Users guide: Steady-state aerodynamic-loads program for shuttle TPS tiles

A user's guide for the computer program that calculates the steady-state aerodynamic loads on the Shuttle thermal-protection tiles is presented. The main element in the program is the MITAS-II, Martin Marietta Interactive Thermal Analysis System. The MITAS-II is used to calculate the mass flow in a nine-tile model designed to simulate conditions duing a Shuttle flight. The procedures used to execute the program using the MITAS-II software are described. A list of the necessry software and data files along with a brief description of their functions is given. The format of the data file containing the surface pressure data is specified. The interpolation techniques used to calculate the pressure profile over the tile matrix are briefly described. In addition, the output from a sample run is explained. The actual output and the procedure file used to execute the program at NASA Langley Research Center on a CDC CYBER-175 are provided in the appendices

Do Employment Protections Reduce Productivity? Evidence from U.S. States

Theory predicts that mandated employment protections may reduce productivity by distorting production choices. Firms facing (non-Coasean) worker dismissal costs will curtail hiring below efficient levels and retain unproductive workers, both of which should affect productivity. These theoretical predictions have rarely been tested. We use the adoption of wrongful-discharge protections by U.S. state courts over the last three decades to evaluate the link between dismissal costs and productivity. Drawing on establishment-level data from the Annual Survey of Manufacturers and the Longitudinal Business Database, our estimates suggest that wrongful-discharge protections reduce employment flows and firm entry rates. Moreover, analysis of plant-level data provides evidence of capital deepening and a decline in total factor productivity following the introduction of wrongful-discharge protections. This last result is potentially quite important, suggesting that mandated employment protections reduce productive efficiency as theory would suggest. However, our analysis also presents some puzzles including, most significantly, evidence of strong employment growth following adoption of dismissal protections. In light of these puzzles, we read our findings as suggestive but tentative.Dismissal Costs, Employment Fluctuations, Entry and Exit, Labor Productivity, TFP, Entrepreneurship.

Do Employment Protections Reduce Productivity? Evidence from U.S. States

Theory predicts that mandated employment protections may reduce productivity by distorting production choices. Firms facing (non-Coasean) worker dismissal costs will curtail hiring below efficient levels and retain unproductive workers, both of which should affect productivity. These theoretical predictions have rarely been tested. We use the adoption of wrongful-discharge protections by U.S. state courts over the last three decades to evaluate the link between dismissal costs and productivity. Drawing on establishment-level data from the Annual Survey of Manufacturers and the Longitudinal Business Database, our estimates suggest that wrongful-discharge protections reduce employment flows and firm entry rates. Moreover, analysis of plant-level data provides evidence of capital deepening and a decline in total factor productivity following the introduction of wrongful-discharge protections. This last result is potentially quite important, suggesting that mandated employment protections reduce productive efficiency as theory would suggest. However, our analysis also presents some puzzles including, most significantly, evidence of strong employment growth following adoption of dismissal protections. In light of these puzzles, we read our findings as suggestive but tentative.

Preliminary flight evaluation of an engine performance optimization algorithm

A performance seeking control (PSC) algorithm has undergone initial flight test evaluation in subsonic operation of a PW 1128 engined F-15. This algorithm is designed to optimize the quasi-steady performance of an engine for three primary modes: (1) minimum fuel consumption; (2) minimum fan turbine inlet temperature (FTIT); and (3) maximum thrust. The flight test results have verified a thrust specific fuel consumption reduction of 1 pct., up to 100 R decreases in FTIT, and increases of as much as 12 pct. in maximum thrust. PSC technology promises to be of value in next generation tactical and transport aircraft

While The Stars In The Heavens Shine On

https://digitalcommons.library.umaine.edu/mmb-vp/4404/thumbnail.jp

Challenges of ultra large scale integration of biomedical computing systems

The NCRI Informatics Initiative is overseeing the implementation of an informatics framework for the UK cancer research community. The framework advocates an integrated multidisciplinary method of working between scientific and medical communities. Key to this process is community adoption of high quality acquisition, storage, sharing and integration of diverse data elements to improve knowledge of the causes, prevention and treatment of cancer. The integration of the complex data and meta-data used by these multiple communities is a significant challenge and there are technical, resource-based and sociological issues to be addressed. In this paper we review progress aimed at establishing the framework and outline key challenges in ultra large scale integration of biomedical computing systems

Steady internal flow and aerodynamic loads analysis of shuttle thermal protection system

An analytical model for calculation of ascent steady state tile loading was developed and validated with wind tunnel data. The analytical model is described and results are given. Results are given for loading due to shocks and skin friction. The analysis included calculation of internal flow (porous media flow and channel flow) to obtain pressures and integration of the pressures to obtain forces and moments on an insulation tile. A heat transfer program was modified by using analogies between heat transfer and fluid flow so that it could be used for internal flow calculation. The type of insulation tile considered was undensified reusable surface insulation (RSI) without gap fillers, and the location studied was the lower surface of the orbiter. Force and moment results are reported for parameter variations on surface pressure distribution, gap sizes, insulation permeability, and tile thickness

Astrophysical limitations to the identification of dark matter: indirect neutrino signals vis-a-vis direct detection recoil rates

A convincing identification of dark matter (DM) particles can probably be achieved only through a combined analysis of different detections strategies, which provides an effective way of removing degeneracies in the parameter space of DM models. In practice, however, this program is made complicated by the fact that different strategies depend on different physical quantities, or on the same quantities but in a different way, making the treatment of systematic errors rather tricky. We discuss here the uncertainties on the recoil rate in direct detection experiments and on the muon rate induced by neutrinos from dark matter annihilations in the Sun, and we show that, contrarily to the local DM density or overall cross section scale, irreducible astrophysical uncertainties affect the two rates in a different fashion, therefore limiting our ability to reconstruct the parameters of the dark matter particle. By varying within their respective errors astrophysical parameters such as the escape velocity and the velocity dispersion of dark matter particles, we show that the uncertainty on the relative strength of the neutrino and direct-detection signal is as large as a factor of two for typical values of the parameters, but can be even larger in some circumstances.Comment: 12 pages, 3 figures. Improved presentation and Fig.3; clarifications, references and an appendix added; conclusions unchanged. Matches version published in PR