40,909 research outputs found
Coulomb gauge confinement in the heavy quark limit
The relationship between the nonperturbative Green's functions of Yang-Mills
theory and the confinement potential is investigated. By rewriting the
generating functional of quantum chromodynamics in terms of a heavy quark mass
expansion in Coulomb gauge, restricting to leading order in this expansion and
considering only the two-point functions of the Yang-Mills sector, the
rainbow-ladder approximation to the gap and Bethe-Salpeter equations is shown
to be exact in this case and an analytic, nonperturbative solution is
presented. It is found that there is a direct connection between the string
tension and the temporal gluon propagator. Further, it is shown that for the
4-point quark correlation functions, only confined bound states of
color-singlet quark-antiquark (meson) and quark-quark (baryon) pairs exist.Comment: 22 pages, 6 figure
The Effects of Blowing Over Various Trailing-edge Flaps on an NACA 0006 Airfoil Section, Comparisons with Various Types of Flaps on other Airfoil Sections, and an Analysis of Flow and Power Relationships for Blowing Systems
The results are presented of a two-dimensional investigation conducted to determine the effect of blowing over various types of trailing-edge flaps on a wing having the NACA 0006 airfoil section and a drooped-nose flap. The position and profile of the trailing-edge flap, the nozzle height, and the location of the flap with respect to the nozzle were found to be important variables. Data from many investigations were used to make an evaluation of the effects of blowing on lift. An analysis was made of flow and power relationships for blowing systems
Effect of Reynolds number on stability characteristics of a cruciform wing-body
An experimental investigation was conducted to determine the effect of Reynolds number on the stability characteristics of a body with cruciform wings at large angles of attack. Pressure distributions and force and moment data (axial force not measured) are presented for Mach 1.60 and 2.70, Reynolds numbers based on body diameter from approximately 130,000 to 2,800,000, and angles of attack from 0 deg to 50 deg. In general, the data show only small effects of Reynolds number throughout the range of test condition. Also discussed are force balance and pressure data that suggest a direct relationship between wind choking and the onset of a nonlinear stability variaton with angle of attack
Baker Street Wonderpass: evaluation of improvement works
Summary:
Baker Street Quarter Partnership identified the pedestrian subway under the Marylebone Road as an area that many of its members would like to see improved. Researchers from the Policy Studies Institute were commissioned to provide an impartial evaluation of improvement works that were carried out to transform the subway into the ‘Baker Street Wonderpass’.
The views of users were assessed through an online survey of Baker Street Quarter members (June 2015), pedestrian counting and face-to-face surveys both before the improvement works (July 2015) and after the Wonderpass had opened (February 2016). The pre-works surveys took place in July 2015, with 206 subway users’ answering a total of 12 questions. The post-works surveys took place in February 2016 with 163
subway users answering a total of 15 questions. The survey was supplemented by ‘vox-pop’ interviews.
Pedestrian counts before and after the improvement works show a very large increase in pedestrian traffic after the improvement works were completed. After the improvement works, morning usage increased by 153.8%, afternoon usage increasing by 27.8%, and evening usage increasing by 70.8%.
Survey results showed a substantial improvement in user’s satisfaction with the lighting, cleanliness, overall appearance, safety, signage and visibility of the subway. The redevelopment of the subway and the opening of the Wonderpass have been a clear success. 83.9% of users said that the subway was ‘much better’, and 98.4% of users said that they thought the subway was ‘better’ or ‘much better’ after the improvement works.
Overall, the investment in the Marylebone Road underpass has greatly improved usage levels and user perceptions of the subway and some users stated that they used the subway solely to see the renovations and new displays. While users previously complained about the cleanliness, lighting and appearance of the subway, by February 2016 it has been successfully transformed into a much safer, cleaner, and more desirable ‘Wonderpass’ to cross Marylebon
Freezing line of the Lennard-Jones fluid: a Phase Switch Monte Carlo study
We report a Phase Switch Monte Carlo (PSMC) method study of the freezing line
of the Lennard-Jones (LJ) fluid. Our work generalizes to soft potentials the
original application of the method to hard sphere freezing, and builds on a
previous PSMC study of the LJ system by Errington (J. Chem. Phys. {\bf 120},
3130 (2004)). The latter work is extended by tracing a large section of the
Lennard-Jones freezing curve, the results for which we compare to a previous
Gibbs-Duhem integration study. Additionally we provide new background regarding
the statistical mechanical basis of the PSMC method and extensive
implementation details.Comment: 18 pages, 6 figure
Survey of J=0,1 mesons in a Bethe-Salpeter approach
The Bethe-Salpeter equation is used to comprehensively study mesons with
J=0,1 and equal-mass constituents for quark masses from the chiral limit to the
b-quark mass. The survey contains masses of the ground states in all
corresponding J^{PC} channels including those with "exotic" quantum numbers.
The emphasis is put on each particular state's sensitivity to the low- and
intermediate-momentum, i.e., long-range part of the strong interaction.Comment: 8 pages, 4 figure
Counseling College Student-Athletes: A Working Alliance Model Approach
Student-athletes often represent a highly visible, yet decidedly misunderstood population on college and university campuses. In the general student population, the combination of multiple stressors often leads students to seek professional counseling services. Unfortunately, student-athletes, who are often faced with a multitude of psychosocial stressors germane to balancing athletic and academic responsibilities, seldom seek out professional counseling services. However, when they do seek services, the authors posited that an understanding of the construct of the therapeutic working alliance and the application of the working alliance model (Bordin, 1979) offered a useful template for fostering positive counseling outcomes with student-athletes. In this article, the major elements of this construct and model were presented along with a discussion and implications for its application to a college or university student-athlete population
Siderophile Element Profile Measurements in Iron Meteorites Using Laser Ablation ICP-MS
Understanding the behaviour of siderophile elements during cooling of iron meteorites can lead to insight into the general thermal histories of the meteorites as well as their respective parent bodies. Traditionally trace element analyses in meteorites have been done using techniques that only measure the average concentration in each phase. With these methods, all of the spatial information with respect to the distribution of an element within one phase is lost. Measuring concentration profiles of trace elements in meteorites is now possible, with the advent of high-resolution analytical techniques such as laser ablation, inductively coupled plasma mass spectrometry (LA-ICP-MS) with spatial resolution <20 microns. [e.g. 1,2] and secondary ion mass spectrometry [3]. These profiles can give more insight into both the partitioning and diffusive behavior of siderophile elements in metal systems relevant to iron meteorites, as well as parent body cooling rates
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