1,161 research outputs found
Development of a meteoroid penetration distributed transducer Third quarterly report
Impact calibration tests in development of meteoroid penetration distributed transduce
Theoretical and experimental study of twisted and cambered delta wings designed for a Mach number of 3.5
Data are provided for the evaluation of the aerodynamic performance of a series of twisted and cambered delta wings designed for a Mach number of 3.5. Systematic force and pressure data are also presented for comparison with theory. Force tests were made at Mach numbers of 2.3, 3.0, 3.5, 4.0, and 4.6. Design lift coefficients of 0.0 and 0.1 were employed on the 55 deg and 68 deg sweep wings, and design lift coefficients of 0.0, 0.05, and 0.1 were employed on the 76 deg sweep wings. Pressure tests were conducted on the 55 deg and 76 deg sweep flat wings and on the 0.1 design lift coefficient 76 deg sweep wing. The results indicate that for the sweep angles tested, an increase in the zero-lift pitching-moment coefficient is the primary benefit of twist and camber at a Mach number of 3.5. Comparison of the experimental results with results obtained from several lift theories indicates that the Carlson-Middleton linear theory method gave the best overall agreement. The pressure data indicate, however, that there is a cancellation of error at high angle of attack where the lower surface pressures are significantly underpredicted over the inboard region of the wing and where the upper and lower surface pressures are overpredicted over the outboard region of the wing
FORVAL-Online: A Web-based forestry investment tool
Over the past decade, timber values have risen considerably, and society is beginning to see timberland for what it is – a valuable capital asset that must be managed properly. Timberlands, however, cannot be subject to an “across the board” management regime. Different sites possess different productive constraints, and the same holds true for landowners and their management goals. Considering the diversity of managers’ and landowners’ analysis needs, the ability to obtain a customized forestry investment analysis is invaluable. “FORVAL-online: A Web-based Forestry Investment Tool” is a project to develop and make widely available an accurate and easy to use forestry investment analysis package for use by non-industrial private forest landowners and forestry professionals. FORVAL-online accepts user input and performs calculations in the following areas: financial criteria, monthly payments, annual payments, precommercial timber value and projected stumpage price
The Economic Impacts of the Tobacco Settlement
Recent litigation against major tobacco companies culminated in a Master Settlement Agreement' (MSA) under which the participating companies agreed to compensate most states for Medicaid expenses. We outline the terms of the settlement and analyze whether it was a move toward economic efficiency using data from Massachusetts. Medicaid spending will fall, but only a modest amount ($0.1 billion). The efficiency issue turns mainly on the treatment of health benefits from reduced smoking induced by the settlement. We conclude that the settlement was a move towards economic efficiency.
Low-Cost Flow Visualization for a Supersonic Ejector
Shadowgraph techniques were applied to the cold flow ejector facility at the Propulsion Research Center at the University of Alabama in Huntsville. The setup for the experiments was relatively simple and was accomplished at very little cost. Series of shadowgraph images were taken of both dual nozzle and single nozzle strut based ejectors operating over a range of chamber pressures. The density gradient patterns in the shadowgraphs were compared to pressure data measured along the top and side walls of the mixing duct. The shadowgraph images showed the presence of barrel shocks emanating from the nozzles which at low pressures terminated in Mach disks and at higher pressures extended beyond the barrel shape and reflected off the walls of the duct. Based on pressure data from previous testing, reflected shocks were expected on the walls of the duct. The shadowgraph images confirmed the locations of these reflected shocks on the top wall of the duct. The shadowgraph images also showed the structure change which correlated to a change in pitch of the ejector noise, and corresponded to a change in trend of the duct wall pressure ratio distributions. The images produced from the setup provided insight into the complex flow behavior inside the ejector duct. In addition, the techniques were a valuable tool as an educational device for students
Some biological aspects of fish culture in the middle Rio Grande conservancy drains.
The purpose of this investigation is to determine the adaptability of the Middle Rio Grande conservancy drains to fish culture. The Albuquerque Riverside Drain has been selected for this study because it is a typical conservancy drain. The section investigated extends a distance of nine miles from a point one mile above the Barelas bridge at a point due west of Alameda
Toward the Understanding of Organizational Flexibility
Contingency planning is widely touted as a method of preparing for and confronting disruptions to organizational activity; its attributes are proposed to promote organizational flexibility. This study examines the relationship between information sharing, internal and external collaboration, and information technology use and organizational flexibility and develops a model that will provide both academicians and practitioners with a means of determining the attributes with the highest relationship to organizational flexibility. This knowledge will allow for prioritization of resources in the planning process. A survey of 50 professionals from various sectors of the government is used to test the hypotheses developed
Numerical simulation of film-cooled ablative rocket nozzles
The objective of this research effort was to evaluate the impact of incorporating an additional cooling port downstream between the injector and nozzle throat in the NASA Fast Track chamber. A numerical model of the chamber was developed for the analysis. The analysis did not model ablation but instead correlated the initial ablation rate with the initial nozzle wall temperature distribution. The results of this study provide guidance in the development of a potentially lighter, second generation ablative rocket nozzle which maintains desired performance levels
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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