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Wind-Tunnel Investigation of Effects of Unsymmetrical Horizontal-Tail Arrangements on Power-on Static Longitudinal Stability of a Single-Engine Airplane Model

Description: Report presenting a wind-tunnel investigation to determine the effects of unsymmetrical horizontal-tail arrangements on the power-on static longitudinal stability of a single-engine single-rotation airplane. Extreme asymmetry in the horizontal tail was found to cause issues with the longitudinal stability, but the "practical" arrangement tested did not show much improvement. Results regarding the longitudinal stability tests, computations, and lateral and directional trim are provided.
Date: October 1947
Creator: Purser, Paul E. & Spear, Margaret F.
Partner: UNT Libraries Government Documents Department

Examining the Role of Latitude and Differential Insolation in Asymmetrical Valley Development

Description: Valley development through erosional processes typically tends to create symmetrical valleys. Over time, water cuts through the substrate to create valleys, gorges, and canyons for which the sides are the valley are evenly sloped. However, there are anomalies to this process. Asymmetrical valleys have been well-documented even in areas of uniform substrate or little tectonic uplift. One proposed explanation for the asymmetry of these valleys is differential insolation. This may lead to different microclimates from one slope to another which alter the rate and extent of erosion. Since the differences in received insolation vary with latitude (especially in streams that flow along an east/west axis), it follows that the degree of asymmetry should also vary with latitude if differential insolation is a primary driving factor in the development of these valleys. To evaluate if insolation plays a role in the development of asymmetrical valleys, this study examines variability in asymmetry across 447 valleys in nine study areas located at different latitudes. The degree of asymmetry for each valley was measured by using 30 meter resolution digital elevation models (DEMs) to determine the slope angle of each side of the valley. Asymmetry was measured by computing a ratio of the average slope angle for each side of the valley (larger value divided by smaller). If the resulting value is one, the valley is deemed symmetrical. As the value increases, the degree of asymmetry increases. This investigation found that contrary to expectations, valleys at lower latitudes tend to have a higher degree of asymmetry than those at higher latitudes, which suggests that differential insolation does not play a major role in the development of these valleys. Instead, this study found that high altitudes and low latitudes are more frequently associated with a higher degree of asymmetry. These unexpected findings open the door ...
Date: August 2013
Creator: Curran, Lorna L.
Partner: UNT Libraries

Azimuthal and single spin asymmetry in deep-inelasticlepton-nucleon scattering

Description: The collinear expansion technique is generalized to thefactorization of unintegrated parton distributions and other higher twistparton correlations from the corresponding collinear hard parts thatinvolve multiple parton final state interaction. Such a generalizedfactorization provides a consistent approach to the calculation ofinclusive and semi-inclusive cross sections of deep-inelasticlepton-nucleon scattering. As an example, the azimuthal asymmetry iscalculated to the order of 1/Q in semi-inclusive deeply inelasticlepton-nucleon scattering with transversely polarized target. Anon-vanishing single-spin asymmetry in the "triggered inclusive process"is predicted to be 1/Q suppressed with a part of the coefficient relatedto a moment of the Sivers function.
Date: September 21, 2006
Creator: Liang, Zuo-tang & Wang, Xin-Nian
Partner: UNT Libraries Government Documents Department

Unvail the Mysterious of the Single Spin Asymmetry

Description: Single transverse-spin asymmetry in high energy hadronic reaction has been greatly investigated from both experiment and theory sides in the last few years. In this talk, I will summarize some recent theoretical developments, which, in my opinion, help to unvail the mysterious of the single spin asymmetry.
Date: January 5, 2010
Creator: Yuan, Feng
Partner: UNT Libraries Government Documents Department

