This thesis investigates the use of a fast imaging technique to deduce the spatial conductivity distribution in the earth from low frequency (< 1 MHz), cross well electromagnetic (EM) measurements. The theory embodied in this work is the extension of previous strategies and is based on the Born series approximation to solve both the forward and inverse problem. Nonlinear integral equations are employed to derive the series expansion which accounts for the scattered magnetic fields that are generated by inhomogeneities embedded in either a homogenous or a layered earth. A sinusoidally oscillating, vertically oriented magnetic dipole is employed as a source, and it is assumed that the scattering bodies are azimuthally symmetric about the source dipole axis. The use of this model geometry reduces the 3-D vector problem to a more manageable 2-D scalar form. The validity of the cross well EM method is tested by applying the imaging scheme to two sets of field data. Images of the data collected at the Devine, Texas test site show excellent correlation with the well logs. Unfortunately there is a drift error present in the data that limits the accuracy of the results. A more complete set of data collected at the …

The N-body problem is to simulate the motion of N particles under the influence of mutual force fields based on an inverse square law. The problem has applications in several domains including astrophysics, molecular dynamics, fluid dynamics, radiosity methods in computer graphics and numerical complex analysis. Research efforts have focused on reducing the O(N{sup 2}) time per iteration required by the naive algorithm of computing each pairwise interaction. Widely respected among these are the Barnes-Hut and Greengard methods. Greengard claims his algorithm reduces the complexity to O(N) time per iteration. Throughout this thesis, we concentrate on rigorous, distribution-independent, worst-case analysis of the N-body methods. We show that Greengard`s algorithm is not O(N), as claimed. Both Barnes-Hut and Greengard`s methods depend on the same data structure, which we show is distribution-dependent. For the distribution that results in the smallest running time, we show that Greengard`s algorithm is {Omega}(N log{sup 2} N) in two dimensions and {Omega}(N log{sup 4} N) in three dimensions. We have designed a hierarchical data structure whose size depends entirely upon the number of particles and is independent of the distribution of the particles. We show that both Greengard`s and Barnes-Hut algorithms can be used in conjunction with …

Absolute yields of CO, CO{sub 2}, and H{sub 2}CO formed in reaction of triplet methylene ({tilde X} {sup 3}B{sub 1} {triple_bond} CH{sub 2}) with O{sub 2} were determined using a flash kinetic spectrometer. CH{sub 2} radicals were generated by excimer laser photolysis of ketene and product formation was monitored by time-resolved infrared diode laser absorption. Reaction was carried out in a static gas cell at room temperature at 1--25 torr. Measured product yields were CO, 0.34 {plus_minus} 0.06; CO{sub 2}, 0.40 {plus_minus} 0.08 H{sub 2}CO, 0.16 {plus_minus} 0.04. Rate constants for production of CO and CO{sub 2} were equivalent to the published rate constant for removal of CH{sub 2}. Indirect evidence indicated that yield of OH is 0.30 {plus_minus} 0.05. Ultraviolet spectrum of methyl isothiocyanate (CH{sub 3}NCS {triple_bond} MITC) and quantum yield for dissociation into methyl isocyanide (CH{sub 3}NC) and atomic sulfur at 308 nm, {Phi} 0.98 {plus_minus} 0.24, were measured. MITC is widely used as a fumigant and readily enters the atmosphere during and after application. Results indicate that photodissociation by sunlight is an effective pathway for removal of MITC from atmosphere. A mechanism is proposed to account for the observed formation of methyl isocyanate (CH{sub 3}NCO) as a …

A desolvation scheme for introducing aqueous and organic samples into an argon inductively coupled plasma is described; the aerosol generated by nebulizer is heated (+140 C) and cooled ({minus}80 C) repeatedly, and the dried aerosol is then injected into the mass spectrometer. Polyatomic ions are greatly suppressed. This scheme was validated with analysis of seawater and urine reference samples. Finally, the removal of organic solvents by cryogenic desolvation was studied.

