The Double-Lined Spectroscopic Binary Haro 1-14c

We report detection of the low-mass secondary in the spectroscopic binary Haro 1-14c in the Ophiuchus star forming region. The secondary/primary mass ratio is $0.310\pm 0.014$. With an estimated photometric primary mass of 1.2 $M_{\odot}$, the secondary mass is $\sim 0.4 M_{\odot}$ and the projected semi-major axis is $\sim 1.5$ AU. The system is well-suited for astrometric mapping of its orbit with the current generation of ground-based IR interferometers. This could yield precision values of the system's component masses and distance.Comment: Accepted by ApJ Letter

Mapping a star with transits: orbit precession effects in the Kepler-13 system

Kepler-13b (KOI-13.01) is a most intriguing exoplanet system due to the rapid precession rate, exhibiting several exotic phenomena. We analyzed $Kepler$ Short Cadence data up to Quarter 14, with a total time-span of 928 days, to reveal changes in transit duration, depth, asymmetry, and identify the possible signals of stellar rotation and low-level activity. We investigated long-term variations of transit light curves, testing for duration, peak depth and asymmetry. We also performed cluster analysis on $Kepler$ quarters. We computed the autocorrelation function of the out-of-transit light variations. Transit duration, peak depth, and asymmetry evolve slowly, due to the slowly drifting transit path through the stellar disk. The detected transit shapes will map the stellar surface on the time scale of decades. We found a very significant clustering pattern with 3-orbit period. Its source is very probably the rotating stellar surface, in the 5:3 spin-orbit resonance reported in a previous study. The autocorrelation function of the out-of-transit light variations, filtered to 25.4 hours and harmonics, shows slow variations and a peak around 300--360 day period, which could be related to the activity cycle of the host star.Comment: 7 pages, 7 figures, accepted in MNRA

Herding Cats: Improving Law School Teaching

What makes a good law teacher? Is excellence in teaching largely a matter of intellectual brilliance, of superior organization and delivery of material, of friendliness and fairness to one\u27s students? Or does it have more to do with style, with stage presence, with the ability to engage an audience in the act of reflective and spontaneous thinking? While the question of how to define and evaluate teaching necessarily bedevils deans and tenure committees who must make personnel decisions, the focus on defining the competent teacher has obscured from faculty attention the more fundamental question: how can we implement a system to improve faculty performance across the board? It is this question that law schools around the country have not adequately addressed. Three years ago, the faculty of Franklin Pierce Law Center adopted a program to improve our classroom teaching. This article describes and evaluates that program, in which all three authors played a role

Flow visualization study of the effect of injection hole geometry on an inclined jet in crossflow

A flow visualization was studied by using neutrally buoyant, helium-filled soap bubbles, to determine the effect of injection hole geometry on the trajectory of an air jet in a crossflow and to investigate the mechanisms involved in jet deflection. Experimental variables were the blowing rate, and the injection hole geometry cusp facing upstream (CUS), cusp facing downstream (CDS), round, swirl passage, and oblong. It is indicated that jet deflection is governed by both the pressure drag forces and the entrainment of free-stream fluid into the jet flow. For injection hole geometries with similar cross-sectional areas and similar mass flow rates, the jet configuration with the larger aspect ratio experienced a greater deflection. Entrainment arises from lateral shearing forces on the sides of the jet, which set up a dual vortex motion within the jet and thereby cause some of the main-stream fluid momentum to be swept into the jet flow. This additional momentum forces the jet nearer the surface. Of the jet configurations, the oblong, CDS, and CUS configutations exhibited the largest deflections. The results correlate well with film cooling effectiveness data, which suggests a need to determine the jet exit configuration of optimum aspect ratio to provide maximum film cooling effectiveness

The NASA Lewis integrated propulsion and flight control simulator

A new flight simulation facility was developed at NASA-Lewis. The purpose of this flight simulator is to allow integrated propulsion control and flight control algorithm development and evaluation in real time. As a preliminary check of the simulator facility capabilities and correct integration of its components, the control design and physics models for a short take-off and vertical landing fighter aircraft model were shown, with their associated system integration and architecture, pilot vehicle interfaces, and display symbology. The initial testing and evaluation results show that this fixed based flight simulator can provide real time feedback and display of both airframe and propulsion variables for validation of integrated flight and propulsion control systems. Additionally, through the use of this flight simulator, various control design methodologies and cockpit mechanizations can be tested and evaluated in a real time environment