On some numerical difficulties in integrating the equations for one-dimensional nonequilibrium nozzle flow

Numerical difficulties in integrating equations for one dimensional nonequilibrium nozzle flow of ga

Application of pattern recognition techniques to the identification of aerospace acoustic sources

A pattern recognition system was developed that successfully recognizes simulated spectra of five different types of transportation noise sources. The system generates hyperplanes during a training stage to separate the classes and correctly classify unknown patterns in classification mode. A feature selector in the system reduces a large number of features to a smaller optimal set, maximizing performance and minimizing computation

Interaction of gases with lunar materials

The surface chemistry of Apollo 17 lunar fines samples 74220 (the orange soil) and 74241 (the gray control soil) has been studied by measuring the adsorption of nitrogen, argon, and oxygen (all at 77 K) and also water vapor (at 20 or 22 C). In agreement with results for samples from other missions, both samples had low initial specific surface areas, consisted of nonporous particles, and were attacked by water vapor at high relative pressure to give an increased specific surface area and create a pore system which gave rise to a capillary condensation hysteresis loop in the adsorption isotherms. In contrast to previous samples, both of the Apollo 17 soils were partially hydrophobic in their initial interaction with water vapor (both samples were completely hydrophilic after the reaction with water). The results are consistent with formation at high temperatures without subsequent exposure to significant amounts of water

Interaction of gases with lunar materials

Quantitative efforts to assess the surface properties of lunar fines, particularly water induced porosity are discussed. Data show that: (1) changes induced in lunar fines are not visible in high energy electron micrographs, (2) scanning micrographs show no change in particle size distribution as a result of reaction with water, (3) water induced changes are internal to the particles themselves, (4) normal laboratory atmosphere blocks alteration reaction with water, and (5) surface properties of mature lunar soils appear to be almost independent of chemical composition and mineralogy, but there are some variations in their reactivity toward water

World Trade Impacts of Foot and Mouth Disease in Taiwan

The recent ban on pork exports from Taiwan resulting from an outbreak of foot and mouth disease (FMD) in March 1997 will significantly alter future world trade patterns in pork. This study provides an in-depth analysis of the price and trade effects of this export ban. The analysis uses the Food and Agricultural Policy Research Institute (FAPRI) model of world agricultural production and trade to simulate the removal of Taiwan\u27s pork exports from world markets. The model enables examination of the interaction among pork, other meats, feed grains, and protein meal feeds

Brazil: The Future of Modern Agriculture?

In an attempt to understand better Brazil\u27s future role in agricultural markets, the authors of this report traveled to Brazil on a fact-finding mission in September 2003. The goal was to get a first-hand impression of Brazil\u27s agricultural sector and especially its future potential. In this report we provide a general description of crop and livestock production, government policies, public and private cooperation, and transportation and biotechnology issues. The most striking observations made during our time in Brazil was the universal sense of optimism expressed by producers, government officials, agronomists, and market analysts about the future growth of Brazilian agricultural production. Does that mean Brazil, as one person suggested, is the future of modern agriculture? Our answer to that question depends on one\u27s view of the future of global agriculture. Brazilian large-scale, commercially oriented, forward-looking operations are well suited to compete in commodity markets that are constantly driven to increase productivity and reduce costs. On the other hand, we observed factors within Brazil itself that have potential for creating tensions, which may ultimately force politicians to consider reforms that reduce production efficiency to achieve other social and environmental objectives

Impact of the Berlin Accord and European Enlargement on Dairy Markets, The

Using a world agricultural model, we analyze the impact on dairy markets of the Berlin Accord on the European Union (EU) Common Agricultural Policy (CAP) Reforms. We also investigate the consequences of enlargement of the EU to include the Czech Republic, Hungary and Poland for the same markets. We produce a market outlook up to 2010 for these two scenarios. The Berlin Accord induces lower EU milk and dairy prices. A change in relative prices between cheese and butter-skim milk powder (SMP) occurs after 2005 and induces an expansion of cheese production, consumption and exports at the expense of the butterï¾–SMP sector. Accession of the three central and eastern European countries (CEECs) leads to a permanent but moderate decrease in EU prices of milk and dairy products. For the three acceding CEECs, domestic prices increase dramatically. Their final consumption of milk decreases and dairy product consumption drops considerably. The derived demand of milk in dairy production increases, however, because of the higher prices for dairy products, benefiting dairy producers in these CEECs. Dairy exports of the three acceding countries to the EUï¾–15 increase by one to three orders of magnitude, despite building large inventories. The impact of accession on world markets is small.

Twist and writhe dynamics of stiff filaments

This letter considers the dynamics of a stiff filament, in particular the coupling of twist and bend via writhe. The time dependence of the writhe of a filament is $W_r^2\sim L t^{1/4}$ for a linear filament and $W_r^2\sim t^{1/2} / L$ for a curved filament. Simulations are used to study the relative importance of crankshaft motion and tube like motion in twist dynamics. Fuller's theorem, and its relation with the Berry phase, is reconsidered for open filamentsComment: 7 Pages with 2 figure

The power of heartbeats through the lens of ι Orionis

O star asteroseismology is a relatively new field which has not been able to gain significant traction due in large part to the lack of known pulsators in addition to the relatively sparse number of frequencies detected in those pulsators. This is likely due to a combination of factors, chief among them long frequencies, on the order of days, and weak amplitudes (≈ 1 mmag and below). Fortunately, through the discovery of the most massive heartbeat system ι Orionis and it's corresponding tidally induced oscillations with BRITE-Constellation there exists a new avenue with which to explore O star asteroseismology. In this paper we will give a prescription for using tidally induced oscillations to do asteroseismic analysis on O stars and present a list of candidate systems for this analysis within the BRITE sample