Flight comparison of the transonic agility of the F-111A airplane and the F-111 supercritical wing airplane

A flight research program was conducted to investigate the improvements in maneuverability of an F-111A airplane equipped with a supercritical wing. In this configuration the aircraft is known as the F-111 TACT (transonic aircraft technology) airplane. The variable-wing-sweep feature permitted an evaluation of the supercritical wing in many configurations. The primary emphasis was placed on the transonic Mach number region, which is considered to be the principal air combat arena for fighter aircraft. An agility study was undertaken to assess the maneuverability of the F-111A aircraft with a supercritical wing at both design and off-design conditions. The evaluation included an assessment of aerodynamic and maneuver performance in conjunction with an evaluation of precision controllability during tailchase gunsight tracking tasks

Accurate formation energies of charged defects in solids: a systematic approach

Defects on surfaces of semiconductors have a strong effect on their reactivity and catalytic properties. The concentration of different charge states of defects is determined by their formation energies. First-principles calculations are an important tool for computing defect formation energies and for studying the microscopic environment of the defect. The main problem associated with the widely used supercell method in these calculations is the error in the electrostatic energy, which is especially pronounced in calculations that involve surface slabs and 2D materials. We present an internally consistent approach for calculating defect formation energies in inhomogeneous and anisotropic dielectric environments, and demonstrate its applicability to the cases of the positively charged Cl vacancy on the NaCl (100) surface and the negatively charged S vacancy in monolayer MoS2

An LED pulser for measuring photomultiplier linearity

A light-emitting diode (LED) pulser for testing the low-rate response of a photomultiplier tube (PMT) to scintillator-like pulses has been designed, developed, and implemented. This pulser is intended to simulate 80 ns full width at half maximum photon pulses over the dynamic range of the PMT, in order to precisely determine PMT linearity. This particular design has the advantage that, unlike many LED test rigs, it does not require the use of multiple calibrated LEDs, making it insensitive to LED gain drifts. Instead, a finite-difference measurement is made using two LEDs which need not be calibrated with respect to one another. These measurements give a better than 1% mapping of the response function, allowing for the testing and development of particularly linear PMT bases.Comment: 5 pages, 5 figure

Upgraded photon calorimeter with integrating readout for the Hall A Compton polarimeter at Jefferson Lab

The photon arm of the Compton polarimeter in Hall A of Jefferson Lab has been upgraded to allow for electron beam polarization measurements with better than 1% accuracy. The data acquisition system (DAQ) now includes an integrating mode, which eliminates several systematic uncertainties inherent in the original counting-mode DAQ. The photon calorimeter has been replaced with a Cedoped Gd2SiO5 crystal, the bright output and fast response of which are ideal for measurements using the new integrating method. The upgraded system was used to continuously measure the electron beam polarization during HAPPEX-III, and the results of this high precision measurement are presented

Doctor of Philosophy

dissertationAlthough it is well known that METH damages the dopamine (DA) system, the mechanisms underlying such toxicity have not been elucidated. Previous work indicates that animals with partial DA loss from prior exposure to METH are resistant to further decreases in DA when reexposed to METH 30 days later. This experimental paradigm results in four treatment groups based on postnatal day (PND)60:PND90 treatment (Saline:Saline, METH:Saline, Saline:METH, METH:METH) and allows for examination of factors associated with METH toxicity in animals matched for METH exposure, but differentiated with respect to acute METH neurotoxicity. We used this paradigm to examine factors implicated in METH-induced neurotoxicity. First, we investigated the possible contribution of nitric oxide (NO) by examining nitric oxide synthase (NOS) expression, activity, and protein nitration. We found that acute METH administration increased NO production; however, METH did not change expression of endothelial NOS or result in induction of inducible NOS. The number of cells positive for neuronal (nNOS) mRNA or the amount of nNOS mRNA per cell also did not change. However, NOS activity was increased acutely after METH exposure, suggesting that increased NO production after METH exposure arises from NOS activity and most likely, nNOS. Furthermore, animals resistant to METH-induced DA depletions show equivalent degrees of NO production, suggesting that NO alone is not sufficient to induce METH-induced neurotoxicity. Using the same paradigm, we then examined glial reactivity using glialfibrillary acidic protein (GFAP; astrocytes) and CD11b (Microglia), as well as markers of proliferation (BrdU and Ki67) immunohistochemistry. Animals experiencing acute toxicity (Saline:METH) showed activated microglia and astocytes, whereas those resistant to toxicity (METH:METH) did not show activated microglia. Furthermore, animals experiencing acute toxicity (Saline:METH) also showed increased proliferation compared to all other groups and a large proportion of proliferating cells were microglia with a smaller proportion being astrocytes. Interestingly, GFAP expression remained elevated in animals exposed to METH at PND60 (METH:Saline), and was not further elevated in resistant animals (METH:METH). These data suggest that astrocytes remain reactive up to 30 days post-METH exposure and that astrocyte reactivity does not reflect acute METH-induced neurotoxicity whereas microglial reactivity parallels acute METHinduced neurotoxicity

