Microscopic and Metallurgical Aspects of the Space Shuttle Columbia Accident Investigation and Reconstruction

The Space Shuttle Columbia was descending for a landing at the Kennedy Space Center (KSC) on February 1, 2003. Approximately 20 minutes prior to touchdown, the Columbia began disintegrating over the western United States; the majority of debris eventually impacted in eastern Texas and western Louisiana. A monumental effort eventually recovered approximately 84,000 pieces of debris, approximately 38% of the Orbiter's original dry weight. The debris was transported to KSC, where the items were catalogued and evaluated. Critical areas of interest, such as the left and right leading edge surfaces and the underside of the ship, were placed upon a grid to aid in the reconstruction. Items of interest included metallic structures, reinforced carbon-carbon composites, and ceramic heat insulation tiles. Many of the leading edge elements had re-solidified metallic deposits spattered on them. These deposits became known as slag and were one of the main focuses of the investigation. In order to help determine the sequence of events inside the left wing during the accident, the slag's composition, layering order, and directionality of deposition were studied. A myriad of analytical tests were performed in an attempt to ascertain the compositional and depositional characteristics of selected slag deposits, including the ordering of deposited layers within each individual slag deposit harvested. Initially, Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy (SEM/EDX) were performed to quickly characterize the overall composition of individual slag deposits: SEM utilizes a narrowlyfocused high-energy electron beam impinging upon a specimen. The incident beam excites and liberates lower energy secondary electrons, which are detected and analyzed, providing a visual representation of the sample's surface topography. EDX also relies on an incident electron beam, except an EDX unit measures X-ray energies generated by the impinging beam. Each element generates a unique X-ray signature; the EDX detector measures these discreet energies. EDX actually penetrates approximately 2 microns into the bulk of the sample. However, random examination of various portions of slag, coupled with the semiquantitative nature of the SEM/EDX analysis, did not yield convincingly pertinent data. Therefore, X-ray dot mapping was conducted, which provided more understandable data, both in terms of slag layering and composition. An X-ray dot map is generated by performing numerous EDX scans for individual elements, then compiling the scans in a visual representation. Eventually, specimens consisting of not only the slag, but of the adjacent RCC substrate as well were cross-sectioned. X-Ray dot mapping of the materialographicallymounted and -polished cross- sections provided a visual representation of both the layering sequence and compositional characteristics of the slag. Contemporaneously, Electron Spectroscopy for Chemical Analysis/X-Ray Photoelectron Spectroscopy (ESCA/XPS) and powdered X-Ray Diffraction (XRD) were performed to further characterize the deposits and to attempt to identify what, if any, compounds were present. The ESCA/XPS analysis allowed the analyst to "sputter" into the sample with an electron gun, aiding in the identification of the layering sequence. XPS uses photons, rather than electrons, which impinge upon the surface of the sample. XPS measures the electrons emitted from within the first 5 nm of the sample's surface. The XRD measures the scatter angles of incident X-rays; the angle and intensity of scatter depend upon the crystalline structure of the pulverized sample. XRD is considered a qualitative rather than quantitative technique. ESCA/XPS revealed that the final layer to deposit was predominantly carbonaceous. XRD was successful in identifying specific compounds, such as Al 2O3, Al and/or Al3 21SiO47, mullite (3(Al2)O3 -SiO2), and nickel-aluminides. Eventually, Electron MicroProbe Analysis (EMPA) was conducted on the marialographically-prepared cross- sections of selected slag deposits. Microprobe combines SEM and Wavelength Dispersive X-Ray Spectroscopy (WDS), and, like EDX, uses a narrowly-focused high-energy electron beam impinging upon a specimen to elicit, in the case of EPMA, characteristic X-rays with specific wavelengths. This quantitative, analytical tool proved the most useful in determining depositional layering and composition of the slag deposits. This information was utilized in verifying the location of the breach in the left leading edge of the wing of the Columbia

Airflow Model Testing to Determine the Distribution of Hot Gas Flow and O/F Ratio Across the Space Shuttle Main Engine Main Injector Assembly

