The thermal conductivity and other properties cementitious grouts have been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. In addition to thermal conductivity, the cementitious grouts were also tested for bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the results for selected grout mixes. Relatively high thermal conductivities were obtained and this leads to reduction in predicted bore length and installation costs. Improvements in shrinkage resistance and bonding were achieved.

Demonstration of Argonne National Laboratory's electrometallurgical treatment of spent nuclear fuel is currently being conducted on irradiated, metallic driver fuel and blanket fuel elements from the Experimental Breeder Reactor-II (EBR-II) in Idaho. The residual metallic material from the electrometallurgical treatment process is consolidated into an ingot, the metal waste form (MWF), by employing an induction furnace in a hot cell. Scanning electron microscopy (SEM) and chemical analyses have been performed on irradiated cladding hulls from the driver fuel, and on samples from the alloy ingots. This paper presents the microstructures of the radioactive ingots and compares them with observations on simulated waste forms prepared using non-irradiated material. These simulated waste forms have the baseline composition of stainless steel - 15 wt % zirconium (SS-15Zr). Additions of noble metal elements, which serve as surrogates for fission products, and actinides are made to that baseline composition. The partitioning of noble metal and actinide elements into alloy phases and the role of zirconium for incorporating these elements is discussed in this paper.

Microfluidic devices with microelectrodes have the potential to enable studies of phenomena at size scales where behavior may be dominated by different mechanisms than at macroscales. Through our work developing microfluidic devices for dielectrophoretic separation and sensing of cells and particles, we have fabricated devices from which general or more specialized research devices may be derived. Fluid channels from 80 {micro}m wide X 20 {micro}m deep to 1 mm wide to 200 {micro}m deep have been fabricated in glass, with lithographically patterned electrodes from 10 to 80 {micro}m wide on one or both sides on the channels and over topographies tens of microns in heights. the devices are designed to easily interface to electronic and fluidic interconnect packages that permit reuse of devices, rather than one-time use, crude glue-based methods. Such devices may be useful for many applications of interest to the electrochemical and biological community.

The US Department of Energy (DOE) National Center of Excellence for Metals Recycle has recently been established. The vision of this new program is to develop a DOE culture that promotes pollution prevention by considering the recycle and reuse of metal as the first and primary disposition option and burial as a last option. The Center of Excellence takes the approach that unrestricted release of metal is the first priority because it is the most cost-effective disposition pathway. Where this is not appropriate, restricted release, beneficial reuse, and stockpile of ingots are considered. Current recycling activities include the sale of 40,000 tons of scrap metal from the East Tennessee Technology Park (formerly K-25 Plant) K-770 scrap yard, K-1064 surplus equipment and machinery, 7,000 PCB-contaminated drums, 12,000 tons of metal from the Y-l2 scrap yard, and 1,000 metal pallets. In addition, the Center of Excellence is developing a toolbox for project teams that will contain a number of specific tools to facilitate metals recycle. This Internet-based toolbox will include primers, computer programs, and case studies designed to help sites to perform life cycle analysis, perform ALARA (As Low As is Reasonably Achievable) analysis for radiation exposures, provide pollution prevention information and …

We have studied events with a high-x{sub F} antiproton and two central jets with E{sub T} > 7 GeV in CDF, in p{anti p} collisions at {radical}s = 1800 GeV. We find an excess of events with a rapidity gap at least 3.5 units wide in the proton direction, which we interpret as di-jet production in double pomeron exchange events.

The electrostatic micro-engine is one of the major actuators used in MEMS applications. To ensure this MEMS actuator is operated in a fashion that will produce peak performance and long life, the system dynamics must be fully understood. One of the major trade-offs in the micro-engine design is the use of either pin or flexure joints. This paper will develop the equations of motion for flexure-jointed and pin-jointed surface micromachined microengines. An analytical mechanics approach will be used to derive the equations of motion and the appropriate equations of constraint. The effect of the flexure joints on the drive signals of the micro engine is experimentally shown to be significant during static tests.