Flow Tones in a Pipeline-Cavity System: Effect of Pipe Asymmetry

Description: Flow tones in a pipeline-cavity system are characterized in terms of unsteady pressure within the cavity and along the pipe. The reference case corresponds to equal lengths of pipe connected to the inlet and outlet ends of the cavity. Varying degrees of asymmetry of this pipe arrangement are investigated. The asymmetry is achieved by an extension of variable length, which is added to the pipe at the cavity outlet. An extension length as small as a few percent of the acoustic wavelength of the resonant mode can yield a substantial reduction in the pressure amplitude of the flow tone. This amplitude decrease occurs in a similar fashion within both the cavity and the pipe resonator, which indicates that it is a global phenomenon. Furthermore, the decrease of pressure amplitude is closely correlated with a decrease of the Q (quality)-factor of the predominant spectral component of pressure. At a sufficiently large value of extension length, however, the overall form of the pressure spectrum recovers to the form that exists at zero length of the extension. Further insight is provided by variation of the inflow velocity at selected values of extension length. Irrespective of its value, both the magnitude and frequency of the peak pressure exhibit a sequence of resonant-like states. Moreover, the maximum attainable magnitude of the peak pressure decreases with increasing extension length.
Date: May 29, 2002
Creator: Erdem, D.; rockwell, D.; Oshkai, P. & Pollack, M.
Partner: UNT Libraries Government Documents Department

Flow Tones in a Pipeline-Cavity System: Effect of Pipe Asymmetry

Description: Flow tones in a pipeline-cavity system are characterized in terms of unsteady pressure within the cavity and along the pipe. The reference case corresponds to equal lengths of pipe connected to the inlet and outlet ends of the cavity. Varying degrees of asymmetry of this pipe arrangement are investigated. The asymmetry is achieved by an extension of variable length, which is added to the pipe at the cavity outlet. An extension length as small as a few percent of the acoustic wavelength of the resonant mode can yield a substantial reduction in the pressure amplitude of the flow tone. This amplitude decrease occurs in a similar fashion within both the cavity and the pipe resonator, which indicates that it is a global phenomenon. Furthermore, the decrease of pressure amplitude is closely correlated with a decrease of the Q (quality)-factor of the predominant spectral component of pressure. At a sufficiently large value of extension length, however, the overall form of the pressure spectrum recovers to the form that exists at zero length of the extension. Further insight is provided by variation of the inflow velocity at selected values of extension length. Irrespective of its value, both the magnitude and frequency of the peak pressure exhibit a sequence of resonant-like states. moreover, the maximum attainable magnitude of the peak pressure decreases with increasing extension length.
Date: February 28, 2001
Creator: Erdem, D.; Rockwell, D.; Oshkai, P.L. & Pollack, M.
Partner: UNT Libraries Government Documents Department

On the Relation Between Mechanisms for Single-Transverse-SpinAsymmetries

Description: Recent studies have shown that two widely-used mechanismsfor single-transverse-spin asymmetries based on either twist-threecontributions or on transverse-momentum-dependent (Sivers) partondistributions become identical in a kinematical regime of overlap. Thiswas demonstrated for the so-called soft-gluon-pole and hard-polecontributions to the asymmetry associated with a particular quark-gluoncorrelation function in the nucleon. In this paper, using semi-inclusivedeep inelastic scattering as an example, we extend the study to thecontributions by soft-fermion poles and by another independenttwist-three correlation function. We find that these additional termsorganize themselves in such a way as to maintain the mutual consistencyof the two mechanisms for single-spin asymmetries.
Date: November 5, 2007
Creator: Koike, Yuji; Vogelsang, Werner & Yuan, Feng
Partner: UNT Libraries Government Documents Department

Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks

Description: Emission factors for black carbon (BC) and particle number (PN) were measured from 226 individual heavy-duty (HD) diesel-fueled trucks driving through a 1 km-long California highway tunnel in August 2006. Emission factors were based on concurrent increases in BC, PN, and CO{sub 2}B concentrations (measured at 1 Hz) that corresponded to the passage of individual HD trucks. The distributions of BC and PN emission factors from individual HD trucks are skewed, meaning that a large fraction of pollution comes from a small fraction of the in-use vehicle fleet. The highest-emitting 10% of trucks were responsible for {approx} 40% of total BC and PN emissions from all HD trucks. BC emissions were log-normally distributed with a mean emission factor of 1.7 g kg {sup -1} and maximum values of {approx} 10 g kg{sup -1}. Corresponding values for PN emission factors were 4.7 x 10{sup 15} and 4 x 10{sup 16} kg{sup -1}. There was minimal overlap among high-emitters of these two pollutants: only 1 of the 226 HD trucks measured was found to be among the highest 10% for both BC and PN. Monte Carlo resampling of the distribution of BC emission factors observed in this study revealed that uncertainties (1{sigma}) in extrapolating from a random sample of n HD trucks to a population mean emission factor ranged from {+-} 43% for n = 10 to {+-} 8% for n = 300, illustrating the importance of sufficiently large vehicle sample sizes in emissions studies. Studies with low sample sizes are also more easily biased due to misrepresentation of high-emitters. As vehicles become cleaner on average in future years, skewness of the emissions distributions will increase, and thus sample sizes needed to extrapolate reliably from a subset of vehicles to the entire in-use vehicle fleet are expected to become more of a ...
Date: February 2, 2009
Creator: Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W. & Harley, Robert A.
Partner: UNT Libraries Government Documents Department