Engine 0209, the certification engine for the new Phase 2+ Hot Gas Manifold (HGM), showed severe deterioration of the Main Combustion Chamber (MCC) liner during hot fire tests. One theory on the cause of the damage held that uneven local distribution of the fuel rich hot gas flow through the main injector assembly was producing regions of high oxidizer/fuel (O/F) ratio near the wall of the MCC liner. Airflow testing was proposed to measure the local hot gas flow rates through individual injector elements. The airflow tests were conducted using full scale, geometrically correct models of both the current Phase 2 and the new Phase 2+ HGMs. Different main injector flow shield configurations were tested for each HGM to ascertain their effect on the pressure levels and distribution of hot gas flow. Instrumentation located on the primary faceplate of the main injector measured hot gas flow through selected injector elements. These data were combined with information from the current space shuttle main engine (SSME) power balances to produce maps of pressure, hot gas flow rate, and O/F ratio near the main injector primary plate. The O/F distributions were compared for the different injector and HGM configurations

Mothering modes: analyzing mother roles in novels by twentieth-century United States women writers

For this dissertation, the following novels have been chosen as examples of the many issues that are involved in mothering in United States society: Chapter 1: Dorothy Allison’s Bastard Out of Carolina and Toni Morrison’s Beloved, Chapter 2: Toni Morrison’s Song of Solomon and Dorothy West’s The Wedding, Chapter 3: Amy Tan’s The Kitchen God’s Wife and Christina García’s Dreaming in Cuban, and Chapter 4: Betty Smith’s A Tree Grows in Brooklyn and Paule Marshall’s Brown Girl, Brownstones. For this study, the term “mothering” is specifically related to the rearing of children by the female parent. Rearing is defined as the bringing up of a child to maturity and at least to the legal age of eighteen. In “Mothers at Work: Representations of Maternal Practice in Literature,” Elizabeth Bourque Johnson examines the following definition of mothering: “Mothering is a job, a kind of work. The word mother may also indicate a relationship or a title or a way of caring, but primarily a mother is a worker, a person who takes responsibility for the care and development of a child” (22). In this dissertation, I argue that oppressive circumstances in the examples in these novels create similar coping strategies for the mother characters, especially when mothering daughters. In addition and contrary to what some might believe, those coping strategies are not confined exclusively to particular cultural groups. The chapters of this study show how different mothers who rear children under different negative circumstances may benefit from similar coping strategies, and they examine these coping strategies from the least to the greatest examples of their success

IEC Fusor Mobile Shielding Unit

The VCU Inertial Electrostatic Confinement (IEC) Fusor Senior Design Project provides Virginia Commonwealth University (VCU) with a mobile fusor complete with the necessary shielding to protect operators as well as the general public from potentially hazardous radiation. The VCU IEC fusor is a Farnsworth-Hirsch type reactor, and consists of five basic components; a high voltage power supply, vacuum system, gas regulation system, primary reactor vessel assembly, and radiation shielding. These components were serviced and reassembled on a customized mobile cart. In addition to these components, a specimen holder and viewing monitor were added to the design. The specimen holder provides a practical method for neutron activation experiments, while the viewing monitor allows for safer visualization and operation of the fusor. An engineered cart provides the operator easy transportation of the shielding, fusor, and necessary components. The shielding consists of layers of High Density Polyethylene (HDPE), Borated Polyethylene (BPE), and lead to minimize radiation dose exposure to limits acceptable by the Nuclear Regulatory Commission (NRC). A camera inside the shielding is connected to a display monitor in order to provide a visual depiction of the deuterium ionization and fusion process. This allows operators and audiences to view the internal workings of the fusor from a safe distance. Lastly, an operator’s manual has been drafted to assist future operators with running the fusor. With these additions to the existing design, the fusor assembly serves as a vital asset for researchers, as well as an educational tool for students and teachers.https://scholarscompass.vcu.edu/capstone/1199/thumbnail.jp

