Radiation of plasma waves by a conducting body moving through a magnetized plasma

A theory is presented describing energy loss due to radiation of plasma waves by a conducting body moving through a magnetized plasma, which makes it possible to estimate the total power radiated at all frequencies. Using energy conservation and a source current deduced by physical reasoning, numerical predictions were made for the power radiated. It was found that radiation is produced at all frequencies for which one of the plasma modes has zero phase velocity in some direction

Chemical analysis of polymer blends via synchrotron X-ray tomography

Material properties of industrial polymer blends are of great importance. X-ray tomography has been used to obtain spatial chemical information about various polymer blends. The spatial images are acquired with synchrotron X-ray tomography because of its rapidity, good spatial resolution, large field-of-view, and elemental sensitivity. The spatial absorption data acquired from X-ray tomography experiments is converted to spatial chemical information via a linear least squares fit of multi-spectral X-ray absorption data. A fiberglass-reinforced polymer blend with a new-generation flame retardant is studied with multi-energy synchrotron X-ray tomography to assess the blend homogeneity. Relative to other composite materials, this sample is difficult to image due to low x-ray contrast between the fiberglass reinforcement and the polymer blend. To investigate chemical composition surrounding the glass fibers, new procedures were developed to find and mark the fiberglass, then assess the flame retardant distribution near the fiber. Another polymer blending experiment using three-dimensional chemical analysis techniques to look at a polymer additive problem called blooming was done. To investigate the chemical process of blooming, new procedures are developed to assess the flame retardant distribution as a function of annealing time in the sample. With the spatial chemical distribution we fit the concentrations to a diffusion equation to each time step in the annealing process. Finally the diffusion properties of a polymer blend composed of hexabromobenzene and o-terphenyl was studied. The diffusion properties were compared with computer simulations of the blend

Solving modal equations of motion with initial conditions using MSC/NASTRAN DMAP. Part 1: Implementing exact mode superposition

Within the MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) module TRD1, solving physical (coupled) or modal (uncoupled) transient equations of motion is performed using the Newmark-Beta or mode superposition algorithms, respectively. For equations of motion with initial conditions, only the Newmark-Beta integration routine has been available in MSC/NASTRAN solution sequences for solving physical systems and in custom DMAP sequences or alters for solving modal systems. In some cases, one difficulty with using the Newmark-Beta method is that the process of selecting suitable integration time steps for obtaining acceptable results is lengthy. In addition, when very small step sizes are required, a large amount of time can be spent integrating the equations of motion. For certain aerospace applications, a significant time savings can be realized when the equations of motion are solved using an exact integration routine instead of the Newmark-Beta numerical algorithm. In order to solve modal equations of motion with initial conditions and take advantage of efficiencies gained when using uncoupled solution algorithms (like that within TRD1), an exact mode superposition method using MSC/NASTRAN DMAP has been developed and successfully implemented as an enhancement to an existing coupled loads methodology at the NASA Lewis Research Center

Solving Modal Equations of Motion with Initial Conditions Using MSC/NASTRAN DMAP

By utilizing MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) in an existing NASA Lewis Research Center coupled loads methodology, solving modal equations of motion with initial conditions is possible using either coupled (Newmark-Beta) or uncoupled (exact mode superposition) integration available within module TRD1. Both the coupled and newly developed exact mode superposition methods have been used to perform transient analyses of various space systems. However, experience has shown that in most cases, significant time savings are realized when the equations of motion are integrated using the uncoupled solver instead of the coupled solver. Through the results of a real-world engineering analysis, advantages of using the exact mode superposition methodology are illustrated

Introduction to School and District Leadership in an Era of Accountability: Chapter 1

Our fourth book in the International Research on School Leadership series focuses on school leadership in an era of high-stakes accountability. Fueled by sweeping federal education accountability reforms, such as No Child Left Behind (NCLB) and Race to the Top (RttT) in the United States and Australia’s Performance Measurement and Reporting Task Force, school systems around the world are being forced to increase academic standards, participate in high-stakes testing, and raise evaluation standards for teachers and principals. These results-driven reforms are intended to hold educators “accountable for student learning and accountable to the public” (Anderson, 2005, p.2). While policymakers and the public debate the merits of student achievement accountability measures, P-12 educational leaders do not have the luxury to wait for clear guidance and resources to improve their schools and operating systems. Instead, successful leaders must balance the need to create learning communities, manage the organizational climate, and encourage community involvement with the consequences testing has on teacher morale and public scrutiny. The chapters in this volume clearly indicate that school leaders attending to these potentially competing forces affects their problem-solving strategies, their ability to facilitate change, and encourage community involvement. 123 In soliciting manuscripts for this volume, we encouraged authors to explore successful leadership being practiced by building and district level leaders as external pressures to improve student achievement have increased. Our goal was to create an edited book that examines successful school and district leadership during the accountability era from multiple perspectives. Our call for manuscripts asked potential authors to consider these important questions: - How do educational leaders successfully manage the politics of accountability? - To what degree are innovation and creativity affected as accountability increases? - What are effective ways of maintaining staff morale and community involvement as the pressure to raise student achievement rises?- Why do some schools thrive during times of increasing accountability? - How has accountability shaped what schools and districts do to build leadership capacity, professional learning communities, and continuous improvement? - During the accountability era, how have school leadership practices changed? Have these changes led to improved student achievement? - How have school leaders used elements of accountability (e.g., transparency, testing, data disaggregation) to inform their practice? This first chapter in the book volume provides a brief overview of the theme of the book and then an introduction for each of the eleven chapters, with links to the full book

