutions, (3) national responsibilities and international activities of selected Supreme Audit Institutions, (4) the office of the Auditor General of Mexico, (5) reports in print, and (6) activities within INTOSAI."

Other written product issued by the General Accounting Office with an abstract that begins "GAO provided information on the Joint Financial Management Improvement Program's current financial management initiatives, activities, and practices."

After the Iraq war, the International Atomic Energy Agency (IAEA) 93+2 Program was developed to strengthen and improve the cost-effectiveness of the existing safeguards system. In particular, the Program aims to enhance the IAEA ability to detect undeclared nuclear activities and materials. The IAEA 93+2 Program includes: (1) Increased access to information and its effective use; (2) Increased physical access; (3) Optimum use of the existing system. The measures considered are divided in two parts: measures in Part 1 are those, which may be implemented within the existing IAEA authority; Part 2 measures require complementary legal authority, in the form of an additional Protocol, INFCIRC/540. A description of the status of its implementation can be found in ``Implementation of the Additional Protocol'' (Cooley, 1999). In particular, increased physical access includes access beyond locations requiring additional authorities derived from the INFCIRC/540 and no-notice randomized inspections. No-notice randomized inspections could enhance the inspection effectiveness and efficiency by increasing the coverage of the material involved, providing better confirmation of the operational status of the facilities and higher degree of confidence that no undeclared activities or materials existed at the facilities--including the detection of possible measures to conceal diversions.

Seven improved decontamination and decommissioning (D&D) technologies were successfully deployed at the Idaho National Engineering and Environmental Laboratory (INEEL) during the Accelerated Site Technology Deployment (ASTD) Integrated Decontamination and Decommissioning (ID&D) project. The use of these improved technologies saved the INEEL $462K in fiscal year 1999, and is projected to save about $14M over the next ten years. Since deploying new technologies on D&D projects shows great potential for cost-savings, factors that led to successful deployment have been documented. These factors are described here as they apply to the seven deployments at the INEEL to assist with deployments at other DOE sites.

Laser results are summarized for the low-phonon hosts KPb{sub 2}Cl{sub 5} and CaGa{sub 2}S{sub 4}. Radiative quantum efficiencies were determined in KPb{sub 2}Cl{sub 5}:Dy{sup 3+} directly from emission spectra in order to accurately determine its long-wavelength potential. The results indicate that room-temperature laser action should be possible to near 9 {micro}m in this host.

Newsletter of the Texas Agricultural Extension Service discussing plants that are cultivated in the state, news, and other topics related to gardening in Texas.

A study of the drift in Pd/Ni alloy hydrogen sensitive resistor and transistor responses is presented. The sensors were monitored for a period of 6 months in a reducing atmosphere of 0.1% H{sub 2} in N{sub 2} with periodic calibration exposures. A comparison of a resistor film with an adhesion layer showed considerable improvement in diminishing the drift.

The goal of this research program is to develop and deliver a procedure guide of low cost methodologies to analyze and correct problems with stripper wells experiencing abnormal production declines. A study group of wells will provide data to determine the historic frequency of the problem of abnormal production declines in stripper gas wells and the historic frequency of the causes of the production problems. Once the most frequently occurring causes of the production problems are determined, data collection forms and decision trees will be designed to cost-effectively diagnose these problems and suggest corrective action. Finally, economic techniques to solve the most frequently occurring problems will be researched and implemented. These systematic methodologies and techniques will increase the efficiency of problem assessment and implementation of solutions for stripper gas wells. This second quarterly technical report describes the data reduction and methodology to develop data collection forms of pertinent information to assist in analysis of problem wells. The report also describes the procedures to categorize individual well problems. Finally, the report summarizes the frequency of individual well problems.

This document provides information on managing external parasites in livestock and poultry.