Exposing the non-collectivity in elliptic flow

Description: We show that backward-forward elliptic asymmetry correlations provide an experimentally accessible observable which distinguishes between collective and non-collective contributions to the observed elliptic asymmetry v2 in relativistic heavy ion collisions. The measurement of this observable will reveal the momentum scale at which collective expansion seizes and where the elliptic asymmetry is dominated by (semi)-hard processes. In addition, the knowledge of the actual magnitude of the collective component of the elliptic asymmetry will be essential for the extraction of the viscosity of the matter created in these collisions.
Date: February 13, 2009
Creator: Liao, Jinfeng & Koch, Volker
Partner: UNT Libraries Government Documents Department

Longitudinal double-spin asymmetry for inclusive jet production in vec p + vec p collisions at sqrt s = 200 GeV

Description: We report a new STAR measurement of the longitudinal double-spin asymmetry A{sub LL} for inclusive jet production at mid-rapidity in polarized p + p collisions at a center-of-mass energy of {radical}s = 200 GeV. The data, which cover jet transverse momenta 5 < p{sub T} < 30 GeV/c, are substantially more precise than previous measurements. They provide significant new constraints on the gluon spin contribution to the nucleon spin through the comparison to predictions derived from one global fit of polarized deep-inelastic scattering measurements.
Date: October 7, 2007
Creator: Coll, STAR
Partner: UNT Libraries Government Documents Department

Hyperon production asymmetries in 500 GeV/c pion nucleus Interactions

Description: We present a preliminary study from Fermilab experiment E791 of {Lambda}{sup 0}/{anti {Lambda}}{sup 0}, {Xi}{sup -}/{Xi}{sup +} and {Omega}{sup -}/{Omega}{sup +} production asymmetries from {pi}{sup -} nucleus interactions at 500 Gev/c. The production asymmetries for these particles are studied as a function of x{sub F} and p{sup 2}{sub T}. We observed an asymmetry in the target fragmentation region for {Lambda}{sup 0}`s larger than that for {Xi}`s, suggesting diquark effects. The asymmetry for {Omega}`s is significatively smaller than for the other two hyperons consistent with the fact that {Omega}`s do not share valence quarks with either the pion or the target particle. In the beam fragmentation region, the asymmetry tends to 0.1 for both {Lambda}{sup 0}`s and {Xi}`s. The asymmetries vs p{sup 2}{sub T} are approximately constant for the three strange baryons under study.
Date: October 1, 1997
Creator: Solano, J.; Magnin, J.; Simao, F.R.A. & Collaboration, E791
Partner: UNT Libraries Government Documents Department

Polarization Asymmetries in gamma e Collisions and Triple Gauge Boson Couplings Revisited

Description: The capability of the NLC run in the {gamma}e collision mode to probe the CP-conserving {gamma}WW and {gamma}ZZ anomalous couplings through the use of the polarization asymmetry is reviewed. When combined with other measurements, very strong constraints on both varieties of anomalous couplings can be obtained. We show that these bounds are complementary to those that can be extracted from data taken at the LHC.
Date: July 16, 1999
Creator: Rizzo, Thomas G.
Partner: UNT Libraries Government Documents Department

Asymmetrical polarization of spherical colloidal particle double layer in electrical fields

Description: It has long been accepted that the drastic increase in the viscosity of electrorheological fluids subjected to electric fields is due to interactions between the induced dipole moments of the colloidal particles in the suspensions. Computer simulations of dipole-dipole interactions have produced chain and column formations of particles in the direction of the applied field that agree well with experimental observations. In an aqueous suspension of colloidal particles, however, the polarization of particles is very sensitive to the frequency of the applied electric field, and the dynamics of the particles can differ drastically from the dynamics that would be expected from a simple induced dipole model. In certain frequency regimes, instead of forming chains and columns in the direction of a linear applied field, the particles are dynamically unstable and circulate in bands that tilt at a significant angle relative to the direction of the field. This indicates that the interactions between the particles are no longer symmetrical with respect to the applied electric field. The authors have proposed a phenomenological model to explain the mechanism of this symmetry breaking. They have carried out a computer simulation of colloidal particle dynamics resulting from their model, and the results of the simulation agree well with experimental observations. When a particle is spinning, the diffusion of the ions in the double layer becomes asymmetrical with respect to the electric field, with the ions diffusing faster in the direction of spinning than against it. This causes the induced dipole moment of the particle to be misaligned with respect to the applied field. The authors earlier simulation results show that this misalignment between the polarization of the particle and the applied electric field plays a crucial role in the formation of a band of particles tilted at an angle relative to the direction of ...
Date: April 1, 1995
Creator: Hu, Y.; Kumar, V. & Fraden, S.
Partner: UNT Libraries Government Documents Department