The Multiple Futures of the Field of Educational Leadership Research and Practice – An Introduction

As the sixth volume in the International Research on School Leadership series, the contributing authors in this volume consider the history, challenges, and opportunities of the field of research and practice in educational leadership and administration in schools and districts. Ten years after the work of Firestone and Riehl (2005) and their contributing authors, our aim with the present volume was to summarize and update the work of the field, and provide a space to consider the multiple futures of educational leadership in schools and districts, as both challenges and opportunities. The first decade of the twenty-first century brought significant critiques, challenges, and competition to the research and practice of training leaders and administrators of schools and districts around the world. Congruently, the field experienced significant growth and change, as multiple new sub-domains flourished and were founded. Thus, in this volume we were delighted to included excellent chapters from multiple authors that considered the duality of the challenges and opportunities of: • The work of the field of educational leadership and administration research to date. • The opportunities and challenges of new visions of leadership in traditional and non-traditional schools. • The evolving state of research evidence in educational leadership and the increasing sophistication of multiple methodologies, including qualitative research, quantitative modeling, the ability to test theory, and the increasing opportunities brought on by the intersection of data, research, and practice. • The preparation of educational leaders. • And the emerging trends in the professional development of school leaders. The authors of the nine chapters in the present book volume took on this challenge of confronting the duality of not only including the past as we look to the future, but also the duality of the critique of the field in the midst of exciting and significant progress in our knowledge and understanding of leadership in schools. In the first section of the book (Chapters 2, 3 and 4), the authors examine the interplay of educational leadership research and theory as it relates to reform in schools, especially as it relates to serving historically underserved populations globally. In section 2 (Chapters 5 and 6), the authors highlight the importance of methodological considerations in school leadership research as a means to understand theory and practice as well as providing interesting avenues that point to multiple exciting future possibilities through relying on current innovations noted within the chapters. Section 3, (Chapters 7 and 8) examine the research and practice of school leadership preparation, especially as it relates to university-district partnerships and non-traditional school settings. And in the final chapter, (Chapter 9), our capstone contributor provides a means to link the present volume with the past writings on these topics, while also providing a lens to view the exciting possibilities and promises of the multiple futures of the field of educational leadership research and practice

Analysis of data from the Voyager Plasma Science Experiment using the full cup response

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1983.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCEVita.Bibliography: leaf 93.by Alan Seth Barnett.Ph.D

Considering the Use of Data by School Leaders for Decision Making: An Introduction

Our fifth book in the International Research on School Leadership series focuses on the use of data in schools and districts as useful information for leadership and decision making. Schools are awash in data and information, from test scores, to grades, to discipline reports, and attendance as just a short list of student information sources (Bernhardt, 2004), while additional streams of data feed into schools and districts from teachers and parents as well as local, regional and national policy levels (Henig, 2012; Honig & Venkateswaran, 2012; Piety, 2013). To deal with the data, schools have implemented a variety of data practices, from data rooms, to data days, data walks, and data protocols (Mandinach & Gummer, 2013; Marsh, 2012). However, despite the flood of data, successful school leaders are leveraging an analysis of their school’s data as a means to bring about continuous improvement in an effort to improve instruction for all students (Boudett & Steele, 2007). Nevertheless, some drown, some swim, while others find success. Our goal in this book volume was to bring together a set of chapters by authors who examine successful data use as it relates to leadership and school improvement. In particular, the chapters in this volume consider important issues in this domain, including: - How do educational leaders use data to inform their practice? - What types of data and data analysis are most useful to successful school leaders? - To what extent are data driven and data informed practices helping school leaders positively change instructional practice? - In what ways does good data collection and analysis feed into successful continuous improvement and holistic systems thinking? - How have school leadership practices changed as more data and data analysis techniques have become available? - What are the major obstacles facing school leaders when using data for decision making and how do they overcome them