The effect of process parameters and chemical additives on the specific cake resistance of zinc hydroxide precipitates was investigated. The ability of a slurry to be filtered is dependent upon the particle habit of the solid and the particle habit is influenced by certain process variables. The process variables studied include neutralization temperature, agitation type, and alkalinity source used for neutralization. Several commercially available chemical additives advertised to aid in solid/liquid separation were also examined in conjunction with hydroxide precipitation. A statistical analysis revealed that the neutralization temperature and the source of alkalinity were statistically significant in influencing the specific cake resistance of zinc hydroxide precipitates in this study. The type of agitation did not significantly effect the specific cake resistance of zinc hydroxide precipitates. The use of chemical additives in conjunction with hydroxide precipitation had a favorable effect on the filterability. The morphology of the hydroxide precipitates was analyzed using scanning electron microscopy.

By definition a plasma is an electrically conducting gaseous mixture containing a significant concentration of cations and electrons. The Inductively Coupled Plasma (ICP) is an electrodeless discharge in a gas at atmospheric pressure. This discharge is an excellent one for vaporizing, atomizing, and ionizing elements. The early development of the ICP began in 1942 by Babat and then by Reed in the early 1960s. This was then followed by the pioneering work of Fassel and coworkers in the late 1960s. Commercial ICP spectrometers were introduced in the mid 1970s. A major breakthrough in the area of ICP took place in the early 1980s when the ICP was shown to be an excellent ion source for mass spectrometry.

This report contains a general introduction which discusses solid-phase extraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phase extraction; a new, high-capacity carboxylic acid functionalized resin for solid-phase extraction; semi-micro solid-phase extraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.

Jefferson Lab kaon experiments E91016/E93018 produced data on both strangeness and vector meson electroproduction. The latter part of the experiments was focused on the electroproduction of the omega meson for momentum transfer Q 2 near 0.5 (GeV/c) 2. This reaction was selected from the inelastic ep channel, H-1 (e, e' p)X, by performing involved signal background separation. Tagging the omega meson production only on electron and proton not only introduced appreciable statistical error but also a sizeable systematic uncertainty due to the background removal. Nevertheless, the analysis yielded angular distributions of the differential cross section in the threshold regime extracted with an unprecedented granularity and relatively small errors.

CDF (Collider Detector at Fermilab) is a particle detector located at Fermi National Laboratories, near Chicago. it allows to study decay products of p{bar p} collisions at center-of-mass energy of 1.96 TeV. During its first period of data taking (RunI), CDF observed for the first time the top quark (1995). The current period of data taking (RunII) is devoted to precise measurements of top properties and to search for new physics. This thesis work is about the top decay channel named {tau} + jets. A t{bar t} pair decays in two W bosons and two b quarks. In a {tau} + jets event, one out of the two W decays into two jets of hadrons, while the other produces a {tau} lepton and a neutrino; the {tau} decays semileptonically in one or more charged and neutral pions while b quarks hadronize producing two jets of particles. Thus the final state of a {tau} + jets event has this specific signature: five jets, one {tau}-like, i.e. narrow and with low track multiplicity, two from b quarks, two from a W boson and a large amount of missing energy from two {tau} neutrinos. They search for this signal in 311 pb{sup -1} …

Perfluoro ionomer membranes are tetrafluoro ethylene-based materials with microheterogeneous structures consisting of a hydrophobic polymer backbone and a hydrophilic side-chain cluster region. Due to the ionomer cluster morphology, these films exhibit unique transport properties. Recent investigations with perfluoro sulfonate and perfluoro sulfonate/carboxylate composite polymers have demonstrated their value in the dehydration of nitric acid and they show potential as an alternative to conventional, energy intensive unit operations in the concentration of acid feeds. As a result, investigations were conducted to determine the feasibility of using pure perfluoro carboxylate and mixed perfluoro sulfonate/carboxylate films for the dehydration of nitric acid because of the speculation of improved water selectivity of the carboxylate pendant chain. During the first phase of these investigations the effort was focused on generating a thin, solution cast perfluoro carboxylate ionomer film, to evaluate the general, chemical and physical characteristics of the polymer, and to assess the material's aqueous transport performance (flux and nitrate separation efficiencies) in pervaporation and high-pressure environments. Results demonstrated that generating robust solution-cast films was difficult yet a number of membranes survived high trans-membrane pressures up to 700 psig. General characterization of the solution cast product showed reduced ion exchange capacities when compared with thicker, …

