Study of Membrane Reflector Technology

Very large reflective surfaces are required by future spacecraft for such purposes as solar energy collection, antenna surfaces, thermal control, attitude and orbit control with solar pressure, and solar sailing. The performance benefits in large membrane reflector systems, which may be derived from an advancement of this film and related structures technology, are identified and qualified. The results of the study are reported and summarized. Detailed technical discussions of various aspects of the study are included in several separate technical notes which are referenced

A study of structural concepts for ultralightweight spacecraft

Structural concepts for ultralightweight spacecraft were studied. Concepts for ultralightweight space structures were identified and the validity of heir potential application in advanced spacecraft was assessed. The following topics were investigated: (1) membrane wrinkling under pretensioning; (2) load-carrying capability of pressurized tubes; (3) equilibrium of a precompressed rim; (4) design of an inflated reflector spacecraft; (5) general instability of a rim; and (6) structural analysis of a pressurized isotensoid column. The design approaches for a paraboloidal reflector spacecraft included a spin-stiffened design, both inflated and truss central columns, and to include both deep truss and rim-stiffened geodesic designs. The spinning spacecraft analysis is included, and the two truss designs are covered. The performances of four different approaches to the structural design of a paraboloidal reflector spacecraft are compared. The spinning and inflated configurations result in very low total masses and some concerns about their performance due to unresolved questions about dynamic stability and lifetimes, respectively

The Radiographer's Role in DXA: Sports medicine and MSK

This is the author accepted manuscript. The final version is freely available from the European Society of Radiology via the link in this recor

Conceptual design studies for large free-flying solar-reflector spacecraft

The 1 km diameter reflecting film surface is supported by a lightweight structure which may be automatically deployed after launch in the Space Shuttle. A twin rotor, control moment gyroscope, with deployable rotors, is included as a primary control actuator. The vehicle has a total specific mass of less than 12 g/sq m including allowances for all required subsystems. The structural elements were sized to accommodate the loads of a typical SOLARES type mission where a swam of these free flying satellites is employed to concentrate sunlight on a number of energy conversion stations on the ground

Contemporary drama Europe: constellations of collective affiliations:"Sweet Home Europa" by Davide Carnevali and "Wir sind keine Barbaren!" by Philipp Löhle

Die vielfältigen Bedeutungen des Wortes ‚Europa‘ – Kontinent, Staatenbündnis, mythologische Figur, Kulturgut - erschweren einen genauen Bestimmungsversuches dieses Gegenstandes. Die literaturwissenschaftliche Perspektive dieser Arbeit begreift ‚Europa‘ als Konstellation kollektiver Zugehörigkeiten, deren Darstellungsform sich über Selbstbilder, Vorstellungen über das Eigene und Andere generieren. Untersucht werden zwei zeitgenössische und im Jahr 2015 häufig inszenierte Dramen, „Sweet Home Europa“ von Davide Carnevali (2009) und „Wir sind keine Barbaren!“ von Philipp Löhle (2014), und damit theatrale Texte, die ihre Performativität stets mitdenken: Das Europa, das die Textarbeit analysiert, ist nichts Prädiskursives, sondern muss kontinuierlich aufgeführt werden. Über die thematischen Cluster Ökonomie, Migration, Zivilisation, Wohlstand und Nation wird Europa als fragiles und angreifbares Konzept kollektiver Zugehörigkeiten erschließbar.There is a variety of meanings in the word “Europe” – a continent, a confederation of states, a mythological figure, a cultural asset. Thus, there is a difficulty in giving an exact definition of this word. From the literary perspective of this thesis, Europe can be regarded as a construct of great correspondence between affiliations, which are generated through the perception of the self and others. This thesis elaborates two plays that have been performed recently Sweet Home Europa by Davide Carnevali (2009) and Wir sind keine Barbaren! by Philipp Löhle (2014). The Europe that is analyzed in this thesis is based on a poststructuralist conceptualisation that sees identities not as prediscursively existing and but as discursively constructed and therefore contextually fluid. Through the cluster economy, immigration, wealth, and civilization, Europa will be revealed as a fragile and even sometimes negotiable construct of great correspondence between affiliations

