LOX manifold tee analysis

A 4000 Hz vibration phenomena was observed during the test firings of several space shuttle main engines (SSME). Experimental studies of this phenomena suggest that the problem might be associated with vortex shedding from the vanes within the LOX tee manifold. The objective of this study was to determine the unsteady, 3-D flow associated with these vanes by computational methods to identify and better understand the 4000 Hz vibration phenomena. A flow solver, FDNS, for the turbulent conservation equations was validated for predicting high frequency vortex dynamics and used to predict 2-D and 3-D flows within the LOX tee. 4000 Hz excitation oscillations were predicted for some flows and the entire 3-D flow structure was predicted for LOX tee flow. The complexity of the flow was revealed by this analysis, and computational methods for predicting these high frequency oscillations in future engine systems were established

'If I cannot access services then there is no reason for me to test': the impact of health service charges on HIV testing and treatment amongst migrants in England

Policy governing entitlement to access government health care for foreign nationals in England is a subject of debate, controversy and confusion. Of particular concern to health providers has been the impact of National Health Service charges on delaying HIV testing and anti-retroviral treatment uptake and adherence amongst certain migrant groups. Data obtained through focus groups with 70 migrants from southern Africa, suggest that confusion over health care entitlements exists amongst those seeking health care and is reported amongst health service providers. This confusion, as well as financial difficulties and fears over deportation facing some migrants, can in turn be a factor influencing their decisions to avoid formal health services, resort to alternative and often ineffective or potentially adverse forms of therapy, and delay HIV testing and treatment uptake

Distortions to Agricultural Incentives in Australia and New Zealand

In 1990, Australia and New Zealand were ranked around 25th and 35th in terms of GNP per capita, having been the highest-income countries in the world one hundred years earlier. The poor performance over that long period contrasts markedly with that of the past 15 years, when these two economies out-performed most other high-income countries. This difference in growth performance is due to major economic policy reforms during the past two to three decades. We provide new evidence on the extent of governmental distortions to agricultural incentives in particular in the two economies since the late 1940s, both directly and indirectly (and negatively) via manufacturing protection.Distorted incentives, agricultural and trade policy reform, Agricultural and Food Policy, F13, F14, Q17, Q18,

The Polynomial Method Augmented by Supervised Training for Hand-Printed Character Recognition

We present a pattern recognition algorithm for hand-printed characters, based on a combination of the classical least squares method and a neural-network-type supervised training algorithm. Characters are mapped, nonlinearly, to feature vectors using selected quadratic polynomilas of the given pixels. We use a method for extracting an equidistributed subsample of all possible quadratic features. This method creates pattern classifiers with accuracy competitive to feed-forward systems trained using back propagation; however back propagation training takes longer by a factor of ten to fifty. (This makes our system particularly attractive for experimentation with other forms of feature representation, other character sets, etc.) The resulting classifier runs much faster in use than the back propagation trained systems, because all arithmetic is done using bit and integer operations

Typewriter Keyboards via Simulated Annealing

We apply the simulated annealing algorithm to the combinatorial optimization problem of typewriter keyboard design, yielding nearly optimal key-placements using a figure of merit based on English letter pair frequencies and finger travel-times. Our keyboards are demonstrably superior to both the ubiquitous QWERTY keyboard and the less common Dvorak keyboard. The paper is constructed as follows: first we discuss the historical background of keyboard design; this includes August Dvorak\u27s work, and a figure-of-merit (scalar) metric for keyboards. We discuss a theory of keyboard designs: why keyboard design is a combinatorial problem, how combinatorial problems are typically solved, what is simulated annealing, and why it is especially suitable for the problem at hand. Next we discussed the results, and compare the keyboards produced by simulated annealing to QWERTY and Dvorak\u27s keyboard. Finally, we suggest some future lines of inquiry

Does money matter in inflation forecasting?

This paper provides the most fully comprehensive evidence to date on whether or not monetary aggregates are valuable for forecasting US inflation in the early to mid 2000s. We explore a wide range of different definitions of money, including different methods of aggregation and different collections of included monetary assets. In our forecasting experiment we use two non-linear techniques, namely, recurrent neural networks and kernel recursive least squares regression - techniques that are new to macroeconomics. Recurrent neural networks operate with potentially unbounded input memory, while the kernel regression technique is a finite memory predictor. The two methodologies compete to find the best fitting US inflation forecasting models and are then compared to forecasts from a naive random walk model. The best models were non-linear autoregressive models based on kernel methods. Our findings do not provide much support for the usefulness of monetary aggregates in forecasting inflation.Forecasting ; Inflation (Finance) ; Monetary theory

Theory of Structural Glasses and Supercooled Liquids

We review the Random First Order Transition Theory of the glass transition, emphasizing the experimental tests of the theory. Many distinct phenomena are quantitatively predicted or explained by the theory, both above and below the glass transition temperature $T_g$. These include: the viscosity catastrophe and heat capacity jump at $T_g$, and their connection; the non-exponentiality of relaxations and their correlation with the fragility; dynamic heterogeneity in supercooled liquids owing to the mosaic structure; deviations from the Vogel-Fulcher law, connected with strings or fractral cooperative rearrangements; deviations from the Stokes-Einstein relation close to $T_g$; aging, and its correlation with fragility; the excess density of states at cryogenic temperatures due to two level tunneling systems and the Boson Peak.Comment: submitted to Ann. Rev. Phys. Che

Ground failure along the New River caused by the October 1979 Imperial Valley earthquake sequence

We recognized a number of ground failures along the south bank of the New River north of Brawley, California, following the 15 October 1979 Imperial Valley, California, earthquake sequence. The zone includes a large pond and numerous sand boils, apparently caused by liquefaction, near the Del Rio Country Club. These ground failures, together with failures at the New River bridge west of Brawley and at Wiest Lake, form a discontinuous zone 10 km long. While this zone appears to coincide with the aftershocks following the 16 October 1979, M_L 5.8, Brawley earthquake (the largest aftershock of the Imperial Valley earthquake), a cause and effect relationship cannot be demonstrated. No evidence of tectonic surface faulting could be found

Reviews

Reviews of Trade Unionism Under Collective Bargaining: A Theory Based on Comparisons of Six Countries, Union Growth and the Business Cycle, Industrial Relations: A Textboo

Spin-Orbital Entanglement and Violation of the Goodenough-Kanamori Rules

We point out that large composite spin-orbital fluctuations in Mott insulators with $t_{2g}$ orbital degeneracy are a manifestation of quantum entanglement of spin and orbital variables. This results in a dynamical nature of the spin superexchange interactions, which fluctuate over positive and negative values, and leads to an apparent violation of the Goodenough-Kanamori rules. [{\it Published in Phys. Rev. Lett. {\bf 96}, 147205 (2006).}]Comment: 4 pages, 2 figure