Numerical Computation of Satellite Orbits Using Lie Series. Comparison with Other Methods

Lie series for numerical computation of satellite orbit

Dynamic analysis of lunar gravity simulator

Dynamic analysis of lunar gravity simulato

Magnesium-air batteries

Magnesium-air batteries with anodic solutions having pH range of 6 to

Evaluating Drought Vulnerability of Small Community Surface Water Supply Systems in the Midwest

This report presents approaches and data availability for evaluating the drought vulnerability of small community water supply systems in the Midwest that obtain water from surface water bodies, such as rivers, streams, natural lakes, and man-made reservoirs. A description is provided of the various types of surface water sources from which 320 small community systems in the Midwest, each serving 10,000 or fewer people, obtain their water. The small community surface water system most commonly obtains its supply from one or two small impounding reservoirs. However, a substantial number of communities instead obtain their water from either direct river withdrawals or off-channel storage of water withdrawn from streams and rivers. Sixty of these 320 small community surface water systems were interviewed to gather information on the availability of data to determine the drought vulnerability of these systems. Although hydrologic and physical data exist for evaluating many of these systems, relatively few of the interviewed system managers could provide such pertinent information. A summary of selected hydrologic data is provided that can be used to determine the relative severity of major historical drought periods for various portions of the Midwest. Focus is given to historical droughts and available data for the southern portion of the Midwest where most surface water supply systems are located, comprising parts of Kansas, Missouri, Iowa, Illinois, Indiana, and Ohio. Geographic differences in drought severity are described, as is the influence of the physical characteristics of a water supply on the “critical” drought duration that a community must consider. Basic water budget analyses of water supplies and data needs are presented. Reservoir capacity measurements and estimates of inflow are the most critical data in reliable assessment of water supply adequacy. Depending on data availability, estimation of inflows may be straightforward to highly uncertain. For water supply systems that withdraw directly from a stream or river, the existence of long-term stream gage data on that river is particularly crucial to evaluate supply adequacy, and such data for larger streams and rivers are often available. With impounding reservoirs, which are typically located on smaller streams, data for that stream may often not exist; however, data from a “surrogate” gage that is considered to be hydrologically similar are often sufficient to estimate water supply yield. Systems that use off-channel reservoirs often withdraw water from smaller streams that do not have data for accurate depiction of their yield, and these systems also appear to be the most vulnerable to severe drought conditions. Case studies are presented to provide examples of yield calculations and innovative approaches that selected small communities have undertaken for addressing drought vulnerability. The role of demand management (drought response and water conservation) in evaluating drought vulnerability is also presented. If hydrologic data and basic physical data such as storage capacity are lacking, it may be difficult for either system managers or experienced professionals to estimate a community system’s yield and potential drought impacts, particularly for off-channel reservoir and low channel dam systems. However, managers should attempt to understand the type of drought period likely to test the adequacy of the available supply and can begin recording basic system observations, such as daily withdrawal records and reservoir drawdown, in a readily-accessible form that will be useful for future evaluations.published or submitted for publicationis peer reviewe

Design of minimax output feedback controller for system with parameter uncertainty

The problem of controlling a time-invariant system with parameter uncertainty is considered with incomplete state feedback. The controller is designed by minimaximizing a quadratic performance criterion and a sensitivity (or loss) criterion, involving the state of the system, the control, and the uncertainty vector. The resulting optimal controller is linear and optimal feedback gain matrix must satisfy a set of nonlinear algebraic equations. some algorithms for algebraic minimax problems are presented

CO observations of the expanding envelope of IRC plus 10216

High-sensitivity emission profiles were observed for the transition of C12O16 and C13O16 towards IRC + or - 10216. It appears that the spherically symmetric uniform mass-outflow model proposed by Morris is necessary to describe the line profiles. The outflow appears to be slightly accelerated, having a velocity of 15 km/sec at the edges of the CO cloud, compared with 12 km/sec for the more centrally confined molecules

Linear and nonlinear response of a rectangular plate subjected to lateral and inplane sonic boom disturbances

Transient response of rectangular window pane exposed to sonic boom disturbance using linear and nonlinear theorie

The Close Binary Fraction of Dwarf M Stars

We describe a search for close spectroscopic dwarf M star binaries using data from the Sloan Digital Sky Survey to address the question of the rate of occurrence of multiplicity in M dwarfs. We use a template-fitting technique to measure radial velocities from 145,888 individual spectra obtained for a magnitude-limited sample of 39,543 M dwarfs. Typically, the three or four spectra observed for each star are separated in time by less than four hours, but for ~17% of the stars, the individual observations span more than two days. In these cases we are sensitive to large-amplitude radial velocity variations on timescales comparable to the separation between the observations. We use a control sample of objects having observations taken within a four-hour period to make an empirical estimate of the underlying radial velocity error distribution and simulate our detection efficiency for a wide range of binary star systems. We find the frequency of binaries among the dwarf M stars with a < 0.4 AU to be 3%-4%. Comparison with other samples of binary stars demonstrates that the close binary fraction, like the total binary fraction, is an increasing function of primary mass

Active clearance control system for a turbomachine

An axial compressor is provided with a cooling air manifold surrounding a portion of the shroud, and means for bleeding air from the compressor to the manifold for selectively flowing it in a modulating manner axially along the outer side of the stator/shroud to cool and shrink it during steady state operating conditions so as to obtain minimum shroud/rotor clearance conditions. Provision is also made to selectively divert the flow of cooling air from the manifold during transient periods of operation so as to alter the thermal growth or shrink rate of the stator/shroud and result in adequate clearance with the compressor rotor

You\u27re the Top: Illustrated Sheet Music of American Popular Songs from World War I to the 1940s

Guide to an exhibition held by Watkinson Library, 2006