The purpose of this paper is to discuss the relative severity of regulatory impacts onto an essentially rigid target to impacts at higher velocities onto real targets. For impacts onto the essentially rigid target all of the kinetic energy of the package is absorbed by deformation of the package. For impacts onto real targets the kinetic energy is absorbed by deformation of the target as well as by deformation of the package. The amount of kinetic energy absorbed by the target does not increase the severity of the impact.

Type B radioactive material packages are required to withstand a hypothetical puncture accident of a free fall from a height of one meter onto a 15 cm diameter mild steel puncture probe. For many packages it is desirable to have this accident event not result in puncture or tearing of the outer shell of the package. The wall thickness necessary to prevent this has historically been determined by test or the use of empirical relations. This technique generally results in overly conservative designs, but the degree of conservatism is uncertain. The use of modem finite element codes to determine package response to puncture accidents can result in designs that are both safe and economical. The work reported in this paper is aimed at developing a method to analytically determine the wall thickness required to prevent puncture. For designers and regulators to have confidence in this analytical method, however, it must be benchmarked against test results. A series of tests has been conducted with differing shell thicknesses, shell materials of mild steel and stainless steel, and shell backing materials of lead, foam, and air. The results of these tests have been compared with pre-test analytical predictions of the response obtained from …

Crystalline silicotitanate (CST) is a highly specific ion exchange material for cesium. In particular, CST has been successfully demonstrated with both simulants and actual supernates from Savannah River and Hanford tank wastes. As a disposal option, vitrification of the cesium-loaded CST coupled with High-Level Waste (HLW) has been proposed. However, the CST sorbent contains significant quantities of titanium which historically have been difficult to incorporate into the glass structure. Therefore, nonradioactive tests using CST coupled with simulated HLW were performed to develop a glass formulation that would be both processable and durable. The results of the simulated crucible melts were verified using radioactive waste and cesium-loaded CST. This paper will detail the results of the formulation efforts.

Generalized geologic province information and data on house construction were used to predict indoor radon concentrations in New Hampshire (NH). A mixed-effects regression model was used to predict the geometric mean (GM) short-term radon concentrations in 259 NH towns. Bayesian methods were used to avoid over-fitting and to minimize the effects of small sample variation within towns. Data from a random survey of short-term radon measurements, individual residence building characteristics, along with geologic unit information, and average surface radium concentration by town, were variables used in the model. Predicted town GM short-term indoor radon concentrations for detached houses with usable basements range from 34 Bq/m{sup 3} (1 pCi/l) to 558 Bq/m{sup 3} (15 pCi/l), with uncertainties of about 30%. A geologic province consisting of glacial deposits and marine sediments, was associated with significantly elevated radon levels, after adjustment for radium concentration, and building type. Validation and interpretation of results are discussed.

In this work the authors report results of narrowband amplifiers designed for milliwatt and submilliwatt power consumption using JFET and pseudomorphic high electron mobility transistors (PHEMT) GaAs-based technologies. Enhancement-mode JFETs were used to design both a hybrid amplifier with off-chip matching as well as a monolithic microwave integrated circuit (MMIC) with on-chip matching. The hybrid amplifier achieved 8--10 dB of gain at 2.4 GHz and 1 mW. The MMIC achieved 10 dB of gain at 2.4 GHz and 2 mW. Submilliwatt circuits were also explored by using 0.25 {micro}m PHEMTs. 25 {micro}W power levels were achieved with 5 dB of gain for a 215 MHz hybrid amplifier. These results significantly reduce power consumption levels achievable with the JFETs or prior MESFET, heterostructure field effect transistor (HFET), or Si bipolar results from other laboratories.

The author argues that the d{sub x{sup 2}{minus}y{sup 2}}-wave superconductor is marginally stable in the presence of external perturbations. Subjected to the external perturbations by magnetic impurities, it develops a secondary component of the gap, complex d{sub xy}, to maximize the coupling to impurities and lower the total energy. The secondary d{sub xy} component exists at high temperatures and produces the full gap {approximately} 20K in the single particle spectrum around each impurity, apart from impurity induced broadening. At low temperatures the phase ordering transition into global d{sub x{sup 2}{minus}y{sup 2}} + id{sub xy} state occurs.

