The primary mode of production of W{sup +} bosons in a p{bar p} collider is u + {bar d} {yields} W{sup +}. The u quark generally carries more momentum than the {bar d} and the resultant W{sup +} tends to be boosted in the proton direction. Similarly, W bosons are boosted in the anti-proton direction. This is observed as an asymmetry in the rapidity distributions of positive and negative W bosons. Measurement of this asymmetry serves as a probe of the momentum distribution of partons within the proton. These distributions are required as input to the calculation of every p{bar p} production cross section. This thesis presents the first measurement at D0 of the charge asymmetry of the W boson production cross section as measured in W {yields} ev decays in 0.3 fb{sup -1} of p{bar p} collisions collected with the D0 Detector. Theoretical predictions made using the CTEQ6.1M and MRST(2004) parton distribution functions are compared with the measurement.

The problem of the bimolecular rate constant, alpha , for the mutual charge neutralization reaction (ion-ion recombination) for ions formed by the vacuum ultraviolet photolysis of nitric oxide is considered. The pressure dependence of alpha over a pressure range of 10 to 600 torr for mixtures of a few hundred microns of NO with He, Ar, Kr, Xe, H/sub 2/, D/sub 2/, and N/sub 2/ was measured. From the low-pressure limit of alpha , the rate constant for charge neutralization in the absence of a third body was found to be k/sub o/ = 2.1 plus or minus 0.4 x 10/sup -7/ cm/sup 3// sec. The high-pressure limit of alpha was estimated to be 2.0 plus or minus 0.5 x 10/sup -6/ cm/sup 3//sec. The third-body efficiencies for promoting the charge-neutralization reaction were measured. The results, relative to He as the third-body gas, are H/sub 2/= 1.4 plus or minus 0.4, D/sub 2/= 1.5 plus or minus 0.4, Ar =3.6 plus or minus 0.8, Kr =4.3 plus or min11.0, N/sub 2/ = 5.2 plus or minus 1.1, and Xe = 6.8 plus or minus 1.5. The average ionic mobility in the gas mixtures is estimated, and the mobilities indicate that …

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A chemical synthesis route is discussed which results in a low- temperature precursor to Y-Ba-Cu-O ceramics; it is based on use of molten Ba(OH){sub 2}{center_dot}8H{sub 2}O flux. Two different chemical systems have been examined; the first one, based on nitrate salts, has been demonstrated to be a viable precursor material for tape casting and extrusion; the second, made from acetate salts, has been used for powder synthesis and extrusion. Rheology of pastes shows that their flow may be fit to either Bingham Plastic or Hershel- Bulkley models. Yield stress is controlled in both pastes by volume fraction solids. Viscosity also follows solids loading in the paste. Shear thinning is controlled by colloidal nature of precursor. The paste has colloidal microstructure. Comparison of concentric cylinder rheometry and piston extrusion rheometry shows order of magnitude differences in yield stress, resulting from the test method and paste dilation.

Smooth particle methods are relatively new methods for simulating solid and fluid flows through they have a 20-year history of solving complex hydrodynamic problems in astrophysics, such as colliding planets and stars, for which correct answers are unknown. The results presented in this thesis evaluate the adaptability or fitness of the method for typical hydrocode production problems. For finite hydrodynamic systems, boundary conditions are important. A reflective boundary condition with image particles is a good way to prevent a density anomaly at the boundary and to keep the fluxes continuous there. Boundary values of temperature and velocity can be separately controlled. The gradient algorithm, based on differentiating the smooth particle expression for (u{rho}) and (T{rho}), does not show numerical instabilities for the stress tensor and heat flux vector quantities which require second derivatives in space when Fourier`s heat-flow law and Newton`s viscous force law are used. Smooth particle methods show an interesting parallel linking to them to molecular dynamics. For the inviscid Euler equation, with an isentropic ideal gas equation of state, the smooth particle algorithm generates trajectories isomorphic to those generated by molecular dynamics. The shear moduli were evaluated based on molecular dynamics calculations for the three weighting functions, …

