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

PRICE DISCOVERY ISSUES AND TRENDS IN CATTLE AND HOG MARKETS

Livestock Production/Industries, Marketing,

Price Discovery and Captive Supply Implications for the Canadian Beef Industry

As cattle markets have transitioned from predominantly cash market sealed-bid or negotiated price discovery to more formula pricing, marketing agreements, forward contracts, and packer-owned cattle feeding, concerns about methods of price discovery for fed cattle have escalated. High levels of concentration in beef packing in Canada were exacerbated by cattle trade restrictions with the United States that limited market access and thus caused further unease with the price discovery process for fed cattle in Canada.Marketing,

A gas flow indicator for portable life support systems

A three-part program was conducted to develop a gas flow indicator (GFI) to monitor ventilation flow in a portable life support system. The first program phase identified concepts which could potentially meet the GFI requirements. In the second phase, a working breadboard GFI, based on the concept of a pressure sensing diaphragm-aneroid assembly connected to a venturi, was constructed and tested. Extensive testing of the breadboard GFI indicated that the design would meet all NASA requirements including eliminating problems experienced with the ventilation flow sensor used in the Apollo program. In the third program phase, an optimized GFI was designed by utilizing test data obtained on the breadboard unit. A prototype unit was constructed using prototype materials and fabrication techniques, and performance tests indicated that the prototype GFI met or exceeded all requirements

The dynamic analysis of submerged structures

Methods are described by which the dynamic interaction of structures with surrounding fluids can be computed by using finite element techniques. In all cases, the fluid is assumed to behave as an acoustic medium and is initially stationary. Such problems are solved either by explicitly modeling the fluid (using pressure or displacement as the basic fluid unknown) or by using decoupling approximations which take account of the fluid effects without actually modeling the fluid

CATTLE FEEDER PERCEPTIONS OF LIVESTOCK MANDATORY PRICE REPORTING

Because of the significant investment in the mandatory price reporting program (MPR) by the USDA and by packers, it is important to understand what producers believe about its effectiveness. This study reports results from a survey of feedyards located primarily in Kansas, Nebraska, Texas, and Iowa. Results indicate a diversity of opinion regarding MPR effectiveness. On average producers are neutral to negative regarding the value of MPR to them. Interestingly, feedlot characteristics appear to have little systematic relationship to the manager's perceptions regarding the usefulness of MPR.Livestock Production/Industries,

Electromagnetic cascade in high energy electron, positron, and photon interactions with intense laser pulses

The interaction of high energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution, which suppresses the emission of high energy photons, thus reducing the number of electron-positron pairs being generated. Therefore, this type of interaction suppresses the development of the electromagnetic avalanche-type discharge, i.e., the exponential growth of the number of electrons, positrons, and photons does not occur in the course of interaction. The suppression will occur when 3D effects can be neglected in the transverse particle orbits, i.e., for sufficiently broad laser pulses with intensities that are not too extreme. The final distributions of electrons, positrons, and photons are calculated for the case of a high energy e-beam interacting with a counter-streaming, short intense laser pulse. The energy loss of the e-beam, which requires a self-consistent quantum description, plays an important role in this process, as well as provides a clear experimental observable for the transition from the classical to quantum regime of interaction.Comment: 13 pages, 7 figure

Impacts from Government Regulations on the Canadian-U.S. Basis for Fed Cattle

Replaced with revised version of paper 09/01/09.Canada, Fed Cattle, Government Policy, International Trade, Prices, U.S., Livestock Production/Industries, Marketing, Q13, Q17, Q18,

Trade-Related Policy and Canadian-U.S. Fed Cattle Transactions Basis

Price differences among fed cattle prices in Canada and the United States (referred to here as fed cattle basis) are important for Canadian cattle feeders, but changing government regulations in Canada and the United States have made basis more variable. This article uses transaction data from Canadian feedlots to quantify fed cattle price differentials in light of new policy initiatives. Using transaction prices, we find that differing slaughter regulations, labeling laws, and policies affecting access to U.S. markets for Canadian cattle affect fed cattle basis.basis, Canada, cattle prices, government policy, international trade, market access, transaction prices, International Relations/Trade, Livestock Production/Industries,