Measurement of the cp asymmetry Parameter sin(2{beta}) at CDF

Description: We present a measurement of the time-dependent asymmetry in the rate for {anti }B{sup 0}{sub d} versus B{sup 0}{sub d} decays to J/{psi} K{sup 0}{sub S} . In the context of the Standard Model this is interpreted as a measurement of the CP-violation parameter sin(2{beta}). A total of 198 {+-} 17 B{sup 0}{sub d}/{anti B}{sup 0}{sub d} decays were observed in p{anti p} collisions at ps = 1:8 TeV by the CDF detector at the Fermilab Tevatron. The initial b-flavor is determined by a same side avor tagging technique. Our analysis results in sin(2{beta}) = 1:8 {+-} 1:1(stat) {+-} 0:3(syst).
Date: October 1, 1998
Creator: LeCompte, T. J.
Partner: UNT Libraries Government Documents Department

Background Enhancement of CPT Reach at an Asymmetric Phi Factory

Description: Photoproduction of neutral-kaon pairs is studied from the perspective of CP and CPT studies. Interference of the P and S waves, with the former due to diffractive phi production and the latter to f{_}0/a{_}0 production, is shown to enhance the CPT reach. Results are presented of Monte Carlo studies based on rates expected in future experiments.
Date: June 1, 2001
Creator: Isgur, Nathan; Kostelecky, Alan & Szczepaniak, Adam
Partner: UNT Libraries Government Documents Department

Baryogenesis and low energy CP violation

Description: CP violation is a crucial component in the creation of the matter - anti matter asymmetry of the universe. An important open question is whether the CP violating phenomena observeable in terrestrial experiments have any relation with those responsible for baryogenesis. We discuss two mechanisms of baryogenesis where this question can be meaningfully posed: ''electroweak baryogenesis'' and ''baryogenesis via leptogenesis''. We show how these scenarios can be constrained by existing and forthcoming experimental data. We present a specific example of both these scenarios where the CP violating phase in the Cabbibo Kobayashi Maskawa matrix is related in a calculable way to the CP violating phase responsible for baryogenesis.
Date: August 19, 1999
Creator: Worah, Mihir P.
Partner: UNT Libraries Government Documents Department

Automaticity and Hemispheric Specialization in Emotional Expression Recognition: Examined using a modified Stroop Task

Description: The main focus of this investigation was to examine the automaticity of facial expression recognition through valence judgments in a modified photo-word Stroop paradigm. Positive and negative words were superimposed across male and female faces expressing positive (happy) and negative (angry, sad) emotions. Subjects categorized the valence of each stimulus. Gender biases in judgments of expressions (better recognition for male angry and female sad expressions) and the valence hypothesis of hemispheric advantages for emotions (left hemisphere: positive; right hemisphere: negative) were also examined. Four major findings emerged. First, the valence of expressions was processed automatically (robust interference effects). Second, male faces interfered with processing the valence of words. Third, no posers' gender biases were indicated. Finally, the emotionality of facial expressions and words was processed similarly by both hemispheres.
Date: August 2002
Creator: Beall, Paula M.
Partner: UNT Libraries

