Cryogenic wind tunnels for high Reynolds number testing

A compilation of lectures presented at various Universities over a span of several years is discussed. A central theme of these lectures has been to present the research facility in terms of the service it provides to, and its potential effect on, the entire community, rather than just the research community. This theme is preserved in this paper which deals with the cryogenic transonic wind tunnels at Langley Research Center. Transonic aerodynamics is a focus both because of its crucial role in determining the success of aeronautical systems and because cryogenic wind tunnels are especially applicable to the transonics problem. The paper also provides historical perspective and technical background for cryogenic tunnels, culminating in a brief review of cryogenic wind tunnel projects around the world. An appendix is included to provide up to date information on testing techniques that have been developed for the cryogenic tunnels at Langley Research Center. In order to be as inclusive and as current as possible, the appendix is less formal than the main body of the paper. It is anticipated that this paper will be of particular value to the technical layman who is inquisitive as to the value of, and need for, cryogneic tunnels

Effects of Single versus Multiple Warnings on Driver Performance

Objective: To explore how a single master alarm system affects drivers’ responses when compared to multiple, distinct warnings. Background: Advanced driver warning systems are intended to improve safety, yet inappropriate integration may increase the complexity of driving, especially in high workload situations. This study investigated the effects of auditory alarm scheme, reliability, and collision event-type on driver performance. Method: A 2x2x4 mixed factorial design investigated the impact of two alarm schemes (master vs. individual) and two levels of alarm reliability (high and low) on distracted drivers’ performance across four collision event-types (frontal collision warnings, left and right lane departure warnings, and follow vehicle fast approach). Results: Participants’ reaction times and accuracy rates were significantly affected by the type of collision event and alarm reliability. The use of individual alarms, rather than a single master alarm, did not significantly affect driving performance in terms of reaction time or response accuracy. Conclusion: Even though a master alarm is a relatively uninformative warning, it produced statistically no different reaction times or accuracy results when compared to information-rich auditory icons, some of which were spatially located. In addition, unreliable alarms negatively impacted driver performance, regardless of event type or alarm scheme. Application: These results have important implications for the development and implementation of multiple driver warning systems.This project was sponsored by the Ford Motor Company

QCD corrections to associated t anti-t h production at hadron colliders

We briefly present the status of QCD corrections to the inclusive total cross section for the production of a Higgs boson in association with a top-quark pair within the Standard Model at hadron colliders.Comment: 3 pages, talk given at 31st International Conference on High Energy Physics (ICHEP 2002), Amsterdam, The Netherlands, 24-31 Jul 200

Antibiotic Stewardship Among Primary Care Providers In Mississippi

The World Health Organization states antimicrobial resistance is the ability of a microorganism to stop an antimicrobial from working which results in ineffective treatment and persistent infections. The Center for Disease Control and Prevention (CDC, 2017) reported that in the year 2015, 269.4 million antibiotic prescriptions were written in the outpatient setting, and approximately 30% of antibiotics written are unwarranted. Of those cases, most patients receive an antibiotic related to acute uncomplicated bronchitis, pharyngitis, or rhinosinusitis. The CDC reported that Americans spend nearly $11 billion yearly on antibiotics alone. However, up to 50% of all antibiotics prescribed are not indicated or optimally effective which eventually leads to resistance. Antibiotic resistant infections are associated with loss of productivity, poorer health outcomes, and greater healthcare costs. The CDC launched The Get Smart: Know When Antibiotics Work campaign in 2003 which aimed to direct appropriate antibiotic use (CDC, 2017). Within this campaign, the CDC provides outpatient regarding condition, epidemiology, diagnosis, and management for providers to follow for appropriate prescription. The purpose of this study was to determine if primary care providers in Mississippi are following the CDC Adult Treatment Recommendations for antibiotic use in the treatment of acute uncomplicated bronchitis, streptococcal pharyngitis, and acute unspecified pharyngitis (CDC, 2016). The researchers collected data in six rural clinics across Mississippi. This study consisted of a quantitative, retrospective chart review with descriptive statistics. A convenience sampling of 582 charts were obtained for the retrospective review. For data collection, the researchers used a data collection tool which included information related to age, gender, insurance, title o f provider, and diagnoses related to the current research and CDC Adult Treatment Recommendations. Prior to conducting the study, consent was obtained from the Institutional Review Board (IRB) at the Mississippi University for Women. After data collection, data were subjected to analyses using descriptive statistics including, but not limited to, frequency, distributions, and percentages. The findings suggested that primary care providers in Mississippi are not consistently following the CDC Adult Treatment Recommendations for acute pharyngitis and uncomplicated bronchitis

