Turbulence characteristics of an axisymmetric reacting flow

Turbulent sudden expansion flows are of significant theoretical and practical importance. Such flows have been the subject of extensive analytical and experimental study for decades, but many issues are still unresolved. Detailed information on reacting sudden expansion flows is very limited, since suitable measurement techniques have only been available in recent years. The present study of reacting flow in an axisymmetric sudden expansion was initiated under NASA support in December 1983. It is an extension of a reacting flow program which has been carried out with Air Force support under Contract F33615-81-K-2003. Since the present effort has just begun, results are not yet available. Therefore a brief overview of results from the Air Force program will be presented to indicate the basis for the work to be carried out

Computer simulation model of terminal air traffic and PWI systems, phase 1

Collision avoidance computer simulation model of terminal air traffic and proximity warning indicator system

Beta decay of rb86

Measuring of rubidium 86 beta decay using lithium drifted surface barrier silicon detector

Projective-symmetric spaces

Cartanian symmetrical property of Riemannian projective-symmetric spaces - tensor geometr

Study of the concept of inertially aided barometric altimetry system for supersonic aircraft

Study of concept of inertially aided barometric altimetry system to meet vertical separation requirements of 1000 and 2000 feet for Mach 3.5 aircraft in altitude hold at 80,000 fee

Laser cooling in the Penning trap: an analytical model for cooling rates in the presence of an axializing field

Ions stored in Penning traps may have useful applications in the field of quantum information processing. There are, however, difficulties associated with the laser cooling of one of the radial motions of ions in these traps, namely the magnetron motion. The application of a small radio-frequency quadrupolar electric potential resonant with the sum of the two radial motional frequencies has been shown to couple these motions and to lead to more efficient laser cooling. We present an analytical model that enables us to determine laser cooling rates in the presence of such an 'axializing' field. It is found that this field leads to an averaging of the laser cooling rates for the two motions and hence improves the overall laser cooling efficiency. The model also predicts shifts in the motional frequencies due to the axializing field that are in qualitative agreement with those measured in recent experiments. It is possible to determine laser cooling rates experimentally by studying the phase response of the cooled ions to a near resonant excitation field. Using the model developed in this paper, we study the expected phase response when an axializing field is present.Comment: 22 pages, 7 figure

Support for Instructional Leadership: Supervision, Mentoring, and Professional Development for U.S. School Leaders - Findings from the American School Leader Panel

With school leadership second only to teaching among school-related influences on student learning, principals can play an important role in school success. But how do their districts promote their effectiveness, especially in improving teaching? Based on a survey of the American School Leader Panel, a representative sample of principals from across the United States, this report explores the prevalence and quality of three important on-the-job supports for school leaders: supervision, mentorship and professional development (as defined by at least a day focused on principals). The good news is that two-thirds of principals report receiving some support. The bad news is that more than two thirds (68 percent) report that they don't receive all three sources of help. Mentoring, for example, is typically available only to first- or second-year principals or those encountering difficulties on the job, and only a minority of principals report that their districts require mentoring, even for first-year (49 percent of respondents) or struggling principals (21 percent). Also, the prevalence of support a principal receives may depend on the size of his or her school district. Both mentoring and professional development are more readily available in larger and medium-sized districts than smaller ones. The value principals place on the support they receive is linked to whether the support emphasizes the key aspect of principals' job—improving teachers' instruction. For example, all of the principals (100 percent) who reported that their mentors focused on instruction to a great extent also said that they prized the mentoring. That compares with a minority (40 percent) of principals who said their mentors devoted little to no time to instruction

Fixed point scenario in the Two Higgs Doublet Model inspired by degenerate vacua

We consider the renormalisation group flow of Higgs and Yukawa couplings within the simplest non--supersymmetric two Higgs doublet extension of the Standard Model (SM). In this model the couplings are adjusted so that the multiple point principle (MPP) assumption, which implies the existence of a large set of degenerate vacua at some high energy scale $\Lambda$, is realised. When the top quark Yukawa coupling at the scale $\Lambda$ is large, the solutions of RG equations in this MPP inspired 2 Higgs Doublet Model (2HDM) converge to quasi--fixed points. We analyse the Higgs spectrum and couplings in the quasi--fixed point scenario and compute a theoretical upper bound on the lightest Higgs boson mass. When the scale $\Lambda$ is low, the coupling of the SM--like Higgs scalar to the top quark can be significantly larger in the considered model than in the SM, resulting in the enhanced production of Higgs bosons at the LHC.Comment: 16 pages, 3 figures, CERN preprint number added, references update

Nonlinear spectroscopy in the strong-coupling regime of cavity QED

A nonlinear spectroscopic investigation of a strongly coupled atom-cavity system is presented. A two-field pump-probe experiment is employed to study nonlinear structure as the average number of intracavity atoms is varied from N̅≈4.2 to N̅≈0.8. Nonlinear effects are observed for as few as 0.1 intracavity pump photons. A detailed semiclassical simulation of the atomic beam experiment gives reasonable agreement with the data for N̅≳2 atoms. The simulation procedure accounts for fluctuations in atom-field coupling which have important effects on both the linear and nonlinear probe transmission spectra. A discrepancy between the simulations and the experiments is observed for small numbers of atoms (N̅≲1). Unfortunately, it is difficult to determine if this discrepancy is a definitive consequence of the quantum nature of the atom-cavity coupling or a result of the severe technical complications of the experiment

Spin-axis attitude estimation and magnetometer bias determination for the AMPTE mission

Algorithms were developed for magnetometer biases and spin axis attitude calculation. Numerical examples of the performance of the algorithm are given