Run-09 pC polarimeter analysis

Description: Analysis of PC polarimeter data at {radical}s = 200 and 500 GeV from Run9 is presented. Final polarization results, fill-by-fill, for blue and yellow beams, as to be used by RHIC experiments (in collisions) are released and collected in http://www4.rcf.bnl.gov/cnipol/pubdocs/Run09Offline/. Global relative systematic uncertainties {delta}P/P (to be considered as correlated from fill to fill) are 4.7% for 100 GeV beams, and 8.3% (12.1%) for blue (yellow) 250 GeV beams. For a product of two beam polarizations P{sub B} {center_dot} P{sub Y} (used in double spin asymmetry measurements) the relative uncertainty {delta}(P{sub B} {center_dot} P{sub Y})/(P{sub B} {center_dot} P{sub Y}) 8.8% for 100 GeV beams and 18.5% for 250 GeV beams. For the average between two beam polarization (P{sub B} + P{sub Y})/2 (used in single spin asymmetry measurements, when data from two polarized beams are combined) the relative uncertainty is 4.4% for 100 GeV beams and 9.2% for 250 GeV beams. Larger uncertainties for 250 GeV beams relate to significant rate related systematic effects experienced in the first part of Run9 (due to thicker targets used and smaller trans. beam size at higher beam energy).
Date: August 1, 2010
Creator: Alekseev, I.; Aschenauer, E.; Atoyan, G.; Bazilevsky, A.; Gill, R.; Huang, H. et al.
Partner: UNT Libraries Government Documents Department

Laboratory experiments on dispersive transport across interfaces: The role of flow direction

Description: We present experimental evidence of asymmetrical dispersive transport of a conservative tracer across interfaces between different porous materials. Breakthrough curves are measured for tracer pulses that migrate in a steady state flow field through a column that contains adjacent segments of coarse and fine porous media. The breakthrough curves show significant differences in behavior, with tracers migrating from fine medium to coarse medium arriving significantly faster than those from coarse medium to fine medium. As the flow rate increases, the differences between the breakthrough curves diminish. We argue that this behavior indicates the occurrence of significant, time-dependent tracer accumulation in the resident concentration profile across the heterogeneity interface. Conventional modeling using the advection-dispersion equation is demonstrated to be unable to capture this asymmetric behavior. However, tracer accumulation at the interface has been observed in particle-tracking simulations, which may be related to the asymmetry in the observed breakthrough curves.
Date: April 1, 2009
Creator: Berkowitz, B.; Cortis, A.; Dror, I. & Scher, H.
Partner: UNT Libraries Government Documents Department

Density distribution for a polymer absorbed at an oil-waterinterface

Description: The interaction between a polymer segment and an oil-water interface is represented by an asymmetric square-well potential where the well-depth on one side reflects water-polymer and the well depth on the other side reflects oil-polymer interactions. The polymer is represented by a Gaussian chain. The polymer's density distribution is calculated along a coordinate perpendicular to the interface. Results are obtained as a function of the well width, the well depth and its asymmetry and, most important, the polymer's length. For a symmetric well, the distribution shows a strong maximum at the interface provided that the polymer is sufficiently long. For an asymmetric well, the polymer is also strongly adsorbed at the interface provided that the polymer is sufficiently long and provided that the larger well-depth does not exceed a critical value that depends on the smaller well-depth. The calculations are in substantial agreement with experimental results that indicate nearly irreversible adsorption of long-chain molecules at an oil-water interface.
Date: October 30, 2002
Creator: Cai, Jun & Prausnitz, John M.
Partner: UNT Libraries Government Documents Department

Universality and mX cut effects in B ->Xsl+l-

Description: The most precise comparison between theory and experiment for the B {yields} X{sub s}{ell}{sup +}{ell}{sup -} rate is in the q{sup 2} < 6 GeV{sup 2} region. The hadronic uncertainties associated with an experimentally required cut on m{sub X} potentially spoil the extraction of short distance flavor-changing neutral current couplings. We compute the m{sub X} cut dependence of d{Lambda}(B {yields} X{sub s}{ell}{sup +}{ell}{sup -})/dq{sup 2} using the B {yields} X{sub s}{gamma} shape function, and show that the effect is universal for all short distance contributions in the limit m{sub X}{sup 2} << m{sub B}{sup 2}. This universality is not spoiled by realistic values of the m{sub X} cut, nor by {alpha}{sub s} corrections. Alternatively, normalizing the B {yields} X{sub s}{ell}{sup +}{ell}{sup -} rate to B {yields} X{sub u}{ell}{bar {nu}} with the same cuts removes the main uncertainties. We find that the forward-backward asymmetry vanishes near q{sub 0}{sup 2} = 3 GeV{sup 2}.
Date: December 15, 2005
Creator: Lee, Keith S.M.; Ligeti, Zoltan; Stewart, Iain W. & Tackmann,Frank J.
Partner: UNT Libraries Government Documents Department