The potential for contamination of groundwater by organic pollutants leached from in-situ spent shale was studied in a series of laboratory leaching experiments. Both batch-mode and continuous-flow column experiments were conducted to study the leaching phenomenon. Experimental variables included retorting characteristics of spent shale, leaching time, initial quality of leach water, temperature of leach water, and particle size of spent shale. Several unique samples of spent shale were examined during the eaching experiments, including spent shale samples produced during combustion retorting, inert gas retorting, and combustion retorting employing recycle gas. The solid-phase organic carbon content of spent shale samples ranged from 0.2 to 3.9 percent by weight. Leachate derived from the batch-mode experiments was analyzed for organic carbon, organic nitrogen, phenols, and acid/base/netral fractions. The highest levels of organic carbon were detected in leachate derived from spent shale produced during either inert gas retorting or combstion retorting using recycle gas. The highest levels of phenols were observed in leachate obtained from spent shale produced during inert gas retorting; significant levels of organic nitrogen were also detected in various leachate samples. The most predominant organic fraction measured in leachate samples was the neutral fraction associated with spent shale produced during inert …

An injector is a particular type of jet pump which uses condensable vapor to entrain a liquid and discharge against a pressure higher than either motive or suction pressures. The injector has no moving parts and requires no external power supply nor any complex control system. Thus, the injector is particularly suited for emergency core cooling operations. A detailed survey has indicated that various injector designs are available for operating pressures below 250 psig. However, the design of these injectors from the viewpoint of a basic understanding of heat and mass transfer processes has not been well developed. A critical review of the models showed serious discrepancies between the analytical models and the experimental observations. The discrepancies evolved from the neglect of non-equilibrium aspects of the flow. The origin of the non-equilibrium aspects can be traced to the extremely small time scales governing the flow in the injector. Thus, time scales of the order of 10{sup {minus}2} seconds are involved in the injector, accompanied by mass, momentum, and heat transfer rates of orders of magnitude higher than that observed in conventional two-phase flows. The present study focuses on the phenomenological and mathematical modeling of the processes in the injector from …

All known experimental results on fundamental particles and their interactions can be described to great accuracy by a theory called the Standard Model. In the Standard Model of particle physics, the masses of particles are explained through the Higgs mechanism. The Higgs boson is the only Standard Model particle not discovered yet, and its observation or exclusion is an important test of the Standard Model. While the Standard Model predicts that a Higgs boson should exist, it does not exactly predict its mass. Direct searches have excluded a Higgs with m{sub H} &lt; 114.4 GeV at 95% confidence level, while indirect measurements indicate that the mass should be less than 144 GeV. This analysis looks for W{sup {+-}}H {yields} {mu}{nu}{sub {mu}}b{bar b} in 1 fb{sup -1} of data collected with the D0 detector in p{bar p} collisions with {radical}s = 1.96 TeV. The analysis strategy relies on the tracking, calorimetry and muon reconstruction of the D0 experiment. The signature is a muon, missing transverse energy (E{sub T}) to account for the neutrino and two b-jets. The Higgs mass is reconstructed using the invariant mass of the two jets. Backgrounds are W{sup {+-}}b{bar b}, W{sup {+-}} c{bar c}, W{sup {+-}} + …

The Standard Model describes with a very good accuracy all interactions of the, so far, known elementary particles. However the Higgs mechanism, which gives rise to the observed mass of these particles, has not yet been confirmed. The Higgs particle has not yet been observed, and the observation or exclusion is an important test of the Standard Model. The Standard Model does not predict the mass of the Higgs particle, however it does impose some limits on the range in which this mass can lie. In direct searches a Higgs with a mass smaller than 114.4 GeV and within 162 GeV and 166 GeV has been excluded at 95% CL at the LEP and the Tevatron colliders. The analysis presented in this thesis is aimed to search for the ZH → μμb$\bar{b}$ events in 3.1 fb^-1 of data collected with the DØ detector in p$\bar{p}$ collisions at √s = 1.96 TeV.