Better devices are needed for the detection of aerosolized biological warfare agents. Advances in the ongoing development of one such device, the BioAerosol Mass Spectrometry (BAMS) system, are described here in detail. The system samples individual, micrometer-sized particles directly from the air and analyzes them in real-time without sample preparation or use of reagents. At the core of the BAMS system is a dual-polarity, single-particle mass spectrometer with a laser based desorption and ionization (DI) system. The mass spectra produced by early proof-of-concept instruments were highly variable and contained limited information to differentiate certain types of similar biological particles. The investigation of this variability and subsequent changes to the DI laser system are described. The modifications have reduced the observed variability and thereby increased the usable information content in the spectra. These improvements would have little value without software to analyze and identify the mass spectra. Important improvements have been made to the algorithms that initially processed and analyzed the data. Single particles can be identified with an impressive level of accuracy, but to obtain significant reductions in the overall false alarm rate of the BAMS instrument, alarm decisions must be made dynamically on the basis of multiple analyzed particles. …

Stability of a cylindrical pore under the influence of surface energy is important for porous silicon (PS) processing in the integrated circuit industry. Once the zig-zag cylindrical pores of porous silicon or oxidized porous silicon (OPS) are unstable and breakup into rows of isolated spherical pores, oxidation of PS and densification/nitridation of OPS become difficult. Swing to difficulty transport of reactant gas (O{sub 2}, NH{sub 3}) or the trapped gas (for densification of OPS). A first order analysis of the stability of a cylindrical pore or cylinder is considered first. Growth of small sinusoidal perturbations by viscous flow or evaporation/condensation result in dependence of perturbation growth rate on perturbation wavelength. Rapid thermal oxidation (RTO) of porous silicon is proposed as an alternative for the tedious two-step 300 and 800C oxidation process. Transmission electron microscopy, energy dispersive spectroscopy ESCA are used for quality control. Also, rapid thermal nitridation of oxidized porous silicon in ammonia is proposed to enhance OPS resistance to HF solution. Pores breakup of OPS results in a trapped gas problem during densification. Wet helium is proposed as OPS densification ambient gas to shorten densification time. Finally, PS is proposed to be an extrinsic gettering center in silicon wafers. …

A study of events with Z={gamma}* bosons and hadronic jets produced at the Tevatron in p{bar p} collisions at a center of mass energy of 1.96 TeV is presented. The data consist of approximately 14,000 Z/{gamma}* {yields} e{sup +}e{sup -} decay candidates from 343 pb{sup -1} of integrated luminosity collected with the D0 detector. Cross sections and jet production properties have been measured for Z/{gamma}* + {ge} 0 to 5 jet events. This measurement represents a significant improvement over previous measurements at the Tevatron, and it is the first at this center of mass energy with the D0 detector. The results are in good agreement with QCD predictions.

This thesis is dedicated to the study of the first data taken by the D0 detector during the Run II of the Tevatron. Supersymmetric particles have been search for in proton-antiproton collisions, with a center of mass energy of 1.96 TeV. In the framework of supersymmetry with R-parity violation, I have studied the pair production of Gauginos, leading to a pair of LSP ({chi}{sub 1}{sup 0}), each one decaying into ee{nu}{sub {mu}} or e{mu}{nu}{sub e} with a {lambda}{sub 121} coupling. The final state contains at least two electrons: I have thus paid special attention in this work to the methods concerning identification and mis-identification of electromagnetic particles, as well as reconstruction, triggering, and correction (of the reconstructed energy). In a selection of trileptons, with at least two electrons, and some transverse missing energy, we observed 0 event in the 350 pb{sup -1} of analyzed data, for 0,4{sub -0,05}{sup +0,35}(stat) {+-} 0,16 (sys) expected from the Standard Model contributions. In the signal considered in this analysis, the selection efficiency is around 12%. Results have been studied in two models: mSUGRA and MSSM. In mSUGRA model, limits on m{sub 1/2} and lightest gauginos's masses have been obtained, with tan{beta} = 5, A{sub …