Large diameter astromast development, phase 1

Coilable-longeron lattice columns called Astromasts (trademark) were manufactured for a variety of spacecraft missions. These flight structures varied in diameter from 0.2 to 0.5 meter (9 to 19 in.), and the longest Astromast of this type deploys to a length of 30 meters (100 feet). A double-laced diagonal Astromast design referred to as the Supermast (trademark) which, because it has shorter baylengths than an Astromast, is approximately four times as strong. The longeron cross section and composite material selection for these structures are limited by the maximum strain associated with stowage and deployment. As a result, future requirements for deployable columns with high stiffness and strength require the development of both structures in larger diameters. The design, development, and manufacture of a 6.1-m-long (20-ft), 0.75-m-diameter (30-in.), double-laced diagonal version of the Astromast is described

Evaluation of Pavement Markings on Low-Volume Rural Roadways in Iowa

Many rural roadways in Iowa have centerline and/or edgeline pavement markings. The current Manual on Uniform Traffic Control Devices (MUTCD), however, requires centerline and/or edgeline pavement markings only along streets and roadways with traffic volumes much greater than 400 vehicles per day (the volume-based definition of a low-volume roadway in the MUTCD). This project was initiated to gather and summarize information about the state of practice related to the installation and maintenance of pavement markings along low-volume rural roadways in Iowa. Additional information was also collected to provide more guidance in the pavement-marking decision-making process. The tasks completed include an examination and summary of past research, the collection of legal input related to the use of pavement markings in Iowa, and a survey of Iowa county engineers that focused on their current pavement-marking practices. A basic safety benefit-cost evaluation of pavementmarking applications was also performed. Overall, the literature on the effectiveness of pavement markings and their safety impacts is limited. A number of studies have been completed with varying levels of robustness and reliability in their results. The Highway Safety Manual includes crash modification factors for the installation of centerline markings that it indicates should be used with caution, and one for the installation of edgeline and centerline markings that equates to a 24 percent total serious and minor-injury crash reduction. A more recent study from Louisiana also found a 15 percent reduction in total crashes after the addition of edgelines. The legal input acquired as part of this project was generally common knowledge. It indicated that once a traffic control device has been installed, the jurisdiction must properly and adequately maintain it. The survey completed found that, of the great majority of the respondents (97 percent), painted centerline/no passing zones and edgelines on at least some of their paved low-volume rural roadways. A much smaller percentage took this approach, or just painted centerlines/no passing zones, along their seal-coated roadways. The basic cost-benefit evaluation found that the percentage of crash reduction needed from pavement markings to make them beneficial was very low (i.e., 5.1 percent, at most). Overall, it was concluded that pavement markings are widely used in Iowa along low-volume paved roadways and sometimes seal-coated roadways. In addition, there is a safety benefit to the installation of pavement markings. but the research into that impact is limited, particularly along low-volume roadways. It is recommended that further analysis be completed on potential pavement-marking safety impacts, that a pavement-marking database be developed, and that a committee be initiated to help develop policies related to pavement-marking removal

Women in the 1929 Textile Strikes in Elizabethton, Tennessee and Gastonia, North Carolina

In southern labor history the role of women remains one of the most overlooked and misconstrued. Most works on the subject have relegated women to support roles within the labor movement or designated those who stood out as wild women. Through the use of existing works on the topic, interviews with strikers and witnesses, and contemporary newspaper articles, this thesis will show, in two case studies, of Elizabethton, Tennessee, and Gastonia, North Carolina, that women involved in the 1929 strikes were neither merely supporters nor wild women. They were instead the public faces of the textile labor movement and took major roles in the leadership, organization and course of their respective strikes. Like women before them, in the suffragist movement, and the early women’s labor movements in Lowell, Massachusetts and other northern mills, they acted at the confluence of competing forces and demands. Often characterized in the newspapers and popular mindset as mothers striking for better wages for their families and for better conditions, they couched their militancy in the language of motherhood, garnering public support for their unions and rousing outrage at the mistreatment directed toward them. The women in Elizabethton and Gastonia merged the new woman of the 1920s and the Victorian ideals of motherhood. Their fight reflected the tensions surrounding gender and labor which had arisen in the economic and cultural struggles of the 1920s South