Design and development criteria for metal bellows

Experimental research describes fluid flow and the fluid-elastic mechanism causing bellows flow excitation, and aids in design of conventional bellows liner which suppresses flow-induced vibrations. Analytical models facilitate prediction of flow excitation occurrence and estimation of severity of bellows vibrations

State-Dependent Stock Market Reactions to Monetary Policy

This paper presents a test of the response of stock prices to Federal Reserve policy shocks using a Markov-switching framework. The framework endogenously identifies two distinct regimes. The first is a state where the S&P 500 index exhibits a significantly negative response to unexpected changes in the target federal funds rate in the thirty-minute window bracketing FOMC announcements, a result consistent with previous work. However, the model identifies a second regime from September 1998 to September 2002, in which the response of stock prices to policy shocks is insignificant and over ten times more volatile relative to the other regime.�

Facilities for meteorological research at NASA Goddard/Wallops Flight Facility

The technical characteristics of the Atmospheric Sciences Research Facility, the improvements being made to the instrumentation there which will enhance its usefulness in atmospheric research, and several of the on-going research programs are described. Among the area of atmospheric research discussed are clouds and precipitation, lightning, ozone, wind, and storms. Meteorological instruments including Doppler radar, spectrophotometers, and ozone sensors are mentioned. Atmospheric research relevant to aircraft design and COMSTAR communication satellites is briefly discussed

Study of fluid transients in closed conduits progress report no. 64-5, 1-30 nov. 1964

Fluid transients in closed conduit

Design of fluid-duct bends with low pressure loss

Duct bends are designed in which pressure losses and velocity profile distortions due to centrifugal force gradients are significantly reduced. The correction is achieved by properly changing the cross sectional area through the bend without affecting the shape of the duct at the upstream and downstream sides

Coulomb field of an accelerated charge: physical and mathematical aspects

The Maxwell field equations relative to a uniformly accelerated frame, and the variational principle from which they are obtained, are formulated in terms of the technique of geometrical gauge invariant potentials. They refer to the transverse magnetic (TM) and the transeverse electric (TE) modes. This gauge invariant "2+2" decomposition is used to see how the Coulomb field of a charge, static in an accelerated frame, has properties that suggest features of electromagnetism which are different from those in an inertial frame. In particular, (1) an illustrative calculation shows that the Larmor radiation reaction equals the electrostatic attraction between the accelerated charge and the charge induced on the surface whose history is the event horizon, and (2) a spectral decomposition of the Coulomb potential in the accelerated frame suggests the possibility that the distortive effects of this charge on the Rindler vacuum are akin to those of a charge on a crystal lattice.Comment: 27 pages, PlainTex. Related papers available at http://www.math.ohio-state.edu/~gerlac

Ion-tracer anemometer

Gas velocity measuring instrument measures transport time of ion-trace traveling fixed distance between ionization probe and detector probe. Electric field superimposes drift velocity onto flow velocity so travel times can be reduced to minimize ion diffusion effects

Forecasting Value-at-Risk Using Nonlinear Regression Quantiles and the Intraday Range

Value-at-Risk (VaR) is commonly used for financial risk measurement. It has recently become even more important, especially during the 2008-09 global financial crisis. We propose some novel nonlinear threshold conditional autoregressive VaR (CAViar) models that incorporate intra-day price ranges. Model estimation and inference are performed using the Bayesian approach via the link with the Skewed-Laplace distribution. We examine how a range of risk models perform during the 2008-09 financial crisis, and evaluate how the crisis affects the performance of risk models via forecasting VaR. Empirical analysis is conducted on five Asia-Pacific Economic Cooperation stock market indices and two exchange rates????. We examine violation rates, back-testing criteria, market risk charges and quantile loss function to measure the forecasting performance of a variety of risk models. The proposed threshold CAViaR model, incorporating range information, is shown to forecast VaR more efficiently than other models, which should be useful for financial practitioners.Markov chain Monte Carlo;backtesting;Value-at-Risk;CAViaR model;Skewed-Laplace distribution;intra-day range

Evaluation of a possible subsurface impact crater: the Newporte structure, northwestern Renville County, North Dakota

The purpose of this study was to determine if enough evidence exists to support an impact origin hypothesis the Newporte structure. Newporte, a petroliferous, subsurface, crater-shaped feature is located one mile south of the North Dakota - Saskatchewan border in Renville County. It is evident in Precambrian through Ordovician strata at depths of 9100 to 9600 ft (2774 to 2926 m) structure is approximately 2.0 miles (J.2 km) in diameter. Shell Oil company discovered Newporte field when testing this seismically-defined structure in 1977. Seismic reflection profiling data and synthetic seismograms were used to generate maps that confirmed the circularity of the structure. Because no wells have been drilled in the central region of the structure, the seismic data were necessary for mapping and interpreting the morphology of the feature. Wireline logs of the seven wells, all located on the remaining rim, were used to identify lithologic units, verify the seismic data, and they were used in an attempt to interpret the age of the Newporte structure. All available well cores were described (Appendix B), and nearly 140 thin sections were evaluated microscopic evidence of shock metamorphism. Interpretation of seismic data reveals a crater with a distinctive raised rim, and what may be vestiges of a central uplift. Intriguing breccias, resembling impact breccia, have been described from three well cores. Several examples of unusual microscopic features, perhaps indicative of low shock pressures, were discovered in quartz from sandstone and brecciated crystalline rock from the Mott 14 34 well. It has been concluded in this study, based on geophysical data, well core samples, and a thorough microscopic evaluation that there is much evidence to support an impact origin for the Newporte structure. The presence of a Deadwood breccia interval suggests the impact event may have occurred during or after Deadwood deposition, prior to deposition of the Winnipeg Group (Late Cambrian to Early Ordovician, or prior to Late Ordovician