Long Duration Exposure Facility M0003-5 recent results on polymeric films

The M0003-5 polymeric film specimens orbited on the LDEF M0003 Space Environment Effects on Spacecraft Materials were a part of a Wright Laboratories Materials Directorate larger thermal control materials experiment. They were selected from new materials which emerged from development programs during the 1978-1982 time frame. Included were materials described in the technical literature which were being considered or had been applied to satellites. Materials that had been exposed on previous satellite materials experiments were also included to provide data correlation with earlier space flight experiments. The objective was to determine the effects of the LDEF environment on the physical and optical properties of polymeric thin film thermal control materials, the interaction of the LDEF environment with silvered spacecraft surfaces, and the performance of low outgassing adhesives. Sixteen combinations of various polymeric films, metallized and unmetallized, adhesively bonded and unbonded films were orbited on LDEF in the M0003-5 experiment. The films were exposed in two separate locations on the vehicle. One set was exposed on the direct leading edge of the satellite. The other set was exposed on the direct trailing edge of the vehicle. The purpose of the experiment was to understand the changes in the properties of materials before and after exposure to the space environment and to compare the changes with predictions based on laboratory experiments. The basic approach was to measure the optical and physical properties of materials before and after long-term exposure to a low earth orbital environment comprised of UV, VUV, electrons, protons, atomic oxygen, thermal cycling, vacuum, debris and micrometeoroids. Due to the unanticipated extended orbital flight of LDEF, the polymeric film materials were exposed for a full five years and ten months to the space environment

Homogeneous and inhomogeneous contributions to the luminescence linewidth of point defects in amorphous solids: Quantitative assessment based on time-resolved emission spectroscopy

The article describes an experimental method that allows to estimate the inhomogeneous and homogeneous linewidths of the photoluminescence band of a point defect in an amorphous solid. We performed low temperature time-resolved luminescence measurements on two defects chosen as model systems for our analysis: extrinsic Oxygen Deficient Centers (ODC(II)) in amorphous silica and F+ 3 centers in crystalline Lithium Fluoride. Measurements evidence that only defects embedded in the amorphous matrix feature a dependence of the radiative decay lifetime on the emission energy and a time dependence of the first moment of the emission band. A theoretical model is developed to link these properties to the structural disorder typical of amorphous solids. Specifically, the observations on ODC(II) are interpreted by introducing a gaussian statistical distribution of the zero phonon line energy position. Comparison with the results obtained on F+ 3 crystalline defects strongly confirms the validity of the model. By analyzing experimental data within this frame, we obtain separate estimations of the homogenous and inhomogeneous contributions to the measured total linewidth of ODC(II), which results to be mostly inhomogeneous.Comment: 8 pages, 4 figure

Molecular Gas in Spiral Galaxies

In this review, I highlight a number of recent surveys of molecular gas in nearby spiral galaxies. Through such surveys, more complete observations of the distribution and kinematics of molecular gas have become available for galaxies with a wider range of properties (e.g., brightness, Hubble type, strength of spiral or bar structure). These studies show the promise of both interferometers and single-dish telescopes in advancing our general understanding of molecular gas in spiral galaxies. In particular, I highlight the contributions of the recent BIMA Survey of Nearby Galaxies (SONG).Comment: 8 pages, 1 figure. To appear in the proceedings of the 4th Cologne-Bonn-Zermatt-Symposium, "The Dense Interstellar Medium in Galaxies", which was held in Zermatt, Switzerland in September 200

Responsiveness of bovine cumulus-oocyte-complexes (COC) to porcine and recombinant human FSH, and the effect of COC quality on gonadotropin receptor and Cx43 marker gene mRNAs during maturation in vitro

Substantially less development to the blastocyst stage occurs in vitro than in vivo and this may be due to deficiencies in oocyte competence. Although a large proportion of bovine oocytes undergo spontaneous nuclear maturation, less is known about requirements for proper cytoplasmic maturation. Commonly, supraphysiological concentrations of FSH and LH are added to maturation media to improve cumulus expansion, fertilization and embryonic development. Therefore, various concentrations of porcine FSH (pFSH) and recombinant human FSH (rhFSH) were investigated for their effect on bovine cumulus expansion in vitro. Expression of FSHr, LHr and Cx43 mRNAs was determined in cumulus-oocyte complexes to determine whether they would be useful markers of oocyte competence. In serum-free media, only 1000 ng/ml pFSH induced marked cumulus expansion, but the effect of 100 ng/ml pFSH was amplified in the presence of 10% serum. In contrast, cumulus expansion occurred with 1 ng/ml rhFSH in the absence of serum. FSHr mRNA was highest at 0–6 h of maturation, then abundance decreased. Similarly, Cx43 mRNA expression was highest from 0–6 h but decreased by 24 h of maturation. However, the relative abundance of LHr mRNA did not change from 6–24 h of maturation. Decreased levels of FSHr, LHr and Cx43 mRNAs were detected in COCs of poorer quality. In conclusion, expansion of bovine cumulus occurred at low doses of rhFSH in serum-free media. In summary, FSHr, LHr and Cx43 mRNA abundance reflects COC quality and FSHr and Cx43 mRNA expression changes during in vitro maturation; these genes may be useful markers of oocyte developmental competence

