Wind-tunnel Tests of the Fowler Variable-area Wing

The lift, drag, and center of pressure characteristics of a model of the Fowler variable-area wing were measured in the NACA 7 by 10 foot wind tunnel. The Fowler wing consists of a combination of a main wing and an extension surface, also of airfoil section. The extension surface can be entirely retracted within the lower rear portion of the main wing or it can be moved to the rear and downward. The tests were made with the nose of the extension airfoil in various positions near the trailing edge of the main wing and with the surface at various angular deflections. The highest lift coefficient obtained was C(sub L) = 3.17 as compared with 1.27 for the main wing alone

Search, Moral Hazard, and Price Dispersion

We study the effects of insurance coverage on consumer search behavior and the pricing of services covered by insurance, constructing a general equilibrium model of moral hazard in search with an endogenous price distribution. When an insured event occurs, households request quotes from firms, who offer a homogenous service at various prices. We show that lower coinsurance rates reduce the amount of search by households, allowing firms to increase their prices. Hence, moral hazard in search is far more costly than shown in previous models, which ignored equilibrium firm response to changes in consumer search behavior.

The Shields Family: A Dichotomy of Race in US Society through Two Family Lines

The history of the Shields families of North and South Carolina, beginning with William Bryant Shields Sr. and Moses Shields respectively, offer dichotomous responses to American racial hierarchies over the decades. Generations of race mixing within the Shields family has its roots in the sons of Irish immigrants pursuing relationships with enslaved women. The one-sided nature of the power dynamic in these relationships takes on different dimensions in the lives of the mixed-race children of William Bryant Shields Sr. and the lives of Moses’ son, Henry Wells Shields, Henry’s slave Melvinia Shields, and her children. Both family lines take efforts to repress their black ancestry, one primarily through dilution through marriage and the other through a refusal of formal acknowledgement, which ironically enabled some of their children to flourish in African American society. The permeability of race can be gleaned through these two Shields family lines both in how they went about repressing their ties to enslaved black women and how these culminated in the present-day Shields descendants, Roseanne Cash and Michelle Obama

Parachute Extraction of a Generic Store from a C-130; a CFD Proof of Concept

This thesis encompasses a feasibility analysis of a parachute extracted generic precision guided munition from the cargo bay of a C-130 aircraft in flight. This analysis utilizes the USAF Beggar code and incorporates full physics effects as well as aerodynamic loading assuming an inviscid aircraft and viscous store for a time-accurate solution. Both an immediate and time varying application of the parachute force are utilized as well as two different ordnance body styles at zero and 5 degrees AOA with the store placed on centerline and offset in the cargo bay. The time accurate parachute model is based on empirical data and more closely follows the force fall off as the parachute slows down during the extraction process. Both store body styles were successfully extracted from the cargo bay without contacting any portion of the delivery aircraft, following a safe trajectory down and away from all of the release conditions. The extraction took 1.7 seconds with the immediate application of the parachute force and 2.1 seconds when the time varying model was applied. The maximum roll seen during an extraction was 13 degrees, which was the largest movement on any axis

Time dependence in perpendicular media with a soft underlayer

In this paper we describe measurements of magnetic viscosity or time dependence in magnetic thin films suitable for use as perpendicular recording media. Generally, such effects cannot be measured using conventional magnetometry techniques due to the presence of a thin (0.1 mum) soft underlayer (SUL) in the media necessary to focus the head field. To achieve our results we have developed an ultrastable MOKE magnetometer, the construction of which is described. This has enabled us to measure nominally identical films with and without the presence of the SUL. We find that the presence of the SUL narrows the energy barrier distribution in the perpendicular film increasing the nucleation field (H-n), reducing the coercivity (H-c) and results in an increase in the squareness of the loop. This in turn results in an increase in the magnitude of the viscosity in the region of the H-c but that the range of fields over which the viscosity occurs is reduced