An analytical optimization of electric propulsion orbit transfer vehicles

Due to the electric propulsion's inherent propellant mass savings over chemical propulsion, electric propulsion orbit transfer vehicles (EPOTV's) are highly efficient mode of orbit transfer. When selecting an electric propulsion device (ion, MPD, or arcjet) and propellant for a particular mission, it is preferable to use quick, analytical system optimization methods instead of time intensive numerical integration methods. It is also of interest to determine each thruster's optimal operating characteristics for a specific mission. Analytical expressions are derived which determine the optimal specific impulse (Isp) for each type of electric thruster to maximize payload fraction for a desired thrusting time. These expressions take into account the variation of thruster efficiency with specific impulse. Verification of the method is made with representative electric propulsion values on a LEO-to-GEO mission. Application of the method to specific missions is discussed

Controlled Ecological Life Support Systems (CELSS) conceptual design option study

Results are given of a study to explore options for the development of a Controlled Ecological Life Support System (CELSS) for a future Space Station. In addition, study results will benefit the design of other facilities such as the Life Sciences Research Facility, a ground-based CELSS demonstrator, and will be useful in planning longer range missions such as a lunar base or manned Mars mission. The objectives were to develop weight and cost estimates for one CELSS module selected from a set of preliminary plant growth unit (PGU) design options. Eleven Space Station CELSS module conceptual PGU designs were reviewed, components and subsystems identified and a sensitivity analysis performed. Areas where insufficient data is available were identified and divided into the categories of biological research, engineering research, and technology development. Topics which receive significant attention are lighting systems for the PGU, the use of automation within the CELSS system, and electric power requirements. Other areas examined include plant harvesting and processing, crop mix analysis, air circulation and atmosphere contaminant flow subsystems, thermal control considerations, utility routing including accessibility and maintenance, and nutrient subsystem design

Combined high and low thrust propulsion for fast piloted Mars missions

The mission benefits of using both high thrust nuclear thermal propulsion (NTP) and low acceleration, high specific impulse nuclear electric propulsion (NEP) to reduce piloted trip times to Mars with reasonable initial mass are assessed. Recent updates in mission design, such as the Earth fly-by return, are assessed for their impact on previous studies. In addition, the Synthesis Commission split mission to Mars in 2014 is also assessed using combined propulsion. Results show an 80 to 100 day reduction in trip time over the reference NTP or NEP systems and missions, with comparable or reduced vehicle initial masses. The impacts of the mission and system analyses upon technology planning and design are discussed

Gladys Rosson

Gladys Rosson was Cecil B. DeMille’s secretary for thirty-nine years, starting the summer she graduated high school in 1914 until her death in 1953 (DeMille and Hayne 1959, 95). She was also his mistress, part of his “harem,” or, as DeMille’s niece Agnes, calls it, his “seraglio”—the members of which vary according to sources (Agnes deMille 1990, 183). Regardless, she was intimately involved in DeMille’s work, ranging from the production of his films to the investment of his finances to the management of his image. If ever there was a woman behind the man, Gladys was she

Student Credit Card Debt in the 21st Century: Options for Financial Aid Administrators

Credit card debt and other financial problems permeate student life. The financial literature suggests that the severity of student credit problems are not only more intense than previously thought-indeed, they appear to be worsening with time. Although lack of financial education has been targeted as the culprit by most observers, to date the bulk of financial curriculum has been developed for younger groups and has neglected the college-age audience. This article provides multiple workable solutions financial aid offices can offer students throughout their college experience: preventive solutions for avoiding problems with credit card debt, holistic solutions for ((other related problems, and remedial solutions for existing problems. Many of the suggestions point to a possible reevaluation and redefinition of the traditional role of the financial aid administrator

The Evolution of Grain Trading Organizations in Australia: Applying the Cooperative Life Cycle

Cook’s (1995) life cycle theory of cooperatives predicts a rise and fall of cooperatives over time. He argues that cooperatives arise as a response, by producers or consumers, to some form of inefficiency in a market structure, for example an oligopoly. In such a market, the cooperative can thrive by replacing the ineffective firms until other firms or institutions or technology come along and deliver even better service. When this happens, the cooperative’s ownership and control features may hamper its ability to grow and compete. According to Cook, the cooperative will eventually need to change in order to accommodate investors, or it will be forced to exit the market. This article considers the case of Australia’s grain market within Cook’s framework to see if it has behaved as predicted and where it is heading in terms of responding to the needs of the agents in the market chain. In the 1980s Australia’s grain cooperatives and institutions faced challenges from deregulation and changing market structure that exposed extensive inefficiency in the traditional cooperative ownership arrangements. This article will review the origins, successes and eventual transformation of Australia’s major grain marketing institutions.Agribusiness,

Corn Rootworm Insecticide Performance

The objective of our testing program is to monitor the performance of registered insecticides and evaluate new chemical and transgenic tools that are more economical, efficacious, and environmentally compatible. Labeled corn rootworm insecticides are evaluated yearly on university research farms and the farms of private growers. 2000 data from the Crawfordsville SE Research Farm, a 2000 summary, and a 3-year summary are presented in this report

Vaudevival: Old is the new New

Vaudevival: Old is the new New was an evening-length concert performed October 20th & 21st, 2011 at the Clarice Smith Performing Arts Center in partial fulfillment of the M.F.A. degree in Dance from the University of Maryland's School of Theatre, Dance, and Performance Studies. Vaudevival was a "trad" dance theater project that challenged concepts of aesthetic hierarchies in popular culture. The show ricocheted through twentieth-century vernacular dance to create a vibrant statement about the cyclical nature of art and society, with live music and multi-media projections. This paper is a written account of theoretical and practical problems of identity politics and appropriation that unfolded during the choreographic process. Envisioning a creative utopia free of exploitative hierarchies - both on the stage and on the page, Vaudevival invokes the old to reinvent the new through the intertextuality of American dances, bringing scholarship to the theater, and bringing some theater to scholarship

A Historical Development of Pooling of Interest

The term pooling of interests was first used by the AI CPA in a report issued in 1945 by the Committee on Public Utility Accounting. Since that time, the pooling of interests concept went through much debated change and revision The Accounting Principles Board issued their first opinion on pooling of interests in Accounting Research Bulletin Forty. This bulletin was followed by three more. During this time the criteria proposed in these bulletins as a basis for classifying a business combination as a pooling of interests were being constantly modified. Many of the changes began to liberalize the accounting treatment of a business combination. It finally reached the point where many of the guidelines set down by the AICPA were being ignored in actual practice. After reviewing the situation the Accounting Principles Board decided there was a definite need to clarify the distinction between a pooling of interests and a purchase. Finally, in 1970 the Board issued Opinion Sixteen This paper will review the pronouncements issued by the Accounting Principles Board concerning pooling from 195 O to the issuance of Opinion Sixteen. It will also analyze the change in application of pooling and the environment of pooling from 1950 to the present. Finally, it will discuss the need for and the recommendations of Opinion Sixteen issued in October, 197