USING THE INTERNATIONAL CLASSIFICATION OF FUNCTIONING, DISABILITY, AND HEALTH TO PREDICT PARTICIPATION IN ADULTS WITH PARKINSON’S DISEASE: THE ROLE OF POSITIVE PSYCHOLOGICAL CAPITAL

Participation is generally considered the ultimate rehabilitation outcome and, for individuals with progressive illnesses, elucidating the factors that impact participation is critical. Parkinson’s disease (PD) is a chronic degenerative, neurological condition affecting nearly 1 million people in the United States, making PD the second most prevalent neurodegenerative disorder. PD has a profound negative effect on functioning and activity, but limited literature exists assessing the relationship between PD and community participation. The purpose of this study was to use the World Health Organization (WHO) International Classification of Functioning, Disability, and Health (ICF) as a framework for explaining how PD affects participation. Additionally, because the ICF explains the impact of chronic illness and disability as consisting of interactions between different contextual and disease-related factors, this investigation also addressed whether the personal factors, Positive Psychological Capital (PsyCap), mediated the relationship between functioning with PD and community participation. A total of 114 individuals were surveyed from peer-led PD support groups in a Midwestern state. The study examined the individual and collective contributions of demographic characteristics, activities/functioning, environmental factors, and personal factors on community participation. Results from the hierarchical regression analysis suggest that demographic characteristics account for only 15% of the variance in participation, but when functioning was added to the model, 65% of the variance was accounted for. The addition of environmental and personal covariates did not result in any significant change in overall variance in participation. These results, along with the strong, positive linear correlations between functioning and participation (r = .78), indicate that functioning largely predicts an individual’s participation. The study also sought to identify any mediating effect of personal factors (PsyCap) on the relationship between functioning and participation. The results indicated that the completely standardized indirect coefficient was not significant, b = .065, SE = .0617, 95% CI = -.213, .029, with 0 falling within the CI, which confirms no significant effect of the mediator PsyCap. The study contributes new knowledge to the association between the symptoms associated with PD and one’s community participation. Clearly, functioning is the primary predictor of participation. The lack of mediation of PsyCap, again, supports the strength of the relationship between functioning and participation. Although PsyCap did not mediate the relationship, implications for future research are discussed

Roles for Chd7 in Zebrafish Development with Implications for Human Disease

The Chromodomain Helicase DNA Binding Protein (CHD) family consists of a group of nine known proteins that function in controlling DNA dynamics and transcription. The CHD family member of interest in this work, Chromodomain helicase DNA-binding protein 7 (chd7), has been implicated in human CHARGE (coloboma of the eye, heart defects, atresia of the choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness) Syndrome and Idiopathic Scoliosis, however little is known about the roles this gene plays during development. Using zebrafish as a model system, morpholino antisense technology, whole mount in situ hybridization (WISH), and a relatively new protocol, RNA-Seq, we provide evidence of several developmental defects resulting from Chd7 knockdown as well as describe several genes that exhibit significant differential expression upon Chd7 knockdown. We provide evidence that zebrafish embryos highly express chd7 in the retina, brain and somite boundaries. We demonstrate that a reduction in Chd7 synthesis results in laterality defects in the expression of somitogenesis genes, consistent with the hypothesis that this chromatin remodeler is necessary for the proper development of the long axis of the body and may be involved in the onset of human scoliosis. We show that the presence of Chd7 is crucial for proper neural, retinal and vertebral development in zebrafish and that loss of function of Chd7 resulted in several morphological defects similar to those observed in human patients with CHARGE syndrome. Finally, this work is the first transcriptome-wide study analyzing genetic changes in response to knockdown of a member of the Chromodomain Helicase DNA Binding Protein family. Using RNA-Seq we were able to identify and quantify differentially expressed genes in chd7 morphant zebrafish embryos compared to control morphant zebrafish embryos. These data were consistent with our knockdown experiments as well as with putative roles for Chd7 in human diseases. In an effort to make a broader impact, we extended the use of zebrafish beyond scientific research and described several different methods of using zebrafish in the undergraduate laboratory classroom. First, we described the use of WISH in the classroom to help students form connections between molecular and organismal biology and then described the use of two model organisms, zebrafish and C. elegans, in the classroom to help students understand how genes and the environment interact to affect organismal development. Cumulatively, this work is an example of interdisciplinary study both in the research laboratory as well as in the classroom. It involves the intensive study of a chromatin remodeler, Chd7, and makes important connections between Chd7 knockdown in zebrafish and human diseases. It also describes the pedagogical advantages of model organisms with respect to providing a rich and integrative experience for undergraduate biology majors