The Color Line and Georgia History Textbooks: A Content Analysis

The purpose of this research is to define racialized textbook bias, conduct a content analysis of Georgia history textbooks, and answer the following question: how is race framed in contemporary Georgia history textbooks? A content analysis of nine Georgia history textbooks was completed for grades two and eight. A Du Boisian theoretical framing of race prejudice as the macro-social condition of the micro-social process of race was an integral component of the content analysis. The findings revealed the existence of racialized textbook bias in the form of marginalization, compartmentalization, and omission suggesting the continuation of White supremacy and Black oppression in the process of education in Georgia public schools

Going Beyong the Third Grade Science Kit: An Integrated Thematic Approach

A project has been developed to aid in the design of a third grade science program and/or to be used as a supplement to any existing third grade science curriculum. The project has been organized into fourteen lesson plans. Each lesson plan includes an overview of the lesson, student learning objectives matched to the Washington State Essential Academic Learning Requirements, activities, a list of required materials, an outline of instruction, and the name of a trade book to compliment the lesson. Current literature and research regarding the topic of integrated curriculum were explored

Ultimate Strength Prediction in Fiberglass/Epoxy Beams Subjected to Three-Point Bending Using Acoustic Emission and Neural Networks

The research presented herein demonstrates the feasibility of predicting ultimate strengths in composite beams subjected to 3-point bending using a neural network analysis of acoustic emission (AE) amplitude distribution data. Fifteen unidirectional fiberglass/epoxy beams were loaded to failure in a 3-point bend test fixture in an MTS load frame. Acoustic emission data were recorded from the onset of loading until failure. After acquisition, the acoustic emission data were filtered to include only data acquired up to 80 percent of the average ultimate load. A backpropagation neural network was constructed to predict the ultimate failure load using these AE amplitude distribution data. Architecturally, the network consisted of a 61 processing element input layer for each of the event frequencies, a 13 processing element hidden layer for mapping, and a single processing element output layer for predicting the ultimate load. The network, trained on seven beams, was able to predict ultimate loads in the remaining eight beams with a worst case error of +4.34 percent, which was within the desired goal of ± 5 percent. A second analysis was performed using a Kohonen self organizing map and multivariate statistical analysis. A Kohonen self organizing map was utilized to classify the AE data into 4 failure mechanisms. Then multivariate statistical analysis was performed using the number of hits associated with each failure mechanism to develop a prediction equation. The prediction equation was able to predict the ultimate failure load with a worst case error of-11.34 percent, which was well outside the desired goal of ± 5 percent. This was thought to be the result of noisy or sparse data, since statistical predictions are inherently sensitive to both, whereas backpropagation neural networks are not

Movement Research: Exploring Liminality of Dance

In the sphere of fine arts, dance is often measured against canonized European agents, but this project endeavors to gain greater awareness for this field beyond traditional valuation. Moreover, this project aims to crack the portrayal of the “dance world” to show dance as permeating our everyday space, and not something we can quantify as different or separate. In a capitalist society where bodies are constantly bombarded with aesthetic, political, and cultural values, dance can reflect or subvert those projections. How can we value dance in new ways that resist corporal commodification? Moreover, can the promotion of dance beyond an association with only spectacle and pleasure lead to more accessible ways to perform and enjoy dance? By including observers within the dance itself, how can we improve our working definitions of what it means to dance, to be a dancer, and to view dance? This project explores these questions through the practice of dance creation as research, and the approach to dance as inherently liminal- dance in the quotidian, dance as formation of identity through expression, and dance as accessible to all

The Nature of beads

The purpose of this thesis is to explore the various qualities of nature through the concept of the bead. A series of beads has been created whose aesthetic elements enhance the essence of nature and the spirit of the individual. With these pieces I wanted to express my sensitivity and feelings about nature relating to seasons of the year and personal memories. It is my hope that this body of work will heighten an awareness of nature and arouse thought and curiosity about beads