Space shuttle: Heat transfer investigation of the McDonnell-Douglas delta wing orbiter at a nominal Mach number of 10.5

Heat transfer tests for the delta wing orbiter were conducted in a hypervelocity wind tunnel. A 1.1 percent scale model was tested at a Mach number of approximately 10.5 over an angle of attack range from 10 to 60 degrees over a length Reynolds number range from 5 times 10 to the 6th power to 24 times 10 to the 6th power. Heat transfer results were obtained from model surface heat gage measurements and thermographic phosphor paint. Limited pressure measurements were obtained

The Effectiveness of the Inquiry Based Learning Method in a Private Independent School Environment

The purpose of this study was to examine the effectiveness of an inquiry-based learning model (IBLM) in a small, independent school educational environment. Seisan Academy (SA) implemented a new teaching philosophy that centered around an inquiry-based learning approach with a focus on developing a more student-centered culture at the school. This new program was implemented with little feedback or measurement regarding the effectiveness of the approach. This study also looked to address the lack of formal evaluation regarding the implementation of the IBLM. Multiple sampling strategies were implemented due to the mixed-methods nature of this study. Quantitative data collection included four years of American College Testing (ACT) scores and four years of school enrollment data from the years 2014 to 2017. This data was collected from four years of senior classes. The total number of ACT scores collected was for 309 students. SA’s enrollment and attrition rates from 2014 to 2017 were obtained from SA’s Blackbaud database. The quantitative data was used to identify trends or themes in ACT scores, enrollment figures, and attrition percentages and to measure the IBLM’s impact on these particular measures. The results of the research indicated an increase in student achievement scores during the school’s shift to an IBLM. The results of the study also established an increase in student enrollment and a decrease in student attrition that could be attributed to multiple factors related to increased constituent satisfaction. The study also indicated constituents of the school generally hold positive perceptions of the IBLM at SA. Finally, the study indicated the positive perceptions by constituents of the school in regard to a more student-centered culture

Managing Economic Risk from Invasive Species: Bug Options

Invasive insect species cause billions of dollars of direct and indirect damage to U.S. crops each year. The market for insuring insect damage is, however, far from complete. The objective of this study is to design and value insect derivatives, or "bug options," which would offer growers a market-based means for transferring risk of pest damage to speculators or others who may profit from higher insect populations. A bug option valuation model is developed and applied to Bemesia tabaci infestation in cotton. The results show that insect derivatives may become important risk management tools for a wide range of growers.Risk and Uncertainty,

Polygonal excitations of spinning and levitating droplets

The shape of a weightless spinning liquid droplet is governed by the balance between the surface tension and centrifugal forces. The axisymmetric shape for slow rotation becomes unstable to a non-axisymmetric distortion above a critical angular velocity, beyond which the droplet progresses through a series of 2-lobed shapes. Theory predicts the existence of a family of 3- and 4-lobed equilibrium shapes at higher angular velocity. We investigate the formation of a triangular-shaped magnetically levitated water droplet, driven to rotate by the Lorentz force on an ionic current within the droplet. We also study equatorial traveling waves which give the droplet 3, 4 and 5-fold symmetry.Comment: Supplementary information at http://www.nottingham.ac.uk/~ppzlev/Drople

On the Nature of Trapped-Hole States in CdS Nanocrystals and the Mechanism of their Diffusion

Recent transient absorption experiments on CdS nanorods suggest that photoexcited holes rapidly trap to the surface of these particles and then undergo diffusion along the rod surface. In this paper, we present a semiperiodic DFT model for the CdS nanocrystal surface, analyze it, and comment on the nature of both the hole-trap states and the mechanism by which the holes diffuse. Hole states near the top of the valence band form an energetic near continuum with the bulk, and localize to the non-bonding sp$^3$ orbitals on surface sulfur atoms. After localization, the holes form nonadiabatic small polarons that move between the sulfur orbitals on the surface of the particle in a series of uncorrelated, incoherent, thermally-activated hops at room temperature. The surface-trapped holes are deeply in the weak-electronic coupling limit and, as a result, undergo slow diffusion.Comment: 4 figure

Validation of magnetophonon spectroscopy as a tool for analyzing hot-electron effects in devices

It is shown that very high precision hot-electron magnetophonon experiments made on n+n−n+-GaAs sandwich device structures which are customized for magnetoresistance measurements can be very accurately modeled by a new Monte Carlo technique. The latter takes account of the Landau quantization and device architecture as well as material parameters. It is proposed that this combination of experiment and modeling yields a quantitative tool for the direct analysis of spatially localized very nonequilibrium electron distributions in small devices and low dimensional structures