The effects of certain pulse-shaping networks on the signal-to-noise ratio of a nuclear pulse amplifier were considered. The shaping networks discussed are: equal RC-integrating and RC-differentiating time constant, single- delay-line clipper and RC integrator, and doubledelay-line clipper and RC integrator. The effects of these networks on the signal, when high count rates and overload pulses are present, were also considered. Equations and curves were developed for the energy resolution (signal-tonoise ratio) and resolving time (related to the ability to operate at high counting rates) of the networks. Experimental results are shown for the energy resolution of the types of pulse- shaping networks considered. (auth)

A semiconductor laser has certain properties which makes its use desirable as a continuous monitor of atmospheric pollutants. Its energy output is concentrated in widely separated energy modes of very narrow bandwidths (less than 10/sup -5/ cm/sup -1/) which can be centered on one infrared absorption line of one gas. This makes the laser quite selective. The energy in each mode is typically greater than 200 ..mu.. watts, and, because of the laser's small size, its light energy can be collimated over large distances with minimal optical losses and be easily detected. One can rapidly measure the decrease in transmission of the light due to the absorption of the light by the gas being monitored, and, using certain analytical parameters, which are different for each absorption line, one can determine the concentration of the gas in question immediately. In addition to the line center (nu/sub 0/), these analytical parameters are the intensity (S) and the half width at half maximum (..gamma..). The intensity (S) is dependent only on temperature when expressed in a per concentration basis and ..gamma.. is dependent on pressure. The Lorentzian lineshape equation K(nu) + S/..pi gamma..(((nu - nu/sub 0/)/..gamma..)/sup 2/ + 1)/sup -1/ is the equation …

The simultaneous determination of up to 20 trace elements in various oil matrices by inductively coupled plasma-atomic emission spectrometry is reported. The oil matrices investigated were lubricating oils (for wear metals), fuel oil, centrifuged coal liquefaction product, crude soybean oil, and commercial edible oils. The samples were diluted with appropriate organic solvents and injected into the plasma as an aerosol generated by a pneumatic nebulization technique. Detection limits of the 28 elements studied ranged from 0.0006 to 9 ..mu..g/g with the majority falling in the 0.01 to 0.1 ..mu..g/g range. Analytical calibration curves were linear over at least two orders of magnitude and for some elements this linearity extended over 4.5 orders of magnitude. Relevant data on precision and accuracy are included. Because metals often occur as particles in lubricating oil and coal liquefaction products, the effect of particles on the analytical results was examined. Wear metal particles in used oil did not appear to affect the analytical results. However, incomplete recovery relative to organometallic reference solutions was obtained for iron particles with a nominal mean diameter of 3.0 ..mu..m suspended in oil. It was shown that the following factors contributed to incomplete recovery for the particles: settling of the …

A dibutyl amide resin is used for the separation of uranium(VI), thorium(IV), and zirconium(IV) from each other and several other metal ions. Uranium(VI) and thorium(IV) are determined in the presence of large excesses of foreign metal ions and anions. A practical application of the amide resin is studied by determining uranium in low grade uranium ores. The amide resin is also used for the selective concentration of gold(III) from sea water.

This research is concerned with the solvent extraction into chloroform of the lanthanides, using 2,5-dimethyl-2-hydroxyhexanoic acid (DMHHA). This acid is the first ..cap alpha..-hydroxy aliphatic acid to be studied as an extracting agent for the lanthanides. The chloroform-water DMHHA partition constant was determined to be 1.0 (at 0.1 M ionic strength and 25/sup 0/C). The acid dimerizes in chloroform with a constant of 56. The light lanthanides can be extracted into chloroform by forming complexes with the DMHHA anions. The extracted metal species is highly aggregated. This extraction has a solubility limit which increases with the addition of unionized acid. The resultant extract is also highly aggregated. At unionized acid-to-metal ratios greater than one, extractions first occur followed by the slow precipitation of the lanthanide. At the tracer level, neodymium is extracted primarily as NdA/sub 3/(HA)/sub 5/ and (NdA/sub 3/)/sub 2/(HA)/sub q/. Very small amounts of (NdA/sub 3/)/sub 2/ and other metal aggregates are also present. The heavy lanthanides do not extract from solutions of DMHHA and its potassium salt, but form aqueous emulsions and precipitates. In the presence of the organic soluble tetrabutylammonium ion the heavy lanthanides can be extracted, presumably as ion pairs. The stability constants of the …

