Catalytic surface effects on contaminated space shuttle tile in a dissociated nitrogen stream

Visual inspection revealed contamination on the surface of tiles removed from the lower section of the space shuttle orbiter after the second flight of Columbia (STS-2). Possible sources of this contamination and the effect on surface catalycity are presented

Performance of an ablator for Space Shuttle inorbit repair in an arc-plasma airstream

An ablator patch material performed well in an arc plasma environment simulating nominal Earth entry conditions for the Space Shuttle. Ablation tests using vacuum molded cones provided data to optimize the formulation of a two part polymer system for application under space conditions. The blunt cones were made using a Teflon mold and a state of the art caulking gun. Char stability of formulations with various amounts of catalyst and diluent were investigated. The char was found to be unstable in formulations with low amounts of catalyst and high amounts of diluent. The best polymer system determined by these tests was evaluated using a half tile patch in a multiple High Temperature Reusable surface Insulation tile model. It was demonstrated that this ablator could be applied in a space environment using a state of the art caulking gun, would maintain the outer mold line of the thermal protection system during entry, and would keep the bond line temperature at the aluminum tile interface below the design limit

Observer and Particle Transformations and Newton's Laws

A frequently confused point in studies of symmetry violation is the distinction between observer and particle transformations. In this work, we consider a model in which a coefficient in the Standard-Model Extension leads to violations of rotation invariance in Newton's second law. The model highlights the distinction between observer and particle transformations.Comment: Presented at the Sixth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 17-21, 201

Population Genetics Analysis of the Grass Shrimp Palaemonetes Pugio Using Single Strand Conformation Polymorphism

Little is known about the genetic structure of grass shrimp, Palaemonetes pugio, populations or the effects the parasite Microphallus turgidus has on it. The objective of this study was to determine the amount of genetic diversity of the shrimp populations based on locality and parasite load. In order to examine the genetics of P. pugio, shrimp DNA was extracted and scanned using single stand conformation polymorphism. Results revealed P. pugio populations are highly conserved among localities. This suggests a significant amount of gene flow is taking place. Results also indicate there is no correlation between the most common host haplotype and parasite density, as shown in previous studies on host-parasite interactions. Further studies in this field will provide clearer answers in understanding the genetics of P. pugio

African American Early Literacy Development: An Integrative Review of the Research

An integrative review of the research literature was conducted in order to explore plausible explanations of the achievement gap. Research articles were analyzed for this review of the research literature. The findings of this integrative review were included and the educational implications for practice are delineated

Reading Researchers in Search of Common Ground: The Expert Study Revisited

The purpose of this book review was to analyze the main arguments regarding literacy instruction from various paradigms of research. The Foreword of this text was written by Dr. Patricia Edwards the Past President of the Literacy Research Association. As Dr. Edwards pointedly reveals in her endorsement of this text, “Reading researchers must find some common ground in order to provide teachers with the necessary strategies to teach children reading. Dr. Edwards takes a strong stance on the reading wars debate. This foreword leaves readers with key questions that are answered throughout the reading of this text such as, what is whole language? Is it a teaching method? Philosophy? Or is it both? Are proponents of phonics really only teaching letters and sounds? What about comprehension? Language development? During the reading and review of this work, it was clear that the search for common answers to many of the aforementioned questions were answered

Eliminating Book Deserts through Community Engagement

The purpose of this commentary is to discuss equity and advocacy regarding book deserts for children in urban schools. This commentary includes a critical review of the research literature, practical considerations for eliminating book deserts in schools, and developing a long-term community engagement program to resolve book deserts

Book Review - Rethinking the Role of Gender in Schools

The purpose of this book review is to critically analyze the text, Rethinking the Role of Gender in Schools. This review provides the strengths and weaknesses of the text as well as implications for youth and education professionals

Oscillatory subglacial drainage in the absence of surface melt

The presence of strong diurnal cycling in basal water pressure records obtained during the melt season is well established for many glaciers. The behaviour of the drainage system outside the melt season is less well understood. Here we present borehole observations from a surge-type valley glacier in the St Elias Mountains, Yukon Territory, Canada. Our data indicate the onset of strongly correlated multi-day oscillations in water pressure in multiple boreholes straddling a main drainage axis, starting several weeks after the disappearance of a dominant diurnal mode in August 2011 and persisting until at least January 2012, when multiple data loggers suffered power failure. Jökulhlaups provide a template for understanding spontaneous water pressure oscillations not driven by external supply variability. Using a subglacial drainage model, we show that water pressure oscillations can also be driven on a much smaller scale by the interaction between conduit growth and distributed water storage in smaller water pockets, basal crevasses and moulins, and that oscillations can be triggered when water supply drops below a critical value. We suggest this in combination with a steady background supply of water from ground water or englacial drainage as a possible explanation for the observed wintertime pressure oscillations