An Introduction to Pure Spinor Superstring Theory

In these lecture notes presented at the 2015 Villa de Leyva Summer School, we give an introduction to superstring theory. We begin by studying the particle and superparticle in order to get a better understanding on the superstring side. Afterwards, we review the pure spinor formalism and end by computing the scattering amplitude for three gravitons at tree-level.Comment: Villa de Leyva Summer School 2015 proceedings, 28 pages, 2 figure

Phrasal Alternation in the Pondok Tinggi Dialect of Kerinci; an Intergenerational Analysis

This paper examines the implications of language contact in a Malay sub-variety known as Pondok Tinggi, spoken in Sumatra. My focus is on the grammatical phenomenon of phrasal alternation. Phrasal alternation is characterized by the presence of two distinct forms for nearly all lexical items, whose final syllables differ in shape. These are termed absolute and oblique (Steinhauer and Usman 1978: 485). The intergenerational transmission of this uncommon feature offers a way to measure the degree of contact-induced language change in Pondok Tinggi. An experiment was conducted to elicit the USAge of the absolute and the oblique forms in order to find out how the distribution of phrasal alternation has changed within the last two generations. I reveal a grammatical simplification caused by contact between Pondok Tinggi and Bahasa Indonesia, a related Malayic variety serving as Indonesia's prestigious official language. This adds a dimension of loss of local linguistic diversity to more familiar tropes of the national success of Bahasa Indonesia

Simultaneous processing of vibration test data

Data from record tracks of all accelerometers is injected simultaneously into electronic circuits which convert inputs into single, composite graphical representation. Three adequate methods of processing data: peak acceleration at a frequency, average of all channels, and quad-mean of all channels

Aerodynamic forces of fluttering cylindrical and/or planar structures

Complexity of the phenomena of panel flutter instability has resulted in the necessity of developing separate design criteria for a variety of flow conditions and panel configurations. Vehicle panel configurations with low aspect ratios are of interest in low supersonic flow, where boundary layer effects are important

Classical aspects of lightlike dimensional reduction

Some aspects of lightlike dimensional reduction in flat spacetime are studied with emphasis to classical applications. Among them the Galilean transformation of shadows induced by inertial frame changes is studied in detail by proving that, (i) the shadow of an object has the same shape in every orthogonal-to-light screen, (ii) if two shadows are simultaneous in an orthogonal-to-light screen then they are simultaneous in any such screen. In particular, the Galilean group in 2+1 dimensions is recognized as an exact symmetry of Nature which acts on the shadows of the events instead that on the events themselves. The group theoretical approach to lightlike dimensional reduction is used to solve the reconstruction problem of a trajectory starting from its acceleration history or from its projected (shadow) trajectory. The possibility of obtaining a Galilean projected physics starting from a Poincar\'e invariant physics is stressed through the example of relativistic collisions. In particular, it is shown that the projection of a relativistic collision between massless particles gives a non-relativistic collision in which the kinetic energy is conserved.Comment: Latex2e, 28 pages, 3 figures, uses psfra

An overview of NASA research on positive displacement general-aviation engines

The research and technology program related to improved and advanced general aviation engines is described. Current research is directed at the near-term improvement of conventional air-cooled spark-ignition piston engines and at future alternative engine systems based on all-new spark-ignition piston engines, lightweight diesels, and rotary combustion engines that show potential for meeting program goals in the midterm and long-term future. The conventional piston engine activities involve efforts on applying existing technology to improve fuel economy, investigation of key processes to permit leaner operation and reduce drag, and the development of cost effective technology to permit flight at high-altitudes where fuel economy and safety are improved. The advanced engine concepts activities include engine conceptual design studies and enabling technology efforts on the critical or key technology items

Implementing transit oriented development in Greater London

This book provides new dimensions and a contemporary focus on sustainable transport, urban regeneration and development in eight countries spanning four continents at different stages of development. It examines the role of transit oriented development (TOD) in improving urban sustainability and providing different transport choices, exploring how these can be implemented in modern cities. Establishing a new agenda for TOD, experts in the field critically evaluate the links between urban transport investment and economic, social and environmental sustainability, introducing new methods of analysis. The chapters investigate the international dimensions of TOD, providing crucial insights into issues such as uneven development, transport emissions, global warming, car dependence and the challenge of powering vehicles with sustainable fuels. Urban and regional planning, transport studies and environmental management scholars seeking to understand urban sustainability issues will benefit from this timely book. It will also prove to be a valuable read for urban planners and research consultants looking to widen their knowledge of the role of TOD in enhancing urban sustainability