None

Lateral changes in geology pose a serious problem in data interpretation for any surface geophysical method. Although many geophysical techniques are designed to probe vertically, the source signal invariably spreads laterally, so any lateral variations in geology will affect the measurements and interpretation. This problem is particularly acute for controlled source electromagnetic soundings because only a few techniques are available to interpret the data if lateral effects are present. In this thesis we examine the effects of geological contacts for the time domain electromagnetic sounding method (TDEM). Using two simple two-dimensional models, the truncated thin-sheet and the quarter-space, we examine the system response for several commonly used TDEM sounding configurations. For each system we determine the sensitivity to the contact, establish how to the contact anomaly may be distinguished from other anomalies and, when feasible, develop methods for interpreting the contact geometry and for stripping the contact anomaly from the observed data. Since no numerical models were available when this work was started, data were collected using scale models with a system designed at the University of California at Berkeley. The models were assembled within a table-top modeling tank from sheets or blocks of metal using air or mercury as …

Energy curves are determined for the lowest singlet and triplet states of the HNO molecule. The geometry is varied in that the hydrogen moves through 13 positions around the NO core to describe the isomerization reaction HNO yields HON. Quantitatively determined are the stable and metastable equilibrium positions in both states, the energy differences between these two equilibrium positions and between the two states, and the barriers with respect to isomerization. The calculations are carried out using a novel configuration interaction approach called the Full Optimized Reaction Space method, which involves multiconfigurational self-consistent field calculations as an integral part. In order to interpret the bonding changes occurring during the reaction, a novel type of orbital is developed and calculated. These are called Directed Localized Reaction Orbitals. With their help it proves possible to give an interpretation of the isomerization in terms of concepts which fit chemical intuition.

A unique phonon progression in the phosphorescence spectrum of pyrene-PMDA (Py-PMDA) in naphthalene-PMDA (N-PMDA) is reported. Calculations of the electron-phonon coupling strength parameter for the ground and excited states indicate strong coupling for the fractional CT contribution of Py-PMDA to the observed phosphorescent state. Model calculations indicate that the observed low frequency phonon mode corresponds to a low energy rotation of the rigid guest complex and not a symmetric donor-acceptor stretch. The unusual reduction of the phonon mode frequency in the excited ground state is explained in terms of a contracted complex that can more easily rotate in a larger cavity. A brief phonon progression is also observed for the mixed crystal A-PMDA in N-PMDA. For both mixed crystals, Py-PMDA in N-PMDA and A-PMDA in N-PMDA, the energy spacing between the zero-phonon vibrational bands in the mixed CT crystal phosphorescence spectrum are very similar to those obtained from the phosphorescence spectrum of the pure donor in a rigid matrix. There is a large blue shift between the origin band of the mixed CT crystal phosphorescence spectrum and the origin band of the pure donor phosphorescence spectrum for the A-PMDA mixed crystal, but not for the Py-PMDA mixed crystal. The structureless …

MINOS, the Main Injector Neutrino Oscillation Search, is a long baseline neutrino oscillation experiment based at Fermilab National Accelerator Laboratory. The experiment uses a neutrino beam, which is measured 1 km downstream from its origin in the Near detector at Fermilab and then 735 km later in the Far detector at the Soudan mine. By comparing these two measurements, MINOS can attain a very high precision for parameters in the atmospheric sector of neutrino oscillations. In addition to precisely determining {Delta}m{sub 23}{sup 2} and {theta}{sub 23} through the disappearance of {nu}{sub {mu}}, MINOS is able to measure {nu}{sub {mu}} {yields} {nu}{sub sterile} by looking for a deficit in the number of neutral current interactions seen in the Far detector. In this thesis, we present the results of a search for sterile neutrinos in MINOS.

