Condensation on spacecraft surfaces downstream of a Kaufman thruster

Thruster exhaust products condensation on surfaces downstream of mercury electron bombardment ion thruste

High-Vacuum Condenser Design: Experimental Effects from Cesium and Mercury Ion Beams

Effects of variable-energy electrostatic rocket-engine ion exhaust beams that pertain to the design of high-vacuum condensers are discussed. Three ion-engine beam sources, using cesium and mercury as propellants, were operated at energy levels of 200 to 9000 electron volts and currents of 0.002 to 0.200 ampere. Five condenser geometries, having surface areas from 0.287 to 5.76 square meters, were tested. Values for a function of the accommodation and condensation coefficients, which appears in an existing theoretical analysis, were determined. Although exhibiting rather wide variations in some tests, the values were estimated at approximately 0.15 for cesium and 0.015 for mercury. A method of estimating condenser surface area requirements is given

Numerical solutions of free-molecule flow in converging and diverging tubes and slots

Numerical solutions of free molecular flow in converging and diverging tubes and slot

Rocket engine Patent

Metal ion rocket engine desig

Urban Trail System Planning in the Western United States: An Analysis of the Trail-Specific Planning Efforts of Four Cities that Have Implemented Urban Trail Systems

States in the Western United States are growing at rates outpacing the rest of the nation. This growth is placing pressure on communities to develop their current open space for residential or commercial use. As cities develop a comprehensive open space plans, several elements arise. One critical element is connectivity. This connectivity is most often realized in the form of greenways. In many cities these greenways contain urban trail systems that provide significant recreation and connectivity benefits. This thesis investigates the current recommended models used to plan for greenway, synthesizes them into a recommended model process, and analyzes case studies of four cities that have implemented urban trail systems against this model framework. The case studies include cities in the West with populations between 50,000 and 100,000 that are not part of a greater metropolitan area with demonstrated planning and implementation of urban trail systems. This selection provides the most relevance to smaller cities in the West that are beginning open space planning efforts. Developing a recommended model process will aid smaller communities in planning for greenways by providing a step-by-step process from concept to implementation. This guide can provide a roadmap for communities that do not have experience with these planning models and can be used by citizens and non-planning professionals as well. Three critical factors arose that were common to all case studies. First, the need to follow a trail-specific planning process. The communities studied had all made efforts to plan for trails apart from their general or comprehensive plans. Second, the planning process must have a robust public participation process. This ensures that community needs are met and buy-in is achieved for the implementation process. Lastly, the early identification of trail corridors is essential to the long-term planning process. This ensures that there are no surprises for the community when implementation begins. These factors should receive particular attention from communities wishing to develop urban trail systems

Accurate measurement and assessment of the QT interval

QT measurement should be included as part of the systematic interpretation of the electrocardiogram (ECG). Accurate measurement and interpretation of the QT interval will help to identify potentially fatal long QT syndrome (LQTS). The assessment of the QT interval, correction of the QT and the guidelines relating to it are complex. This article discusses the importance of this element of the ECG and offers practical advice on QT assessment based on a review of the relevant literature. </jats:p

Anonimo Mexicano

Transcribed from the original Nahuatl manuscript (written circa 1600) and translated into English for the first time, this epic chronicle tells the preconquest history of the Tlaxcalteca, who migrated into central Mexico from the northern frontier of the Toltec empire at its fall. By the time of Cortés\u27s arrival in the sixteenth century, the Tlaxcalteca were the main rivals to the Mexica, or Aztecs, as they are commonly known. One of the few peoples of central Mexico not ruled from the Mexica capital city of Tenochtitlan, the Tlaxcalteca resided in the next valley to the east and became Cortés\u27s powerful allies. They were also speakers of the Nahuatl language who followed a sophisticated agriculturally based urban way of life and documented their history in traditional —painted books —created by specially trained scribes. Thus, their chronicle, Anónimo Mexicano, offers a rare alternative perspective on the history of central Mexico, which has been dominated in the popular imagination by the stories of the Mexica. The original Anónimo Mexicano is housed in the Bibliotheque Nationale de Paris. Its first complete publication here includes a full English translation, the original classical Nahuatl, a modern Nahuatl version, and comprehensive annotation. This definitive edition thus will be valuable for linguists, ethnohistorians, folklorists, Mesoamerican scholars, and others. Moreover, anyone interested in the epic origin tales of peoples and nations will find interest in Anónimo Mexicano\u27s grand narrative of dynastic wars, conquests, and migrations, cast in mythological terms.https://digitalcommons.usu.edu/usupress_pubs/1014/thumbnail.jp

Flux patterns resulting from free-molecule flow through converting and diverging slots

Flux patterns from free molecular gas flow through converging and diverging slot