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This thesis is a description of the measurement of the W boson mass using the D0 Run II detector with 770 pb{sup -1} of p{bar p} collision data. These collisions were produced by the Tevatron at {radical}s = 1.96 TeV between 2002 and 2006. We use a sample of W {yields} e{nu} and Z {yields} ee decays to determine the W boson mass with the transverse momentum distribution of the electron and the transverse mass distribution of the boson. We measure M{sub W} = XXXXX {+-} 37 (stat.) {+-} 26 (sys. theo.) {+-} 51 (sys. exp.) MeV = XXXXX {+-} 68 MeV with the transverse momentum distribution of the electron and M{sub W} = XXXXX {+-} 28 (stat.) {+-} 17 (sys. theo.) {+-} 51 (sys. exp.) MeV = XXXXX {+-} 61 MeV with the transverse mass distribution.

This work attempts to show the feasibility of nondestructive characterization of non-ferrous alloys. Aluminum alloys have a small single crystal anisotropy which requires very precise ultrasonic velocity measurements for derivation of orientation distribution coefficients (ODCs); the precision in the ultrasonic velocity measurement required for aluminum alloys is much greater than is necessary for iron alloys or other alloys with a large single crystal anisotropy. To provide greater precision, some signal processing corrections need to be applied to account for the inherent, half-bandwidth offset in triggered pulses when using a zero-crossing technique for determining ultrasonic velocity. In addition, alloys with small single crystal anisotropy show a larger dependence on the single crystal elastic constants (SCECs) when predicting ODCs which require absolute velocity measurements. Attempts were made to independently determine these elastics constants in an effort to improve correlation between ultrasonically derived ODCs and diffraction derived ODCs. The greater precision required to accurately derive ODCs in aluminum alloys using ultrasonic nondestructive techniques is easily attainable. Ultrasonically derived ODCs show good correlation with derivations made by Bragg diffraction techniques, both neutron and X-ray. The best correlation was shown when relative velocity measurements could be used in the derivations of the ODCs. Calculation of …

X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Ignition Facility (NIF). Accurate knowledge of the x-ray and debris emissions from ICF targets is a critical first step in the process of predicting the performance of the target chamber system. A number of 1-D numerical simulations of NIF targets have been run to characterize target output in terms of energy, angular distribution, spectrum, and pulse shape. Scaling of output characteristics with variations of both target yield and hohlraum wall thickness are also described. Experiments have been conducted at the Nova laser on the effects of relevant x-ray fluences on various materials. The response was diagnosed using post-shot examinations of the surfaces with scanning electron microscope and atomic force microscope instruments. Judgments were made about the dominant removal mechanisms for each material. Measurements …

The underlying theme of this thesis is the use of polymeric materials in bioapplications. Chapters 2-5 either develop a fundamental understanding of current materials used for bioapplications or establish protocols and procedures used in characterizing and synthesizing novel materials. In chapters 6 and 7 these principles and procedures are applied to the development of materials to be used for gene therapy and drug delivery. Chapter one is an introduction to the ideas that will be necessary to understand the subsequent chapters, as well as a literature review of these topics. Chapter two is a paper that has been published in the ''Journal of Controlled Release'' that examines the mechanism of drug release from a polymer gel, as well as experimental design suggestions for the evaluation of water soluble drug delivery systems. Chapter three is a paper that has been published in the ''Journal of Pharmaceutical Sciences'' that discusses the effect ionic salts have on properties of the polymer systems examined in chapter two. Chapter four is a paper published in the Materials Research Society Fall 2000 Symposium Series dealing with the design and synthesis of a pH-sensitive polymeric drug delivery device. Chapter five is a paper that has been published …

The work described in this dissertation has improved three essential components of extreme ultraviolet (EUV) lithography: exposure tools, photoresist, and metrology. Exposure tools. A field-averaging illumination stage is presented that enables nonuniform, high-coherence sources to be used in applications where highly uniform illumination is required. In an EUV implementation, it is shown that the illuminator achieves a 6.5% peak-to-valley intensity variation across the entire design field of view. In addition, a design for a stand-alone EUV printing tool capable of delivering 15 nm half-pitch sinusoidal fringes with available sources, gratings and nano-positioning stages is presented. It is shown that the proposed design delivers a near zero line-edge-rougness (LER) aerial image, something extremely attractive for the application of resist testing. Photoresist. Two new methods of quantifying the deprotection blur of EUV photoresists are described and experimentally demonstrated. The deprotection blur, LER, and sensitivity parameters of several EUV photoresists are quantified simultaneously as base weight percent, photoacid generator (PAG) weight percent, and post-exposure bake (PEB) temperature are varied. Two surprising results are found: (1) changing base weight percent does not significantly affect the deprotection blur of EUV photoresist, and (2) increasing PAG weight percent can simultaneously reduce LER and E-size in EUV …