Small organic scintillators that exhibit pulse shape differences (PSD) in response to charged particles have been investigated as possible neutron detectors in the energy range from 1 to 200 MeV. Neutrons in this energy range can induce reactions such as (n,p) and (n,alpha) in these scintillators, and the cross sections for these reactions vary with energy. Pulse-height and PSD distributions were measured as a function of neutron energy for small crystals of NaI(Tl) and CsI(Tl) at the LANSCE-WNR pulsed spallation neutron source. PSD information indicating the relative numbers of protons and alphas produced can give information about the neutron spectrum in fast-neutron radiation fields such as those encountered in space exploration.

Pellet injection has been used on the DIII-D tokamak to study density limits and particle transport in H-mode and inner wall limited L-mode plasmas. These experiments have provided a variety of conditions in which to examine the fueling efficiency of pellets injected into DIII-D plasmas. The fueling efficiency defined as the total increase in number of plasma electrons divided by the number of pellet fuel atoms, is determined by measurements of density profiles before and just after pellet injection. The authors have found that there is a decrease in the pellet fueling efficiency with increased neutral beam injection power. The pellet penetration depth also decreases with increased neutral beam injection power so that, in general, fueling efficiency increases with penetration depth. The fueling efficiency is generally 25% lower in ELMing H-mode discharges than in L-mode due to an expulsion of particles with a pellet triggered ELM. A comparison with fueling efficiency data from other tokamaks shows similar behavior.

In this study we first discuss a pulsed EPR experiment designed to establish the mechanism of coherence generation [1]. The pulse sequence employed, flash-t-({pi}/2){sub x}-{tau}, consists of a short laser pulse at time zero, followed by a variable period t. At the end of this period a non-ideal ({pi}/2) microwave pulse is applied. The resulting free-induction decay at fixed detection time {tau} is then monitored as a function of successively incremented values of t. For P{sub 700}{sup +} A{sub 1}{sup {minus}} in deuterated and {sup 15}N-substituted PSI preparations, the transverse magnetization shows an oscillatory dependence on the delay between the laser and the microwave pulse [1]. Apparently, there are fast initial oscillations which disappear 250 ns after the laser pulse. In addition, slow persisting oscillations with frequencies of a few MHz can be observed. Basically, these slow oscillations represent nuclear coherences initiated by the laser pulse [1].

Using precisely controlled laboratory conditions we have begun to establish a spectral catalogue of the intermediate ionization states of iron, Fe IX - Fe XXIV, in the extreme ultraviolet. The measurements are being performed in support of the development of reliable modeling codes for the analysis of data from the Extreme Ultraviolet Explorer and future space astrophysics missions sensitive to extreme ultraviolet radiation. They aim to resolve the controversies surrounding the short-wavelength spectra of stellar coronae. Preliminary measurements showing the wealth of iron lines in the 50-120 {Angstrom} region are presented.

Argonne National Laboratory is demonstrating the application of electrometallurgical treatment processes to Experimental Breeder Reactor-II spent nuclear fuel. Begun in June 1996, 100 driver fuel assemblies and 25 blanket fuel assemblies will be conditioned during this demonstration project. In order to validate the technical and economic viability of the technology, the Department of Energy has established four success criteria with specific supporting goals. The results from both laboratory-scale and engineering-scale testing are being used to evaluate the processes, products and equipment against the target goals. The interim results have provided confidence that the integrated electrometallurgical processes will prove to be a viable option for treating problematic spent nuclear fuels for geologic disposal.

The authors describe a class of microscale heaters fabricated with CMOS processes on silicon wafers. These heaters were designed to produce localized high temperatures above 400 C for test and sensor applications. The temperature levels produced for various input powers and the thermal profiles surrounding the heater for packaged and wafer-level heater structures were studied to guide the placement of microelectronics integrated with the heater structures on the same die. To show the performance of the design, they present resistance sensor measurements, IR temperature profiles, and results from a 3D thermal model of the die. This effort demonstrates that it is possible to successfully operate both a microscale heater and microcircuits on the same die.