Cyber Bullying Evolved: Bullying in the Military Workcenter

The purpose of this project was to inform readers about the progression of cyber bullying into the military work center. This research has been compiled to aid the thesis topic for the capstone project in the Regis University Criminology program. The proposal relates the involvement of adults (any person over the age of 18) in the epidemic that is cyber bullying. A comprehensive literature review analysis was created on the current research available on cyber bullying in adolescents and the issues that exist within it. It was found that the majority of the research is still in the understanding of the topic both proactively and re-actively. It has been understood that the absorption of the Internet and the cyber world into the work center has brought the threat of cyber bullying. This research proposal will review literature that discusses what cyber bullying is, what it does to a work environment and why the issue is so serious. The methodology is then mapped out on how this research plans to be carried out. The author plans to review four research questions which are: How prevalent is cyber bullying in today\u27s military? How does cyber bullying affect military members? What forms of cyber bullying affect military members the strongest? And what programs, if any, can be edited or created to combat the threat of cyber bulling in our work force? Content analysis will be used to see what differences exist or fail to exist. The collection method of using academic search engines is outlined in detail

Exciton Regeneration at Polymeric Semiconductor Heterojunctions

Control of the band-edge offsets at heterojunctions between organic semiconductors allows efficient operation of either photovoltaic or light-emitting diodes. We investigate systems where the exciton is marginally stable against charge separation, and show via E-field-dependent time-resolved photoluminescence spectroscopy that excitons that have undergone charge separation at a heterojunction can be efficiently regenerated. This is because the charge transfer produces a geminate electron-hole pair (separation 2.2-3.1nm) which may collapse into an exciplex and then endothermically (E=100-200meV) back-transfer towards the exciton.Comment: 10 pages, 4 figures. Manuscript in press in Phys. Rev. Let

Community Structure in the United States House of Representatives

We investigate the networks of committee and subcommittee assignments in the United States House of Representatives from the 101st--108th Congresses, with the committees connected by ``interlocks'' or common membership. We examine the community structure in these networks using several methods, revealing strong links between certain committees as well as an intrinsic hierarchical structure in the House as a whole. We identify structural changes, including additional hierarchical levels and higher modularity, resulting from the 1994 election, in which the Republican party earned majority status in the House for the first time in more than forty years. We also combine our network approach with analysis of roll call votes using singular value decomposition to uncover correlations between the political and organizational structure of House committees.Comment: 44 pages, 13 figures (some with multiple parts and most in color), 9 tables, to appear in Physica A; new figures and revised discussion (including extra introductory material) for this versio

The geology and petrogenesis of the southern closepet granite

The Archaean Closepet Granite is a polyphase body intruding the Peninsular Gneiss Complex and the associated supracrustal rocks. The granite out-crop runs for nearly 500 km with an approximate width of 20 to 25 km and cut across the regional metamorphic structure passing from granulite facies in the South and green schist facies in the north. In the amphibolite-granulite facies transition zone the granite is intimately mixed with migmatites and charnockite. Field observations suggests that anatexis of Peninsular gneisses led to the formation of granite melt, and there is a space relationship between migmatite formation, charnockite development and production and emplacement of granite magma. Based on texture and cross cutting relationships four major granite phases are recognized: (1) Pyroxene bearing dark grey granite; (2) Porphyritec granite; (3) Equigranular grey granite; and (4) Equigranular pink granite. The granite is medium to coarse grained and exhibit hypidiomorphic granular to porphyritic texture. The modal composition varies from granite granodiorite to quartz monzonite. Geochemical variation of the granite suite is consistent with either fractional crystallization or partial melting, but in both the cases biotite plus feldspar must be involved as fractionating or residual phases during melting to account trace element chemistry. The trace element data has been plotted on discriminant diagrams, where majority of samples plot in volcanic arc and within plate, tectonic environments. The granite show distinct REE patterns with variable total REE content. The REE patterns and overall abundances suggests that the granite suite represents a product of partial melting of crustal source in which fractional crystallization operated in a limited number of cases

Dinitrosyl formation as an intermediate stage of the reduction of NO in the presence of MoO_3

We present first-principles calculations in the framework of density-functional theory and the pseudopotential approach, aiming to model the intermediate stages of the reduction of NO in the presence of MoO$_3$(010). In particular, we study the formation of dinitrosyl, which proves to be an important intermediate stage in the catalytic reduction. We find that the replacement of an oxygen of MoO$_3$ by NO is energetically favorable, and that the system lowers further its energy by the formation of (NO)$_2$. Moreover, the geometry and charge distribution for the adsorbed dinitrosyl indicates a metal-oxide mediated coupling between the two nitrogen and the two oxygen atoms. We discuss the mechanisms for the dinitrosyl formation and the role of the oxide in the reaction.Comment: 6 pages, 4 figs, RevTeX. To be published in J. Chem. Phy