Snowmass 2001: Jet Energy Flow Project

Conventional cone jet algorithms arose from heuristic considerations of LO hard scattering coupled to independent showering. These algorithms implicitly assume that the final states of individual events can be mapped onto a unique set of jets that are in turn associated with a unique set of underlying hard scattering partons. Thus each final state hadron is assigned to a unique underlying parton. The Jet Energy Flow (JEF) analysis described here does not make such assumptions. The final states of individual events are instead described in terms of flow distributions of hadronic energy. Quantities of physical interest are constructed from the energy flow distribution summed over all events. The resulting analysis is less sensitive to higher order perturbative corrections and the impact of showering and hadronization than the standard cone algorithms.Comment: REVTeX4, 13 pages, 6 figures; Contribution to the P5 Working Group on QCD and Strong Interactions at Snowmass 200

Three-jet cross sections in hadron-hadron collisions at next-to-leading order

We present a new QCD event generator for hadron collider which can calculate one-, two- and three-jet cross sections at next-to-leading order accuracy. In this letter we study the transverse energy spectrum of three-jet hadronic events using the kT algorithm. We show that the next-to-leading order correction significantly reduces the renormalization and factorization scale dependence of the three-jet cross section.Comment: 4 pages, 4 figures, REVTEX

Water and Metasomatism in the Slave Cratonic Lithosphere (Canada): An FTIR Study

Water in the mantle influences melting, viscosity, seismic velocity, and electrical conductivity. The role played by water in the long-term stabilization of cratonic roots is currently being debated. This study focuses on water contents of mantle minerals (olivine, pyroxene and garnet) from xenoliths found in kimberlites of the Archean Slave craton. 19 mantle xenoliths from central Lac de Gras, and 10 from northern Jericho were analyzed by FTIR for water, and their equilibration depths span the several compositional layers identified beneath the region. At both locations, the shallow peridotites have lower water contents in their olivines (11-30 ppm H2O) than those from the deeper layers (28-300 ppm H2O). The driest olivines, however, are not at the base of the cratonic lithosphere (>6 GPa) as in the Kaapvaal craton. Instead, the deepest olivines are hydrous (31-72 ppm H2O at Lac de Gras and 275 ppm H2O at Jericho). Correlations of water in clinopyroxene and garnet with their other trace element contents are consistent with water being added by metasomatism by melts resembling kimberlite precursors in the mantle approx.0.35 Ga ago beneath Lac de Gras. The northern Jericho xenoliths are derived from a region of the Slave craton that is even more chemically stratified, and was affected at depth by the 1.27 Ga Mackenzie igneous events. Metasomatism at Jericho may be responsible for the particularly high olivine water contents (up to 300 ppm H2O) compared to those at Lac de Gras, which will be investigated by acquiring trace-element data on these xenoliths. These data indicate that several episodes of metasomatic rehydration occurred in the deep part of the Slave craton mantle lithosphere, with the process being more intense in the northern part beneath Jericho, likely related to a translithospheric suture serving as a channel to introduce fluids and/or melts in the northern region. Consequently, rehydration of the lithosphere does not necessarily cause cratonic root delamination and these peridotites may represent localized metasomatic zones - the wall rocks to kimberlite magma passage

Summary: Working Group on QCD and Strong Interactions

In this summary of the considerations of the QCD working group at Snowmass 2001, the roles of quantum chromodynamics in the Standard Model and in the search for new physics are reviewed, with empahsis on frontier areas in the field. We discuss the importance of, and prospects for, precision QCD in perturbative and lattice calculations. We describe new ideas in the analysis of parton distribution functions and jet structure, and review progress in small-$x$ and in polarization.Comment: Snowmass 2001. Revtex4, 34 pages, 4 figures, revised to include additional references on jets and lattice QC

Applications of QCD

Talk given at XIXth International Symposium on Lepton and Photon Interactions at High Energies (LP 99), Stanford, California, 9-14 August 1999.Comment: latex, 26 page