The authors present precision measurements of the direct CP violation parameter, Re({epsilon}{prime}/{epsilon}), the kaon parameters, {Delta}m and {tau}{sub S}, and the CPT tests, {phi}{sub {+-}} and {Delta}{phi}, in neutral kaon decays. These results are based on the full dataset collected by the KTeV experiment at Fermi National Accelerator Laboratory during 1996, 1997, and 1999. This dataset contains {approx} 15 million K {yields} {pi}{sup 0}{pi}{sup 0} decays and {approx} 69 million K {yields} {pi}{sup +}{pi}{sup -} decays. They describe significant improvements to the precision of these measurements relative to previous KTeV analyses. They find Re({epsilon}{prime}/{epsilon}) = [19.2 {+-} 1.1(stat) {+-} 1.8(syst)] x 10{sup -4}, {Delta}m = (5265 {+-} 10) x 10{sup 6} hs{sup -1}, and {tau}{sub S} = (89.62 {+-} 0.05) x 10{sup -12} s. They measure {phi}{sub {+-}} = (44.09 {+-} 1.00){sup o} and {Delta}{phi} = (0.29 {+-} 0.31){sup o}; these results are consistent with CPT symmetry.

Rapid solidification of novel mixed rare earth-iron-boron, MRE{sub 2}Fe{sub 14}B (MRE = Nd, Y, Dy; currently), magnet alloys via high pressure gas atomization (HPGA) have produced similar properties and structures as closely related alloys produced by melt spinning (MS) at low wheel speeds. Recent additions of titanium carbide and zirconium to the permanent magnet (PM) alloy design in HPGA powder (using He atomization gas) have made it possible to achieve highly refined microstructures with magnetic properties approaching melt spun particulate at cooling rates of 10{sup 5}-10{sup 6}K/s. By producing HPGA powders with the desirable qualities of melt spun ribbon, the need for crushing ribbon was eliminated in bonded magnet fabrication. The spherical geometry of HPGA powders is more ideal for processing of bonded permanent magnets since higher loading fractions can be obtained during compression and injection molding. This increased volume loading of spherical PM powder can be predicted to yield a higher maximum energy product (BH){sub max} for bonded magnets in high performance applications. Passivation of RE-containing powder is warranted for the large-scale manufacturing of bonded magnets in applications with increased temperature and exposure to humidity. Irreversible magnetic losses due to oxidation and corrosion of particulates is a known drawback …

Transition metal silicides are being considered for future engine turbine components at temperatures up to 1600 C. Although significant improvement in high temperature strength, room temperature fracture toughness has been realized in the past decade, further improvement in oxidation resistance is needed. Oxidation mechanism of Ti{sub 5}Si{sub 3}-based alloys was investigated. Oxidation behavior of Ti{sub 5}Si{sub 3}-based alloy strongly depends on the atmosphere. Presence of Nitrogen alters the oxidation behavior of Ti{sub 5}Si{sub 3} by nucleation and growth of nitride subscale. Ti{sub 5}Si{sub 3.2} and Ti{sub 5}Si{sub 3}C{sub 0.5} alloys exhibited an excellent oxidation resistance in nitrogen bearing atmosphere due to limited dissolution of nitrogen and increased Si/Ti activity ratio. MoSi{sub 2} coating developed by pack cementation to protect Mo-based Mo-Si-B composites was found to be effective up to 1500 C. Shifting coating composition to T1+T2+Mo{sub 3}Si region showed the possibility to extend the coating lifetime above 1500 C by more than ten times via formation of slow growing Mo{sub 3}Si or T2 interlayer without sacrificing the oxidation resistance of the coating. The phase equilibria in the Nb-rich portion of Nb-B system has been evaluated experimentally using metallographic analysis and differential thermal analyzer (DTA). It was shown that Nb{sub ss} …

