A letter report issued by the General Accounting Office with an abstract that begins "The U.S. tax system is based on taxpayers voluntarily complying with the tax laws. However, the Internal Revenue Service (IRS) last measured taxpayers' rate of compliance using 1988 tax returns. As time has passed, IRS has become concerned that its ability to understand the effectiveness of its programs and target audits on noncompliant returns has deteriorated, potentially resulting in poorer service to taxpayers, reduced confidence in the fairness of the tax system, and unnecessary audits of compliant taxpayers. IRS is now planning a new compliance study called the National Research Program (NRP). NRP is designed to review 49,000 individual tax returns randomly selected from the population of over 129 million. According to the NRP plan, IRS will review each sampled return to determine whether the taxpayer has complied with statutory income, expense, and tax reporting requirements. Unlike past compliance studies, not all of the reviews will include contacting taxpayers. Based on GAO's assessment of the NRP in light of government guidance on performance measurement and data reliability, research design guidelines, and IRS's goals for the program, NRP's design is likely to yield the sort of detailed …

A letter report issued by the General Accounting Office with an abstract that begins "The Army's purchase card program--the largest within the Defense Department--offers significant benefits, but weak internal controls have left the Army vulnerable to fraudulent, improper, and abusive purchases. The Army has yet to issue servicewide regulations or operating procedures, instead relying on ad hoc memoranda and other informal guidance. The Army also does a poor job of overseeing the purchase card program. The Army lacks the infrastructure--guidance and human capital--needed for effective program oversight. GAO identified several improper transactions involving clothing, food, and other items. GAO also identified improper purchases in which cardholders made a large number of purchases of similar items to circumvent the mandated limit of $2,500 for a single purchase."

Recent advances in solid-state modulators now permit the design of a new class of high current accelerators. These new accelerators will be able to operate in burst mode at frequencies of several MHz with unprecedented flexibility and precision in pulse format. These new modulators can drive accelerators to high average powers that far exceed those of any other technology and can be used to enable precision beam manipulations. New insulator technology combined with novel pulse forming lines and switching may enable the construction of a new type of high gradient, high current accelerator. Recent developments in these areas will be reviewed.

Conductive n-type diamond synthesis was achieved.

The Access Grid is a group-to-group collaborative system developed at Argonne National Laboratory. The system is designed to support high-fidelity, high-bandwidth interactions. This document specifies the minimum requirements that need to be fulfilled for a space to be considered an Access Grid Node.

We consider the case of several scalar fields, charged under a number of U(1) factors, acquiring vacuum expectation values due to anomalous U(1). We demonstrate how to make redefinitions at the superfield level in order to account for tree-level exchange of vector supermultiplets in the effective supergravity theory of the light fields in the supersymmetric vacuum phase. Our approach builds up on previous results that we obtained in a more elementary case. We find that the modular weights of light fields are typically shifted from their original values, allowing an interpretation in terms of the preservation of modular invariance in the effective theory. We address various subtleties in defining unitary gauge that are associated with the noncanonical Kahler potential of modular invariant supergravity, the vacuum degeneracy, and the role of the dilaton field. We discuss the effective superpotential for the light fields and note how proton decay operators may be obtained when the heavy fields are integrated out of the theory at the tree-level. We also address how our formalism may be extended to describe the generalized Green-Schwarz mechanism for multiple anomalous U(1)'s that occur in four-dimensional Type I and Type IIB string constructions.

The possibility to use various target materials are studied for a 2 MW neutrino superbeam facility that can be built at Fermilab utilizing the Main Injector and a Proton Driver. A simple target solution found is a thick graphite rod taking a broad proton beam.

The properties of both carbon and gold substrates are easily affected by the judicious choice of a surface modification protocol. Several such processes for altering surface composition have been published in literature. The research presented in this thesis primarily focuses on the development of on-column methods to modify carbon stationary phases used in electrochemically modulated liquid chromatography (EMLC). To this end, both porous graphitic carbon (PGC) and glassy carbon (GC) particles have been modified on-column by the electroreduction of arenediazonium salts and the oxidation of arylacetate anions (the Kolbe reaction). Once modified, the carbon stationary phases show enhanced chromatographic performance both in conventional liquid chromatographic columns and EMLC columns. Additionally, one may also exploit the creation of aryl films to by electroreduction of arenediazonium salts in the creation of nanostructured materials. The formation of mercaptobenzene film on the surface of a GC electrode provides a linking platform for the chemisorption of gold nanoparticles. After deposition of nanoparticles, the surface chemistry of the gold can be further altered by self-assembled monolayer (SAM) formation via the chemisorption of a second thiol species. Finally, the properties of gold films can be altered such that they display carbon-like behavior through the formation of benzenehexathiol …

