Detection and clearing of trapped ions in the high current Cornell photoinjector

We have recently performed experiments to test the effectiveness of three ion-clearing strategies in the Cornell high intensity photoinjector: DC clearing electrodes, bunch gaps, and beam shaking. The photoinjector reaches a new regime of linac beam parameters where high CW beam currents lead to ion trapping. Therefore ion mitigation strategies must be evaluated for this machine and other similar future high current linacs. We have developed several techniques to directly measure the residual trapped ions. Our two primary indicators of successful clearing are the amount of ion current removed by a DC clearing electrode, and the absence of bremsstrahlung radiation generated by beam-ion interactions. Measurements were taken for an electron beam with an energy of 5 MeV and CW beam currents in the range of 1-20 mA. Several theoretical models have been developed to explain our data. Using them, we are able to estimate the clearing electrode voltage required for maximum ion clearing, the creation and clearing rates of the ions while employing bunch gaps, and the sinusoidal shaking frequency necessary for clearing via beam shaking. In all cases, we achieve a maximum ion clearing of at least 70 percent or higher, and in some cases our data is consistent with full ion clearing

Some Observations of the Boiling Point of Ternary Liquid Mixtures

An exposition of an apparatus for the determination of the boiling points of liquid mixtures under constant pressure, and the results of preliminary investigations upon ternary mixtures of some common organic liquids

Smoking Laws and Their Differential Effects on Restaurants, Bars, and Taverns

This article examines the effect of restrictive smoking laws on restaurants, bars, and taverns. Supporters of these laws often argue that they do not harm firms and may even raise profits. Opponents argue that owners cater to customer smoking preferences, and laws mandating specific policies will negatively impact profits. This article provides a framework for examining the distribution of effects that smoking laws exert on businesses, and demonstrates that changes in total sales or tax revenues do not provide a meaningful understanding of the economic implications because smoking laws exert different effects on different firms. The distribution of these effects is examined using data from a nationwide survey of 1,300 restaurant, bar, and tavern owners. While some subsets of firms are predicted to suffer revenue declines, bars are predicted to be more than twice as likely to experience losses as restaurants. An important implication is that the increasing level of governmental restrictions on smoking in the hospitality sector could gradually impact the types of service available to the public

Combining asteroid models derived by lightcurve inversion with asteroidal occultation silhouettes

Asteroid sizes can be directly measured by observing occultations of stars by asteroids. When there are enough observations across the path of the shadow, the asteroid's projected silhouette can be reconstructed. Asteroid shape models derived from photometry by the lightcurve inversion method enable us to predict the orientation of an asteroid for the time of occultation. By scaling the shape model to fit the occultation chords, we can determine the asteroid size with a relative accuracy of typically ~ 10%. We combine shape and spin state models of 44 asteroids (14 of them are new or updated models) with the available occultation data to derive asteroid effective diameters. In many cases, occultations allow us to reject one of two possible pole solutions that were derived from photometry. We show that by combining results obtained from lightcurve inversion with occultation timings, we can obtain unique physical models of asteroids.Comment: 33 pages, 45 figures, 4 tables, accepted for publication in Icaru

The Private Market for Accommodation: Determinants of Smoking Policies in Restaurants and Bars

This study finds an active private market in accommodation of smokers and nonsmokers in Wisconsin restaurants. Empirical analysis indicates that a large number of factors underlie owner decisions regarding how to allocate seating to non-smoking use. Owners not only base their decision on the number of smokers in their community, but also consider customer occupations, presence of children, and whether businesses are located in college towns, as well as type of restaurant and whether the establishment has a general liquor license. Business age, numbers of seats, and membership in a corporate chain also underlie decisions made in the private market for accommodation. Government smoking restrictions that are less than bans overturn all of the factors that owners previously found critical to their choices of accommodation policies, except for the number of smokers in their client base. These findings indicate that an active private market in accommodation is consistent with diversity of smoking policies.Smoking

MF789REVISED

James R. Dunham & John F. Smith, Characteristics of Low Somatic Cell Count (SCC) Herds, October 1985

96-GT-62 COMPRESSOR OFF-DESIGN PERFORMANCE PREDICTION USING AN ENDWALL MODEL

ABSTRACT A throughflow method for designing and analysing compressors has to be supplied with loss, deviation, and blockage estimates for every blade row. The earliest methods used empirical correlations for profile loss and deviation, together with an empirical blockage or "work done" factor, and empirical estimates of additional losses near the endwalls. Previous papers by the author have described how to replace the empirical blockage factor and endwall corrections by explicit calculations using a new mathematical model of the endwall phenomena. Those papers illustrated the application of the method near design conditions, using either design profile loss and deviation figures or computations by a viscous-inviscid interaction blade-to-blade method. In order to estimate off-design performance rapidly over the whole operating range, some way of estimating off-design profile loss encl.deviation must be chosen. In this paper, the previously-derived design point loss and deviation figures are retained, and an empirical correlation due to Miller, Wasdell, and Wright is Used to predict the changes in loss and deviation off-design. It is shown by means of sample threedimensional Nat-Stokes computations that the endwall model remains applicable off-design. The method has been tested against two low speed and two high speed compressors, one of each example having controlled-diffusion blading. The low speed compressor characteristic maps are predicted only approximately, but the predicted high speed compressor maps are good. It is widely believed that endwall flow separation can initiate stall or surge. As stall or surge was approached the shape factor of the annulus wall boundary layer at one location rose sharply, but no single stall-predicting value could be found