High level of 3^3He polarization of 81\% Maintained in an on-beam 3^3He spin filter using SEOP

Maintaining high levels of 3He polarization over long periods of time is important to many areas of fundamental and particle beam physics. Long measurement times are often required in such experiments and the data quality is a function of the 3He polarization. This is the case for neutron scattering where the 3He can be used to analyze the spin of a scattered neutron beam and relatively small fluxes of polarized neutrons leads to experiment times longer than several days. Consequently the J\"ulich Centre for Neutron Science (JCNS) is developing spin-exchange optical pumping (SEOP) systems capable of polarizing the 3He gas in place on a typical neutron instrument. Using a polarizer device we constructed a high level of 3He polarization of 81 % \pm2% was maintained with good time stability. Such levels of polarization maintained over time will be able to reduce the measurement times for such experiments and eliminate time dependent data corrections.Comment: 4 pages 2 figure

The effect of end slope on the buckling stress of cylindrical shells

End slope effect on buckling stress of seamless cylindrical shell

Heat and Moisture Conduction in Unsaturated Soils

Mathematical models are developed for the prediction of heat transfer from hot water pipes buried in the soil. Heat transfer in the absence of moisture transfer is described as a function of the difference between the temperature of the pipe and the temperature of the soil surface. The energy balance is used to determine the longitudinal temperature distribution of the water. The method is extended to describe a system of equally spaced, parallel buried pipes. Soil temperature profiles around the pipes are presented. The model is used to calculate the land area that can be heated by an underground piping system carrying cooling water from the condensers of a 1000 MW nuclear-electric plant. A new development of the phenomenological equations for coupled heat and moisture flow, based on the theory of Irreversible Thermodynamics, is presented. Solutions of the equations for boundary conditions representative of buried piping systems designed for simultaneous soil heating and irrigation are presented

U.S. Farm Policy and the WTO: How Do They Match Up?

The debate over a new farm bill has focused on how to spend an additional $73.5 billion in funding for the agricultural budget over ten years. The House of Representatives, the Senate Agriculture Committee, and Senators Cochran and Roberts (supported by the Bush Administration) have each proposed a structure for the next farm bill. A critical question becomes whether these proposals conflict with U.S. commitments to limit subsidies under the World Trade Organization (WTO) agreement. This paper explores this issue and concludes with a discussion of the future direction of U.S. farm subsidies and new WTO agreements.agricultural policy, domestic support, trade commitments, WTO, Agricultural and Food Policy, International Relations/Trade,

COMMODITY POLICY, PRICE INCENTIVES, AND THE GROWTH IN PER-ACRE YIELDS

We estimate the influence of policy-induced price changes and of technology supply on North Carolina flue-cured tobacco yields. The decline in land rent and effective output price that accompanied a 1965 policy change from acreage allotments to poundage quotas caused a 12 percent decrease in yields. Farmer yields were more responsive to yield-increasing technologies under acreage allotments than under poundage quotas. Annual yield growth was 0.5 percent under poundage quotas and 4.32 percent under acreage allotments. The growth rate decline is attributable to changes in relative prices and to a slowdown in the supply of available technologies.Commodity policy, Endogenous yield growth, Flue-cured tobacco, Technical change, Agricultural and Food Policy, Demand and Price Analysis, Research and Development/Tech Change/Emerging Technologies,

U.S. Farm Policy and the World Trade Organization: How Do They Match Up?

The debate over a new farm bill has focused on how to spend an additional $73.5 billion in funding for the agricultural budget over 10 years. The House of Representatives, the Senate agriculture committee, and Senators Cochran and Roberts (supported by the Bush administration) have each proposed a structure for the next farm bill. A critical question becomes whether these proposals conflict with U.S. commitments to limit subsidies under the World Trade Organization (WTO) agreement. This paper explores this issue and concludes with a discussion of the future direction of U.S. farm subsidies and new WTO agreements.

Welding monitoring system

This invention relates to systems for remotely monitoring automatic welding operations, and more particularly to a system wherein the welder is readily positionable, while components of the optical system remain fixed. A welder having an electrode is mounted in an enclosure containing a pair of mirrors. The electrode passes through an opening in the first mirror and a gas cup. The mirror reflects an image of a welding operation taken through the opening of the gas cup to the second mirror. The second mirror then reflects the image through a rotary coupling to a third mirror which, in turn, reflects the image to a receiving lense mounted to a second rotatable coupling. The image is then projected via a fiber optic bundle to a filter unit where selected wavelengths of light are filtered from the welding image. The filter unit is coupled to an enlarger which enlarges the image and passes it to a camera. The camera is connected to an electronic eclipser which selectively darkens the brightest portions of the image. Finally, the image is recorded by a video tape recorder and displayed by a monitor

Circular Dichroism of RbHe and RbN2_2 Molecules

We present measurements of the circular dichroism of optically pumped Rb vapor near the D1 resonance line. Collisions with the buffer gases $^3$He and N$_2$ reduce the transparency of the vapor, even when fully polarized. We use two methods to measure this effect, show that the He results can be understood from RbHe potential curves, and show how this effect conspires with the spectral profile of the optical pumping light to increase the laser power demands for optical pumping of very optically thick samples

Theoretical isochrones for the Delta a photometric system

We have calculated theoretical isochrones for the photometric Delta a system to derive astrophysical parameters such as the age, reddening and distance modulus for open clusters. The Delta a system samples the flux depression at 520 nm which is highly efficient to detect chemically peculiar (CP) objects of the upper main sequence. The evolutionary status of CP stars is still a matter of debate and very important to test, for example, the dynamo and diffusion theories. In fact, the dynamo or fossil origin of the magnetic fields present in this kind of stars it still not clear. Using the stellar evolutionary models by Claret (1995), a grid of isochrones with different initial chemical compositions for the Delta a system was generated. The published data of 23 open clusters were used to fit these isochrones with astrophysical parameters (age, reddening and distance modulus) from the literature. As an additional test, isochrones with the same parameters for Johnson UBV data of these open clusters were also considered. The fits show a good agreement between the observations and the theoretical grid. We find that the accuracy of fitting isochrones to Delta a data without the knowledge of the cluster parameters is between 5 and 15%.Comment: 5 pages, 4 figures, accepted by A&