The Molten Salt Reactor Experiment Facility (MSRE) operated from 1965 to 1969. The fuel was a molten salt that flowed through the reactor core which consisted of uranium tetrafluoride with molten lithium and beryllium salt used as the coolant. In 1968 the fuel was switched from {sup 235}U to {sup 233}U. The Molten Salt Reactor Experiment was canceled in 1969 at which time approximately 4800 kg of salt was transferred to the fuel drain tanks. There was about 36.3 kg of uranium, 675 grams of plutonium and various fission products present in the fuel salt. The salt was allowed to solidify in the fuel drain tanks. The salt was heated on a yearly basis to recombine the fluorine gas with the uranium salt mixture. In March 1994, a gas sample was taken from the off gas system that indicated {sup 233}U had migrated from the fuel drain tank system to the off gas system. It was found that approximately 2.6 kg of uranium had migrated to the Auxiliary Charcoal Bed (ACB). The ACB is located in the concrete-lined charcoal bed cell which is below ground level located outside the MSRE building. Therefore, there was a concern for the potential of …

The purpose of this project is to develop a computer code for joint inversion of seismic and electrical data, to improve underground imaging for site characterization and remediation monitoring. The computer code developed in this project will invert geophysical data to obtain direct estimates of porosity and saturation underground, rather than inverting for seismic velocity and electrical resistivity or other geophysical properties. This is intended to be a significant improvement in the state-of-the-art of underground imaging, since interpretation of data collected at a contaminated site would become much less subjective. Potential users include DOE scientists and engineers responsible for characterizing contaminated sites and monitoring remediation of contaminated sites. In this three-year project, we use a multi-phase approach consisting of theoretical and numerical code development, laboratory investigations, testing on available laboratory and borehole geophysics data sets, and a controlled field experiment, to develop practical tools for joint electrical and seismic data interpretation.

This paper suggests a new technique of growth-oriented KDP crystals in the form of plates. The technique includes: using small oriented seeds spaced between two parallel platforms with a rapid growth of crystals between these two platforms, in a tank containing a KDP solution. As a result, crystals in the form of plates can be obtained. The thickness of the crystal plate depends on the distance between platforms. The horizontal dimensions of the plate depend on the volume of solution and the diameter of the platforms. The orientation of the plates are defined by the orientation of the seed. KDP crystals in the form of plates of two orientations are grown. The peculiarities of morphology and some characteristics of crystals are discussed.

The authors present an inverse method for electron transport which allows one to minimize the value of shot noise for a given value of the conductance by optimizing the spatial structure of a disordered semiconductor region. The method is based on the Green's function approach which is usually applied to the direct transport problem. A specific experimentally realizable example of a two-dimensional disordered semiconductor is presented which demonstrates the method of minimization of shot noise for insulator, metallic, and transitional conductance regions.

Forced-flow, thermal gradient chemical vapor infiltration (FCVI) has been developed for the rapid densification of ceramic matrix composites. For preforms of >3 mm thickness FCVI can produce a near-net-shape part in less than one day as opposed to isothermal, isobaric CVI which requires several weeks to densify such a component. Efforts at ORNL and elsewhere have resulted in capability to produce prototypical thick-walled heat exchanger tubes and turbine disk blanks. This paper will review recent modeling and experimental efforts related to the FCVI of cylindrical forms.

The Tevatron experiments have measured top quark properties in addition to the top quark mass and pair production cross section. These measurements are based on 110 pb{sup -1} of p{anti p} collisions at {radical}s=1.8 TeV recorded by CDF and 125 pb{sup -1} of data recorded by D0 during the years 1992-95. We describe two separate techniques which exploit the top data samples to exclude large branching fractions of the top quark to a charged Higgs boson. we also determine the fraction of longitudinal W bosons produced in top quark decays to be 0.55{+-}0.34, compared to the standard model prediction of 0.71. Other top branching fraction measurements, kinematic studies, and searches for rare decays are summarized.