Measurement and correlation of aerodynamic heating to surface corrugation stiffened structures in thick turbulent boundary layers

The flow conditions for which heating distributions were measured on corrugated surfaces and wavy walls in turbulent boundary layers are shown, along with the ratio of the displacement thickness to the roughness height versus the local edge Mach number for an equivalent smooth surface. The present data are seen to greatly extend the range of data available on corrugated surfaces in turbulent boundary layers. These data were obtained by testing fullscale corrugation roughened panels in the wall boundary layer of a supersonic and hypersonic wind tunnel. The experimental program used to obtain the data is described. The data are analyzed and correlated in terms of the pertinent flow and geometric parameters. The developed correlations are compared with the available thin boundary layer data, as well as with previously published correlation techniques

Transverse emittance dilution due to coupler kicks in linear accelerators

One of the main concerns in the design of low emittance linear accelerators (linacs) is the preservation of beam emittance. Here we discuss one possible source of emittance dilution, the coupler kick, due to transverse electromagnetic fields in the accelerating cavities of the linac caused by the power coupler geometry. In addition to emittance growth, the coupler kick also produces orbit distortions. It is common wisdom that emittance growth from coupler kicks can be strongly reduced by using two couplers per cavity mounted opposite each other or by having the couplers of successive cavities alternation from above to below the beam pipe so as to cancel each individual kick. We therefore analyze consequences of alternate coupler placements. We show here that for sufficiently large Q values, alternating the coupler location from before to after the cavity leads to a cancellation of the orbit distortion but not of the emittance growth, whereas alternating the coupler location from before and above to behind and below the cavity cancels the emittance growth but not the orbit distortion. These compensations hold even when each cavity is individually detuned, e.g. by microphonics. Another effective method for reducing coupler kicks that is studied is the optimization of the phase of the coupler kick. This technique is independent of the coupler geometry but relies on operating on crest. A final technique studied is symmetrization of the cavity geometry in the coupler region with the addition of a stub opposite the coupler, which reduces the amplitude of the off axis fields and is thus effective for off crest acceleration as well. We show applications of these techniques to the energy recovery linac (ERL) planned at Cornell University

Aerothermodynamic Assessment of Corrugated Panel Thermal Protection Systems

The feasibility of using corrugated panels as a thermal protection system for an advanced space transportation vehicle was investigated. The study consisted of two major tasks: development of improved correlations for wind tunnel heat transfer and pressure data to yield design techniques, and application of the design techniques to determine if corrugated panels have application future aerospace vehicles. A single-stage-to-orbit vehicle was used to assess advantages and aerothermodynamic penalties associated with use of such panels. In the correlation task, experimental turbulent heat transfer and pressure data obtained on corrugation roughened surfaces during wind tunnel testing were analyzed and compared with flat plate data. The correlations and data comparisons included the effects of a large range of geometric, inviscid flow, internal boundary layer, and bulk boundary layer parameters in supersonic and hypersonic flow

Riemann zeros, prime numbers and fractal potentials

Using two distinct inversion techniques, the local one-dimensional potentials for the Riemann zeros and prime number sequence are reconstructed. We establish that both inversion techniques, when applied to the same set of levels, lead to the same fractal potential. This provides numerical evidence that the potential obtained by inversion of a set of energy levels is unique in one-dimension. We also investigate the fractal properties of the reconstructed potentials and estimate the fractal dimensions to be $D=1.5$ for the Riemann zeros and $D = 1.8$ for the prime numbers. This result is somewhat surprising since the nearest-neighbour spacings of the Riemann zeros are known to be chaotically distributed whereas the primes obey almost poisson-like statistics. Our findings show that the fractal dimension is dependent on both the level-statistics and spectral rigidity, $\Delta_3$, of the energy levels.Comment: Five postscript figures included in the text. To appear in Phys. Rev.

TECHNOLOGY IN A GIFTED AND TALENTED MATH CLASSROOM: HOW IT IMPACTS STUDENTS\u27 PROBLEM SOLVING AND MATHEMATICAL LEARNING

Technology has advanced greatly over the past few decades and the surge in the industry has impacted the workplace. As a result, K-12 education has worked to integrate 21st century skills into curriculum. Many times this is through STEM classes. This study examined the impact technology had on gifted and talented students’ achievement and creative construction. During a unit on Transformations, a control group received traditional instruction, while an experimental group received traditional instruction with an added technology component. A pre and posttest were given to both groups to measure student success with the geometry content. Results indicated that the technology component did not have a major impact on student achievement. Both the control and experimental group showed mastery of the standards and concepts. The technology component did increase students’ use of correct content vocabulary

Density and Mass Effect on the Development of Phormia regina

Forensic entomology is the application of the study of arthropods to the criminal justice system. This is primarily done through the development of a post mortem interval (PMI) based the insect evidence present. A practitioner must be able to determine the age of the insect through temperature data. One factor influencing the temperature dependent development is gregarious behavior. Current literature describes a faster development rate due to an increase in feeding efficiency and temperatures produced by this aggregate. However, there is very little literature defining a minimum number needed to induce this effect and little to none on it for Phormia regina. Two experiments were done to explore the effect of aggregation on P. regina juveniles. Both experiments used growth chambers set to 25°C and egg masses from lab reared colonies. The first experiment used two chambers with differing densities of larvae at 25, 50, 100, and 200 in 490ml plastic containers with 2cm of pine shavings. Larvae were reared on 2g of liver in 29.5ml plastic cups in the containers and liver was added as needed. Each container was subsampled with replacement every day to check the development of the larvae (10-25%) until adult eclosion. Aggregate temperatures were checked with a digital heat thermometer gun (TES) and probe throughout the duration of the experiment. No significant difference in development was observed. The mass temperatures in experiment one did not cause a decrease in development time as reported by the literature and the 100 counts had a higher average than the 200s. Experiment two was designed to explore this by increasing the space provided from a 490 ml container to a 1.42L one and to increase the feeding cup size from 29.5ml to 88.7ml. 25 and 200 larvae were provided 5g of liver to feed on initially.. Development times were significant longer for the 200 counts in the third instar and caused a downstream effect. Advisor: Leon G. Higle