A measurement of the top quark mass in t{bar t} {yields} l + jets candidate events, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncertainty of the jet momentum reconstruction. As with all matrix elements techniques, the method involves an integration using the Standard Model matrix element for tt production and decay. however, the technique presented is unique in that the matrix element is modified to compensate for kinematic assumptions which are made to reduce computation time. Background events are dealt with through use of an event observable which distinguishes signal from background, as well as through a cut on the value of an event's maximum likelihood. Results are based on a 955 pb{sup -1} data sample, using events with a high-p{sub T} lepton and exactly four high-energy jets, at least one of which is tagged as coming from a …

Macromolecular interactions are essential for virtually all cellular functions including signal transduction processes, metabolic processes, regulation of gene expression and immune responses. This dissertation focuses on the characterization of two important macromolecular interactions involved in the relationship between Equine Infectious Anemia Virus (EIAV) and its host cell in horse: (1) the interaction between the EIAV Rev protein and its binding site, the Rev-responsive element (RRE) and (2) interactions between equine MHC class I molecules and epitope peptides derived from EIAV proteins. EIAV, one of the most divergent members of the lentivirus family, has a single-stranded RNA genome and carries several regulatory and structural proteins within its viral particle. Rev is an essential EIAV regulatory encoded protein that interacts with the viral RRE, a specific binding site in the viral mRNA. Using a combination of experimental and computational methods, the interactions between EIAV Rev and RRE were characterized in detail. EIAV Rev was shown to have a bipartite RNA binding domain contain two arginine rich motifs (ARMs). The RRE secondary structure was determined and specific structural motifs that act as cis-regulatory elements for EIAV Rev-RRE interaction were identified. Interestingly, a structural motif located in the high affinity Rev binding site is …

We study the behavior of charged particles produced in association with Drell-Yan lepton-pairs in the region of the Z-boson in proton-antiproton collisions at 1.96 TeV. We use the direction of the Z-boson in each event to define 'toward', 'away', and 'transverse' regions. For Drell-Yan production (excluding the leptons) both the 'toward' and 'transverse' regions are very sensitive to the 'underlying event', which is defined as everything except the two hard scattered components. The data are corrected to the particle level and are then compared with several PYTHIA models (with multiple parton interactions) and HERWIG (without multiple parton interactions) at the particle level (i.e. generator level). The data are also compared with a previous analysis on the behavior of the 'underlying event' in high transverse momentum jet production. The goal is to produce data that can be used by the theorists to tune and improve the QCD Monte-Carlo models of the 'underlying event' that are used to simulate hadron-hadron collisions.

This dissertation documents the development of a broadband electron spectrometer (ESM) for GeV class Laser Wakefield Accelerators (LWFA), the production of high quality GeV electron beams (e-beams) for the first time in a LWFA by using a capillary discharge guide (CDG), and a statistical analysis of CDG-LWFAs. An ESM specialized for CDG-LWFAs with an unprecedented wide momentum acceptance, from 0.01 to 1.1 GeV in a single shot, has been developed. Simultaneous measurement of e-beam spectra and output laser properties as well as a large angular acceptance (> {+-} 10 mrad) were realized by employing a slitless scheme. A scintillating screen (LANEX Fast back, LANEX-FB)--camera system allowed faster than 1 Hz operation and evaluation of the spatial properties of e-beams. The design provided sufficient resolution for the whole range of the ESM (below 5% for beams with 2 mrad divergence). The calibration between light yield from LANEX-FB and total charge, and a study on the electron energy dependence (0.071 to 1.23 GeV) of LANEX-FB were performed at the Advanced light source (ALS), Lawrence Berkeley National Laboratory (LBNL). Using this calibration data, the developed ESM provided a charge measurement as well. The production of high quality electron beams up to 1 GeV …