There are four important factors which influence the magnitude of the magnetic heat capacity near the magnetic ordering transition temperature. These include the theoretical magnetic entropy, the deGennes factor, crystalline electric field, and the RKKY (Ruderman-Kittel-Kasuya-Yosida) interaction. The lattice contribution to the heat capacity also needs to be considered since it is the sum of the lattice and magnetic contributions which give rise to the heat capacity maxima. The lattice heat capacity depends on the chemical composition, crystal structure and temperature. As a result, one can obtain large changes in the heat capacity maxima by alloying. Several ternary intermetallic systems have been examined in light of these criteria. A number of deviations from the expected behaviors have been found and are discussed.

In this work, we determined how a decanter for the aqueous effluents would work for solvent extraction operations using a centrifugal contactor. Solvent entrainment was measured in the raffinate and strip aqueous effluents in the caustic-side solvent extraction (CSSX) process. Values were obtained for both the solvent concentration and its droplet size distribution. The mixing intensity of the two phases in the mixing zone of the contactor was used to simulate the performance of lab-scale, pilot-plant, and plant-scale contactors. The droplet size distributions were used to estimate the amount of solvent that would be recovered using a decanter tank. It was concluded that the performance of decanter tanks will not be as effective in solvent recovery in the CSSX plan as that of other equipment, such as centrifuges and coalescers. Future testing is recommended to verify the performance of this alternative equipment.

In the first three years of the Fee Tool Project, an immense amount of data on the Delaware Basin has been accumulated. Data on geology, structure, production, regional information such as gravity as well as local data, such as well logs. This data, organized and cataloged into several online databases, is available for the Expert System and users as needed and as appropriate in analyzing production potential.

With the recent discovery of the giant magnetocaloric effect and the beginning of extensive research on the properties of Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, a necessity has developed for a better understanding of the microstructure and crystal structure of this family of rare earth compounds with startling phenomenological properties. The aim of this research is to characterize the microstructure of the Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, with X {approx_equal} 2 and its phase change by using both transmission and electron microscopes. A brief history of past work on Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} is necessary to understand this research in its proper context.

In a cellular array, a range of primary spacing is found to be stable under given growth conditions. Since a strong coupling of solute field exists between the neighboring cells, primary spacing variation should also influence other microstructure features such as cell shape and cell length. The existence of multiple solutions is examined in this study both theoretically as well as experimentally. A theoretical model is developed that identifies and relates four important microstructural lengths, which are found to be primary spacing, tip radius, cell width and cell length. This general microstructural relationship is shown to be valid for different cells in an array as well as for other cellular patterns obtained under different growth conditions. The unique feature of the model is that the microstructure correlation does not depend on composition or growth conditions since these variables scale microstructural lengths to satisfy the relationship obtained in this study. Detailed directional solidification experimental studies have been carried out in the succinonitrile-salol system to characterize and measure these four length scales. Besides the validation of the model, experimental results showed additional scaling laws to be present. In the regime where only a cellular structure is formed, the shape of the cell, …

The presence of actinides in spent fuel destined for a geologic repository such as the proposed Yucca Mountain Repository causes a substantial long term heat load, causes the radiotoxicity of the waste to remain high for tens of thousands of years, and contributes significantly to the long-term dose rate once waste packages begin to fail. Examples, mostly based on the current design of the proposed repository, are considered to illustrate the potential impact of actinide removal on each of these factors. The analyses show that removal of 90 to 99% of the actinides may significantly increase in the capacity of a repository. In addition, the radiotoxicity of the waste may be reduced to a value less than that of the uranium ore from which the fuel was manufactured within the 10,000-year regulatory period. For example, removal of 99.9% of the actinides reduces the radiotoxicity to a level less than that of the original ore in less than 400 years. Finally, removal of 99% of the actinides could reduce the peak long-term dose rate, estimated to occur after about 270,000 years, by as much as a factor of 60.

Capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) are widely used analytical separation techniques with many applications in chemical, biochemical, and biomedical sciences. Conventional analyte identification in these techniques is based on retention/migration times of standards; requiring a high degree of reproducibility, availability of reliable standards, and absence of coelution. From this, several new information-rich detection methods (also known as hyphenated techniques) are being explored that would be capable of providing unambiguous on-line identification of separating analytes in CE and HPLC. As further discussed, a number of such on-line detection methods have shown considerable success, including Raman, nuclear magnetic resonance (NMR), mass spectrometry (MS), and fluorescence line-narrowing spectroscopy (FLNS). In this thesis, the feasibility and potential of combining the highly sensitive and selective laser-based detection method of FLNS with analytical separation techniques are discussed and presented. A summary of previously demonstrated FLNS detection interfaced with chromatography and electrophoresis is given, and recent results from on-line FLNS detection in CE (CE-FLNS), and the new combination of HPLC-FLNS, are shown.

The spherical torus (ST) concept underlies several contemporary plasma physics experiments, in which relatively low magnetic fields, high plasma edge q, and low aspect ratio combine for potentially compact, high beta and high performance fusion reactors. An important issue for the ST is the calculation of energetic ion confinement, as large Larmor radius makes conventional guiding center codes of limited usefulness and efficient plasma heating by RF and neutral beam ion technology requires minimal fast ion losses. The National Spherical Torus Experiment (NSTX) is a medium-sized, low aspect ratio ST, with R=0.85 m, a=0.67 m, R/a=1.26, Ip*1.4 MA, Bt*0.6 T, 5 MW of neutral beam heating and 6 MW of RF heating. 80 keV neutral beam ions at tangency radii of 0.5, 0.6 and 0.7 m are routinely used to achieve plasma betas above 30%. Transport analyses for experiments on NSTX often exhibit a puzzling ion power balance. It will be necessary to have reliable beam ion calculations to distinguish among the source and loss channels, and to explore the possibilities for new physics phenomena, such as the recently proposed compressional Alfven eigenmode ion heating.

Astrocytes, a subtype of glial cell, have recently been shown to exhibit Ca{sup 2+} elevations in response to neurotransmitters. A Ca{sup 2+} elevation can propagate to adjacent astrocytes as a Ca{sup 2+} wave, which allows an astrocyte to communicate with its neighbors. Additionally, glutamate can be released from astrocytes via a Ca{sup 2+}-dependent mechanism, thus modulating neuronal activity and synaptic transmission. In this dissertation, the author investigated the roles of another endogenous signal, nitric oxide (NO), in astrocyte-neuron signaling. First the author tested if NO is generated during astrocytic Ca{sup 2+} signaling by imaging NO in purified murine cortical astrocyte cultures. Physiological concentrations of a natural messenger, ATP, caused a Ca{sup 2+}-dependent NO production. To test the roles of NO in astrocytic Ca{sup 2+} signaling, the author applied NO to astrocyte cultures via addition of a NO donor, S-nitrosol-N-acetylpenicillamine (SNAP). NO induced an influx of external Ca{sup 2+}, possibly through store-operated Ca{sup 2+} channels. The NO-induced Ca{sup 2+} signaling is cGMP-independent since 8-Br-cGMP, an agonistic analog of cGMP, did not induce a detectable Ca{sup 2+} change. The consequence of this NO-induced Ca{sup 2+} influx was assessed by simultaneously monitoring of cytosolic and internal store Ca{sup 2+} using fluorescent Ca{sup 2+} …

Studies of random laser systems are a new direction with promising potential applications and theoretical interest. The research is based on the theories of localization and laser physics. So far, the research shows that there are random lasing modes inside the systems which is quite different from the common laser systems. From the properties of the random lasing modes, they can understand the phenomena observed in the experiments, such as multi-peak and anisotropic spectrum, lasing mode number saturation, mode competition and dynamic processes, etc. To summarize, this dissertation has contributed the following in the study of random laser systems: (1) by comparing the Lamb theory with the Letokhov theory, the general formulas of the threshold length or gain of random laser systems were obtained; (2) they pointed out the vital weakness of previous time-independent methods in random laser research; (3) a new model which includes the FDTD method and the semi-classical laser theory. The solutions of this model provided an explanation of the experimental results of multi-peak and anisotropic emission spectra, predicted the saturation of lasing modes number and the length of localized lasing modes; (4) theoretical (Lamb theory) and numerical (FDTD and transfer-matrix calculation) studies of the origin of …