Elucidating the nature of neutrino oscillation continues to be a goal in the vanguard of the efforts of physics experiment. As neutrino oscillation searches seek an increasingly elusive signal, a thorough understanding of the possible backgrounds becomes ever more important. Measurements of neutrino-nucleus interaction cross sections are key to this understanding. Searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillation - a channel that may yield insight into the vanishingly small mixing parameter {theta}{sub 13}, CP violation, and the neutrino mass hierarchy - are particularly susceptible to contamination from neutral current single {pi}{sup 0} (NC 1{pi}{sup 0}) production. Unfortunately, the available data concerning NC 1{pi}{sup 0} production are limited in scope and statistics. Without satisfactory constraints, theoretical models of NC 1{pi}{sup 0} production yield substantially differing predictions in the critical E{sub {nu}} {approx} 1 GeV regime. Additional investigation of this interaction can ameliorate the current deficiencies. The Mini Booster Neutrino Experiment (MiniBooNE) is a short-baseline neutrino oscillation search operating at the Fermi National Accelerator Laboratory (Fermilab). While the oscillation search is the principal charge of the MiniBooNE collaboration, the extensive data ({approx} 10{sup 6} neutrino events) offer a rich resource with which to conduct neutrino cross section measurements. This work concerns …

An analytic treatment of the one Higgs doublet, electroweak phase transition is given. The phase transition is first order, occurs by the nucleation of thin walled bubbles and completes at a temperature where the order parameter, {l_angle}{phi}{r_angle}{sub T} is significantly smaller than it is when the origin becomes absolutely unstable. The rate of anomalous baryon number violation is an exponentially function of {l_angle}{phi}{r_angle}{sub T}. In very minimal extensions of the standard model it is quite easy to increase {l_angle}{phi}{r_angle}{sub T} so that anomalous baryon number violation is suppressed after completion of the phase transition. Hence baryogenesis at the electroweak phase transition is tenable in minimal of the standard model. In some cases additional phase transitions are possible. For a light Higgs boson, when the top quark mass is sufficiently large, the state where the Higgs field has a vacuum expectation value {l_angle}{phi}{r_angle} = 246 GeV is not the true minimum of the Higgs potential. When this is the case, and when the top quark mass exceeds some critical value, thermal fluctuations in the early universe would have rendered the state {l_angle}{phi}{r_angle} = 246 GeV unstable. The requirement that the state {l_angle}{phi}{r_angle} = 246 GeV is sufficiently long lived constrains the …

Oxygen, nitrogen, and nitric oxide gases were passed through a system consisting of a tungsten filament, an ion gauge, and a mass spectrometer. The ion gauge recorded total pressures and the spectrometer recorded partlal pressures of O/sub 2/, N/sub 2/, NO, CO, COa, and H/sub 2/O. From the way these pressures changed with filamert temperature, the rates of conversion of O/sub 2/ to volatile tungsten oxides and O, and of NO to volatile tungsten oxides N/sub 2/ , O/sub 2/, and O were computed. The time rate of resistance change in the filament was used to compute the rate of conversion of tungsten to tungsten oxides. The filament temperatures ranged from 1950 through 2600 deg K and gas pressures ranged from 10/sup -8/ to 10/sup -6/ atm. For the tungsten-oxygen reaction, the rates of tungsten and oxygen loss were found to depend upon oxygen atom concentration on the surface. The rate of oxide power, depending upon the concentration of oxygen atoms on the surface. The reaction rate at constant oxygen pressure decreases with increasing temperature. For calculational purposes, the tungsten oxygen gas moleeules were assumed to be WO/sub 3/ only, though WO/sub 2/ and WO are other possible products. The …

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