The Mini-Booster neutrino experiment (MiniBooNE) at Fermi National Accelerator Laboratory (Fermilab) is designed to search for {nu}{sub {mu}} {yields} {nu}{sub e} appearance neutrino oscillations. Muon neutrino charged-current quasi-elastic (CCQE) interactions ({nu}{sub {mu}} + n {yields} {mu} + p) make up roughly 40% of our data sample, and it is used to constrain the background and cross sections for the oscillation analysis. Using high-statistics MiniBooNE CCQE data, the muon-neutrino CCQE cross section is measured. The nuclear model is tuned precisely using the MiniBooNE data. The measured total cross section is {sigma} = (1.058 {+-} 0.003 (stat) {+-} 0.111 (syst)) x 10{sup -38} cm{sup 2} at the MiniBooNE muon neutrino beam energy (700-800 MeV). {nu}{sub e} appearance candidate data is also used to search for Lorentz violation. Lorentz symmetry is one of the most fundamental symmetries in modern physics. Neutrino oscillations offer a new method to test it. We found that the MiniBooNE result is not well-described using Lorentz violation, however further investigation is required for a more conclusive result.

The thesis is organized as follows: Chapter 1 describes the theoretical framework of non-leptonic B{sub (s)}{sup 0} {yields} H{sup +}h{prime}{sup -} decays, with a simple overview of the CP violation mechanism within the Standard Model and of the most used phenomenological approaches in the evaluation of strong interaction contributions. The chapter contains also a review of the theoretical expectations and the current experimental measurements along with a discussion about the importance of studying such decays. Chapter 2 contains a general description of the Tevatron collider and of the CDF II detector. Chapter 3 is devoted to the description of the data sample used for the measurement and the method used in extracting the signal from the background. Particular attention is dedicated to the on-line trigger selection, which is crucial to collect a sample enriched in B{sub (s)}{sup 0} {yields} h{sup +}h{prime}{sup -} decays. Chapter 4 shows how the information from kinematics and particle identification was used to achieve a statistical discrimination amongst modes to extract individual measurements. The available resolutions in mass or in particle identification are separately insufficient for an event-by-event separation of B{sub (s)}{sup 0} {yields} h{sup +}h{prime}{sup -} modes. The choice of observables and the technique used …

It is now widely accepted that the Standard Model assumption of massless neutrinos is wrong, due primarily to the observation of solar and atmospheric neutrino flavor oscillations by a small number of convincing experiments. The MINOS Far Detector, capable of observing both the outgoing lepton and associated showering products of a neutrino interaction, provides an excellent opportunity to independently search for an oscillation signature in atmospheric neutrinos. To this end, a MINOS data set from an 883 live day, 13.1 kt-yr exposure collected between July, 2003 and April, 2007 has been analyzed. 105 candidate charged current muon neutrino interactions were observed, with 120.5 {+-} 1.3 (statistical error only) expected in the absence of oscillation. A maximum likelihood analysis of the observed log(L/E) spectrum shows that the null oscillation hypothesis is excluded at over 96% confidence and that the best fit oscillation parameters are sin{sup 2} 2{theta}{sub 23} = 0.95{sub -0.32} and {Delta}m{sub 23}{sup 2} = 0.93{sub -0.44}{sup +3.94} x 10{sup -3} eV{sup 2}. This measurement of oscillation parameters is consistent with the best fit values from the Super-Kamiokande experiment at 68% confidence.

The formation of surface undulations (i.e. rumpling) at the bond coat/thermally grown oxide (TGO) interface has been shown to cause failure by spallation of the ceramic top coat in aero-turbine systems. Many mechanisms have been proposed concerning the cause of these surface distortions; however, there is little agreement on what may be the dominating cause of the rumpling behavior. Of there mechanisms, the reversible phase transformation from a cubic {beta}-NiAl structure to a face centered tetragonal (FCT) martensitic phase was of particular interest because of its ability to form surface rumpling in Pt-modified {beta} bulk alloys. However, the bulk alloys used in obtaining that result were simple ternary systems and not relevant to actual coating compositions as other alloying elements enter the coating due to coating/substrate interdiffusion at high temperature. In the current study, the depletion behavior of a commercial coating was studied. Compositions from the depletion path were determined and bulk alloys representing these coating compositions were prepared. The martensitic phase transformation was then characterized using DSC and XRD. The martensitic start temperature on cooling, Ms, was consistently found to be significantly lower than previously reported values (e.g. 530 C vs 100 C). Because of the low Ms temperature, …