The effects on phase separation and emulsion formation of variables present in the caustic washing of solvent in the caustic-side solvent extraction process have been investigated. The evaluation program was performed in two experiments; results of the first experiment were used to determine conditions for the second test. In the first experiment, the effects of solvent degradation product concentrations (4-sec-butylphenol and dioctylamine), wash solution NaOH concentration, and solvent-to-wash solution volume ratio (O:A) on phase separation were examined. Phase separation performance was quantified in terms of the dimensionless dispersion number, which is also a variable used in the prediction of centrifugal contactor performance by computational means. In the second experiment, phase separation performance in a 5-cm centrifugal contactor was investigated as a function of contactor speed, aqueous-phase NaOH concentration, and solvent-to-wash volume ratio. Separation performance was quantified in terms of the maximum throughput that could be achieved without resulting in >1% contamination of either effluent phase with the opposing phase. Results of the first experiment indicated that none of the variables considered affected phase separation performance at a 95% significance level and that dioctylamine concentration was the only single factor that affected phase separation at a 90% significance level. The results …

The structural transformations that occur in diamondlike carbon coatings with increasing hydrogen content have been investigated by Raman spectroscopy, transmission electron microscopy, electron diffraction, and electron-energy-loss spectroscopy. Friction tests were performed with uncoated steel balls against coated substrates at contact stresses of 1 GPa in ambient air (relative humidity = 30 - 40%), dry air (relative humidity < 1%), and dry nitrogen (< 1%). The lowest friction coefficient (f < 0.02) was obtained for the most hydrogenated sample in dry nitrogen, where the formation of a third-body layer was observed on the steel surface. Raman spectra obtained from the counterfaces after sliding in humid and dry air revealed a remarkable increase and narrowing of the ''D'' and ''G'' peaks with decreasing humidity. Analysis of peak positions and I(D)/I(G) ratios pointed to an increasing order and an enlargement of the sp{sup 2} clusters under friction. The shape and position of the carbon K-edge spectra for the transfer layer are affected the same way, although evidence of extended graphite layer formation was not observed. Development of these differing trends was correlated with the hydrogen-to-carbon ratio of the gas precursor used during the synthesis and with the type of surrounding atmosphere.

This document describes the operation and use of the Portable Nondestructive Assay (NDA) II equipment for use in the determination of {sup 235}U enrichment of uranium of various chemical forms and contained in different vessels. The Portable NDA II is the next generation NDA equipment assembled by Lawrence Livermore National Laboratory (LLNL) for the Department of Energy's Highly Enriched Uranium-Transparency Implementation Program (HEU-TIP). Presented in this document is an overview of the enrichment measurement methodology, instructions for the assembly and disassembly of the equipment, description of and user's guide for the UMeter enrichment meter software and a section on system troubleshooting. Also included herewith are facility-specific information and parameters for each of the HEU-processing sites subject to the HEU Transparency Implementation Program.

Five different experiments on thermal heating of explosive materials have been performed. Three experiments thermally exploded PBX 9501 (HMX/Estane/BDNPA-F; 9512.512.5 wt %) donor charges while two others thermally exploded LX-04 (HMX/Viton A; 85/15 wt %). These donor charges were encased in 304 stainless steel. The transmitted two-dimensional pressure waves were measured by gauges in acceptor cylinders of Teflon, PBX 9501, or LX-04 that were in contact with the donors' steel case. A fifth experiment measured the pressure in an acceptor charge of PBX 9501 that had a 100 mm stand-off from the top of the steel case of the thermally cooked off PBX 9501 donor charge. Reactive flow hydrodynamic modeling using a rapid deflagration velocity of approximately 500 m/s was able to reproduce the pressure gauge records for both the in contact and stand off experiments that used PBX 9501 donors and acceptors.

The amplifier top plates are monolithic, cast aluminum structures from which the amplifier frame assembly units (FAUs), and the line-replaceable flash lamp units (LRUs) inside them, are hung on the support rails in the laser bays. When fully assembled, each plate must support a static weight of 10,600 or 16,000 pounds, depending upon whether two or three loaded FAUs are attached. The top plates are fabricated from ''ALCA Plus{trademark}'', a zinc-containing aluminum casting alloy similar in composition to some standard alloys in the 7000-series. For electrical reasons, all of the plate with the exception of the support ''ears'', is encased in epoxy as shown in Figure 1. The nominal chemistry of the aluminum alloy is summarized in Table 1 and the nominal mechanical characteristics are summarized in Table 2. For comparison, wrought alloys of similar composition in the 7000-series have ultimate strengths of approximately 33-76 ksi and elongations of 11-17%, depending upon the temper.

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