The authors analysis of small-scale LWC fluctuations in PVM-100A data from SOCEX-1 supports the still controversial claim that droplet concentration is not everywhere Poissonian. This does not exclude a slow (spectral exponent {beta} = 5/3) low-amplitude component in the variability of droplet number and size distribution. We believe the cause of the excess small-scale LWC variance causing the scale-break at 2--5 m lies in entrainment- and/or-mixing events; such processes maybe related to the intermittency (occasional bursts of variability at the inner-scale) associated with the large-scale multifractality. Comparing exponents obtained for large-scale behavior with those previously obtained from two other field programs, we uncover remarkable similarities between the basic multifractal (i.e., arbitrary-order structure function) properties of LWC in SOCEX, FIRE'87 and ASTEX clouds and those of passively advected scalars in turbulent flows. However, we also find interesting differences between the three kinds of marine cloud cover and with passive scalars but these are in the details of the various multifractal characterizations (inner and outer scales, high-order scaling). To reproduce these statistical behaviors defines a quantitatively-precise challenge for the cloud-modeling community.

This paper will discuss the methods used at a depleted uranium facility to develop a hazard categorization and a limiting condition for operation (LCO) for the inventory based on increased Category 2 threshold quantity values (TV) from DOE Standard 1027-92. A revision to the safety analysis report (SAR) for a Category 3 depleted uranium facility was required to meet current methodologies and isotope content. The previous SAR first approved in 1992, allowed an inventory of depleted uranium that exceeded the Category 2 threshold quantity values in the material storage warehouses using an accident analysis methodology for final hazard categorization. New information regarding the isotopic content of the depleted uranium required an updated hazard categorization evaluation. The DOE Standard 1027-92 requires the evaluation to be based on inventory (Reference 1, 3.1, page 5), therefore, the previous method of performing a hazard consequence and probability analysis could not be used. The standard (1027) requires a facility to be designated as a Category 3 Nuclear facility when the inventory levels in the facility, or facility segments, are greater than Category 3 thresholds and below Category 2 thresholds. A Category 2 Nuclear Facility requires a more in depth hazard and accident analysis. Our categorization …

Monthly report discussing cancer care and research to inform physicians.

An accelerator-based experiment was performed using the CEBAF accelerator of the Thomas Jefferson National Accelerator Facility to investigate a predicted sensitivity of the beam polarization to the vertical betatron orbit in the recirculation arcs. This is the first measurement of any such effect at CEBAF, and provides information about the polarized beam delivery performance of the accelerator. A brief description of the accelerator is given, followed by the experimental methods used and the relevant issues involved in measuring a small ({approximately} 10{sup {minus}2}) change in the beam polarization. Results of measurements of the polarization sensitivity parameters and the machine energy by polarization transport techniques are presented. The parameters were obtained by measurement of the strength of the effect as a function of orbit amplitude and spin orientation, to confirm the predicted coupling between the spin orientation and the quadrupole fields in the beam transport system. This experiment included characterizing the injector spin manipulation system and 5 MeV Mott polarimeter, modeling of the polarization transport of the accelerator, installation of magnets to create a modulated orbit perturbation in a single recirculation arc, and detailed studies of the Hall C Moeller polarimeter.

None

The 1990 Clean Air Act Amendments required the U.S. Environmental Protection Agency (EPA) to determine whether the presence of mercury in the stack emissions from fossil fuel-fired electric utility power plants poses an unacceptable public health risk. EPA's conclusions and recommendations were presented in the ''Mercury Study Report to Congress'' and ''Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units''. The first report addressed both the human health and environmental effects of anthropogenic mercury emissions, while the second addressed the risk to public health posed by the emission of mercury and other hazardous air pollutants from steam electric generating units. Although these reports did not state that mercury controls on coal-fired electric power stations would be required given the current state of the art, they did indicate that the EPA views mercury as a potential threat to human health. Therefore, it was concluded that mercury controls at some point may be necessary. EPA also indicated that additional research/information was necessary before any definitive statement could be made. In an effort to determine the amount and types of mercury being emitted into the atmosphere by coal-fired power plants, EPA in late 1998 issued an information collection request (ICR) …