Sum frequency generation (SFG) vibrational spectroscopy has been used to study the interfacial structure of several polypeptides and amino acids adsorbed to hydrophobic and hydrophilic surfaces under a variety of experimental conditions. Peptide sequence, peptide chain length, peptide hydrophobicity, peptide side-chain type, surface hydrophobicity, and solution ionic strength all affect an adsorbed peptide's interfacial structure. Herein, it is demonstrated that with the choice of simple, model peptides and amino acids, surface specific SFG vibrational spectroscopy can be a powerful tool to elucidate the interfacial structure of these adsorbates. Herein, four experiments are described. In one, a series of isosequential amphiphilic peptides are synthesized and studied when adsorbed to both hydrophobic and hydrophilic surfaces. On hydrophobic surfaces of deuterated polystyrene, it was determined that the hydrophobic part of the peptide is ordered at the solid-liquid interface, while the hydrophilic part of the peptide appears to have a random orientation at this interface. On a hydrophilic surface of silica, it was determined that an ordered peptide was only observed if a peptide had stable secondary structure in solution. In another experiment, the interfacial structure of a model amphiphilic peptide was studied as a function of the ionic strength of the solution, a …

In a universe dominated by matter, the source of CP violation may explain one of the greatest mysteries in particle physics: what happened to the antimatter? The Standard Model successfully describes CP violation in the B{sup +} and B{sub d}{sup 0} systems, yet insufficiently accounts for the observed matter-antimatter asymmetry. The Standard Model predicts a small value of CP violation in the B{sub s}{sup 0} meson system, which has only recently been experimentally tested. A measurement of large, anomalous CP violation in the B{sub s}{sup 0} system would be a clear indication of new physics sources beyond the Standard Model. This dissertation describes a study of CP violation in approximately 2000 B{sub s}{sup 0} {yields} J/{psi}{phi} decays reconstructed in a 2.8 fb{sup -1} data sample collected by the D0 Run II detector at Fermi National Accelerator Laboratory in Batavia, Illinois. This data was provided by p{bar p} collisions at {radical}s = 1.96 TeV delivered by the Tevatron accelerator between April 2002 and August 2007. Flavor-tagged B{sub s}{sup 0} {yields} J/{psi}({mu}{sup +}{mu}{sup -}){phi}(K{sup +}K{sup -}) decays and an angular analysis are used to study the time evolution of the final state angular distributions. From this analysis, we measure the width difference …

This dissertation presents the results of a research agenda aimed at improving integration and stability in nanocrystal-based solar cells through advances in active materials and device architectures. The introduction of 3-dimensional nanocrystals illustrates the potential for improving transport and percolation in hybrid solar cells and enables novel fabrication methods for optimizing integration in these systems. Fabricating cells by sequential deposition allows for solution-based assembly of hybrid composites with controlled and well-characterized dispersion and electrode contact. Hyperbranched nanocrystals emerge as a nearly ideal building block for hybrid cells, allowing the controlled morphologies targeted by templated approaches to be achieved in an easily fabricated solution-cast device. In addition to offering practical benefits to device processing, these approaches offer fundamental insight into the operation of hybrid solar cells, shedding light on key phenomena such as the roles of electrode-contact and percolation behavior in these cells. Finally, all-inorganic nanocrystal solar cells are presented as a wholly new cell concept, illustrating that donor-acceptor charge transfer and directed carrier diffusion can be utilized in a system with no organic components, and that nanocrystals may act as building blocks for efficient, stable, and low-cost thin-film solar cells.