Analysis of separation of the space shuttle orbiter from a large transport airplane

The feasibility of safely separating the space shuttle orbiter (140A/B) from the top of a large carrier vehicle (the C-5 airplane) at subsonic speeds was investigated. The longitudinal equations of motion for both vehicles were numerically integrated using a digital computer program which incorporates experimentally derived interference aerodynamic data to analyze the separation maneuver for various initial conditions. Separation of the space shuttle orbiter from a carrier vehicle was feasible for a range of dynamic-pressure and flight-path-angle conditions. By using an autopilot, the vehicle attitudes were held constant which ensured separation. Carrier-vehicle engine thrust, landing gear, and spoilers provide some flexibility in the separation maneuver

The Aerospace Vehicle Interactive Design system

The aerospace vehicle interactive design (AVID) is a computer aided design that was developed for the conceptual and preliminary design of aerospace vehicles. The AVID system evolved from the application of several design approaches in an advanced concepts environment in which both mission requirements and vehicle configurations are continually changing. The basic AVID software facilitates the integration of independent analysis programs into a design system where the programs can be executed individually for analysis or executed in groups for design iterations and parametric studies. Programs integrated into an AVID system for launch vehicle design include geometry, aerodynamics, propulsion, flight performance, mass properties, and economics

Government Response to Drought in the United States: With Particular Reference to the Great Plains

Drought relief has become an expected response of the federal government to periods of widespread drought in the United States. A wide range of emergency, short-term and long-term drought programs were formulated to deal with the extreme drought of the 1930\u27s. By 1977 there were 40 separate programs administered by 16 different federal agencies. This paper traces the development of federal drought relief bureaucracy, including drought designation criteria and procedures. Two obvious deficiencies of past drought relief efforts in the United States are noted. First, drought relief organizations and programs have been hastily assembled during periods of crisis. This has resulted in reduced program effectiveness as implementation has often been delayed pending program formulation and congressional approval. Second, previous efforts have had no adequate and systematic provision of timely information on drought conditions and impacts to persons or agencies involved in administering drought programs. The design, implementation and evaluation of a near real-time drought surveillance and early warning system is mentioned as one way atmospheric scientists can contribute to improved drought response in the United States

From the Director: Fall 2000

The NDMC hosted the first annual “Drought Monitor Forum” in November. Most of the readers of Drought Network News are probably aware of the Drought Monitor web site (http://enso.unl.edu/ monitor/index.html) and the products that are provided to users. (Mark Svoboda of the NDMC provided an overview of the Drought Monitor product in the Winter/Spring 2000 issue of Drought Network News.) This weekly product, jointly produced by the NDMC, U.S. Department of Agriculture, and NOAA’s Climate Prediction Center, has been widely accepted in the United States, and other countries are considering the adoption of a similar technique for mapping drought occurrence and classifying severity levels. The web site receives about 30,000 hits a week and is published widely in newspapers across the country. It has also been adopted by The Weather Channel. A diverse set of users and technical specialists came together to review the product’s successes and failures during its first year. We also discussed some of the more technical aspects of product development such as nomenclature and the use or modification of climate indices for incorporation in a blended index. Expect to see changes in the product, some subtle and some more dramatic, in the months ahead. We also expect NOAA’s National Climatic Data Center to join us as a new partner in this activity in the spring of 2001. The Drought Monitor was highlighted in the report of the National Drought Policy Commission (NDPC) to Congress and the President in May 2000, and the NDPC recommended continued and expanded support for this partnership effort. (The NDPC report can be found at http://www.fsa.usda.gov/drought/finalreport/accesstoreports.htm.

Western Drought Coordination Council: Frequently Asked Questions

Contents: What is the Western Drought Coordination Council (WDCC)? What does the WDCC hope to accomplish? What prompted the formation of the Council? Preparedness and Mitigation Monitoring, Assessment, and Prediction Response Communications To Whom does the WDCC report? How do I get in touch with the Council

CHANGING FIELDS: AGRICULTURAL LAND USE CHANGES IN NEBRASKA 1925-1974

The series of graphs and maps which follow illustrate agricultural land use changes in Nebraska from 1925 to 1974. With these graphs and maps, the major agronomic crops of corn (dryland and irrigated), wheat, sorghum and soybeans are analyzed. The purpose of this analysis is to provide a pictorial history of Nebraska\u27s ever-changing cropping system and, hopefully, to stimulate ideas and discussion with regard to trends and future directions. The Nebraska Water Resources Center is deeply interested in both the past and the future of Nebraska\u27s agriculture because of the demands which agriculture places on the state\u27s water resources. An examination of the maps showing land use changes within counties across the state will reveal not only the ever-growing magnitude of this demand, but also its evolving spatial characteristics. In 1925 crop production in Nebraska was almost exclusively dryland, and corn was the primary crop. Although corn is still our primary crop, irrigation has greatly altered the nature of its geographic importance. Additionally, alterations in the pattern of wheat acreages and the introduction of sorghum and soybeans have modified and diversified Nebraska\u27s crop production system. From the above, one can conclude that Nebraska\u27s water resources are being utilized far differently today than in the past. Because demands are increasing and our water resources finite, it is easy to understand the growing conflicts among users. The Water Resources Center hopes that the information presented in this publication will broaden our comprehension of the past and thereby assist in a better understanding of future issues and the conflicts which may confront us