Competition Policy, Capacity Building, and Selective Adaptation: Lessons from Japan\u27s Experience

One potential tool to assist in this regard is Potter’s selective adaptation model. The model identifies the role of local conditions in the adaptation of foreign rules. It has been successfully applied to China’s adaptation of property law, administrative law, and corporate governance rules. The question we address is whether and how the model can be applied to the adaptation of competition policy. This Article reflects our first steps towards an answer

Political Participation of Registered Nurses: A Correlational Study

This study analyzes and provides a base line description of the political participation of nurses practicing in hospitals. The study explores the relationships between political participation and the variables: self-esteem, personal control, political efficacy and critical thinking. The theoretical framework for designing the questionnaire was based on the Political Participation Model (Verba and Nie, 1972) and the Political Process Participation Questionnaire (Archer, 1983). Design of the Political Efficacy Scale was based on the Subjective Political Competence Scale (Almond and Verba, 1963) and the Political Efficacy Scale (Campbell, Gurin and Miller, 1954). Self-esteem was measured by the Self-Esteem Inventory (Coopersmith, 1967). Personal Control was Measured by the Internal, Powerful Others, and Chance Locus of Control Scale, (Levenson and Miller, 1976). Critical thinking ability was measured by the Critical Thinking Appraisal (Watson and Glaser, 1980). The research study group consisted of 56 registered nurses who were practicing for five or more years in hospitals in San Diego County, California. Correlation procedures and analysis of variance were employed to test for significance and to determine whether relationships exist between political participation and the variables. A significant relationship exists between political participation and critical thinking, self-esteem and political efficacy. Nurses agreed to some extent with participation in politics, but reported a low level of participation in the political process within the last year

Drawing the Primetime Color Line: A Critical Discourse Analysis of Interracial Marriages in Television Sitcoms

Changes throughout history, particularly those surrounding race relations in the U.S., frequently have a direct effect on personal social experience and the current structure of society. Although public discourse often emphasizes the rhetoric of racial progression, subtle racism abounds – both in society and in media – masked under the façade of equality. This is especially true when examining race relations between Blacks and Whites, particularly those involved in intimate heterosexual interracial relationships, as they have traditionally been viewed as negative, dangerous, and threatening to the status quo. Television representations are often socially and culturally rooted with real issues, hence their mass appeal. Critical television studies involving race (and gender, class, and power) situate questions about these representations and struggles within the context of American entertainment media. By engaging the text together with context, in line with cultural studies, meanings can be deduced from media discourse. As such, this study explores and traces Black/White interracial intimate relationship portrayals on exemplary American network television sitcoms representing the 1970 and 2010 decades. Building on the intersection of existing mass communication and cultural studies research about both intimate interracial pairings in American society and in mainstream television, this dissertation focuses exclusively on the first season of two situational comedies featuring a heterosexual Black/White interracial couple that were broadcast during primetime hours on major commercial networks – The Jeffersons (CBS/1975) and Happy Endings (ABC/2011). Using critical race theory, this critical discourse analysis systematically examines the U.S. television industry-created sitcoms’ depictions of interracial marriages between Black and White individuals. Although important social, legal, and political events pertaining to race relations took place during the study’s chosen time frame of 1975-2011, little variation existed in the thematic representations of Black/White interracial couples. Furthermore, consistencies in themes between each sitcom existed