The impact of alcohol and drug use on employment: A labor market study using the National Longitudinal Survey of Youth

The purpose of this study was, first, to estimate of the impact of alcohol and drug use on the employment status of men and women, and second, to examine whether a history of past use, as opposed to current use, adversely affects the propensity to be employed. Using data from the National Longitudinal Survey of Youth we conducted a cross-sectional and a longitudinal analysis with logistic regression estimation to model the probability that a person was employed in 1992. In addition to usual regressors, interactions between substance use measures, between substance use measures and human capital variables, and between substance use measures and race dummies were included in the equation. The longitudinal analysis utilized a conditional likelihood method based on employment data in 1992 and 1988 and included the difference between 1992 regressors and their 1988 counterparts. A comparison was made between the prediction accuracy of the logit choice model, linear discriminant analysis, k-nearest neighbor analysis, and three modern classification methods that are used extensively in the area of machine learning. Results showed that the logit model performs relatively well in classifying individuals into employed and unemployed categories based on individual attributes. Results of the cross-sectional and longitudinal analysis were mixed, but not inconsistent with our prior expectations that use of alcohol or drug has a negative impact on a person's propensity to be employed. Cross-sectional results show a clear negative impact of past substance use on a person's employment probability among all demographic groups examined (by gender: all persons, blacks, Hispanics, families with income below the poverty line, and high users of alcohol or drugs). However, when current and past use are considered together, only women seem to experience negative impacts. The results of the longitudinal analysis are less clear, although they do indicate that negative impacts are associated with the interaction between substance use measures and human capital variables. Limitations of the study are pointed out and suggestions are made for future research.

From the Director: February 1998

If it seems like considerable time has elapsed since you received the last issue of Drought Network News, it is not just your imagination. After much discussion, we decided not to publish the newsletter in October 1997. First, we had a limited number of submissions to include. Second, the task of editing the manuscript for a new drought book was an overwhelming task that was involving much of my time and that of my publications specialist, Deborah Wood. She is also responsible for Drought Network News. With more submissions and the near completion of the drought book, I am pleased to be publishing this issue of the newsletter. The National Drought Mitigation Center (NDMC) organized and conducted two training workshops on drought contingency planning in 1997. These workshops were very successful, with more than 200 participants representing a diverse background of tribal, local, state, federal, and regional organizations and agencies. Three more workshops are planned for this spring. An article about the workshops is included in this issue (p. 3). The National Drought Policy Act continues to be discussed in the U.S. Congress. The Senate version of the bill (S222) passed last November. An identical version of the bill was introduced in the House of Representatives (HR3035) in November. I testified in support of the bill at a hearing in late January. Although some minor modifications may be made in the bill, it is expected to pass the House. This bill would establish a commission to review existing drought programs at the federal, state, and local level and make recommendations to the Congress and the president on the elements of a national drought policy. The commission would have 18 months to complete its task. The NDMC will work closely with the commission

From the Director: Fall 2000

The NDMC hosted the first annual “Drought Monitor Forum” in November. Most of the readers of Drought Network News are probably aware of the Drought Monitor web site (http://enso.unl.edu/ monitor/index.html) and the products that are provided to users. (Mark Svoboda of the NDMC provided an overview of the Drought Monitor product in the Winter/Spring 2000 issue of Drought Network News.) This weekly product, jointly produced by the NDMC, U.S. Department of Agriculture, and NOAA’s Climate Prediction Center, has been widely accepted in the United States, and other countries are considering the adoption of a similar technique for mapping drought occurrence and classifying severity levels. The web site receives about 30,000 hits a week and is published widely in newspapers across the country. It has also been adopted by The Weather Channel. A diverse set of users and technical specialists came together to review the product’s successes and failures during its first year. We also discussed some of the more technical aspects of product development such as nomenclature and the use or modification of climate indices for incorporation in a blended index. Expect to see changes in the product, some subtle and some more dramatic, in the months ahead. We also expect NOAA’s National Climatic Data Center to join us as a new partner in this activity in the spring of 2001. The Drought Monitor was highlighted in the report of the National Drought Policy Commission (NDPC) to Congress and the President in May 2000, and the NDPC recommended continued and expanded support for this partnership effort. (The NDPC report can be found at http://www.fsa.usda.gov/drought/finalreport/accesstoreports.htm.

Series Preface — Drought and Water Crises

Drought is a normal part of the climate for virtually all climatic regimes. It is a complex, slow-onset phenomenon that affects more people than any other natural hazard and results in serious economic, social, and environmental impacts. Drought affects both developing and developed countries, but in substantially different ways. Society’s ability to manage droughts more effectively in the future is contingent upon a paradigm shift—moving from a crisis management to a risk-based management approach directed at increasing the coping capacity or resilience of nations to deal effectively with extended periods of water shortage. In 2005, I edited a book for CRC Press, Drought and Water Crises: Science, Technology, and Management Issues. The goal of this book series is to expand on the theme of the 2005 book by providing new information and innovative approaches to drought monitoring and early warning systems, mitigation, planning, and policy and the linkages between these challenges and important natural resources and environmental issues such as climate change, including increased climate variability, water scarcity, food security, desertification, transboundary water-related conflicts, and water management, to name just a few. There is an increasing demand for more information from scientists, natural resource managers, and policy makers on issues related to these challenges that are at the intersection of drought and water management issues as pressure on the world’s finite water resources intensifies