A High Current Proton Linac with 352 MHz SC Cavities

A proposal for a 10-120 mA proton linac employing superconducting beta-graded, CERN type, four cell cavities at 352 MHz is presented. The high energy part (100 MeV-1 GeV) of the machine is split in three beta-graded sections, and transverse focusing is provided via a periodic doublet array. All the parameters, like power in the couplers and accelerating fields in the cavities, are within the state of the art, achieved in operating machines. A first stage of operation at 30 mA beam current is proposed, while the upgrade of the machine to 120 mA operation can be obtained increasing the number of klystrons and couplers per cavity. The additional coupler ports, up to four, will be integrated in the cavity design. Preliminary calculations indicate that beam transport is feasible, given the wide aperture of the 352 MHz structures. A capital cost of less than 100 M$at 10 mA, reaching up to 280 M$ for the 120 mA extension, has been estimated for the superconducting high energy section (100 MeV-1 GeV). The high efficiency of the proposed machine, reaching 50% at 15 mA, makes it a good candidate for proposed nuclear waste incineration facilities and Energy Amplifier studies.Comment: 9 Pages, 4 figures, LaTeX2e, html version found from http://hptesla.mi.infn.it/~pierini/publication_list.html . To Appear in the Proceedings of the 1996 LINAC Conference, Geneve, August 26-30 199

Using deuterated H3+ and other molecular species to understand the formation of stars and planets

The H3+ ion plays a key role in the chemistry of dense interstellar gas clouds where stars and planets are forming. The low temperatures and high extinctions of such clouds make direct observations of H3+ impossible, but lead to large abundances of H2D+ and D2H+ which are very useful probes of the early stages of star and planet formation. Maps of H2D+ and D2H+ pure rotational line emission toward star-forming regions show that the strong deuteration of H3+ is the result of near-complete molecular depletion of CNO-bearing molecules onto grain surfaces, which quickly disappears as cores warm up after stars have formed. In the warmer parts of interstellar gas clouds, H3+ transfers its proton to other neutrals such as CO and N2, leading to a rich ionic chemistry. The abundances of such species are useful tracers of physical conditions such as the radiation field and the electron fraction. Recent observations of HF line emission toward the Orion Bar imply a high electron fraction, and we suggest that observations of OH+ and H2O+ emission may be used to probe the electron density in the nuclei of external galaxies.Comment: Proceedings of the H3+ centennial symposium, to be published in RSPTA (editor: T. Oka

Universal Local symmetries and non-superposition in classical mechanics

In the Hilbert space formulation of classical mechanics (CM), pioneered by Koopman and von Neumann (KvN), there are potentially more observables that in the standard approach to CM. In this paper we show that actually many of those extra observables are not invariant under a set of universal local symmetries which appear once the KvN is extended to include the evolution of differential forms. Because of their non-invariance, those extra observables have to be removed. This removal makes the superposition of states in KvN, and as a consequence also in CM, impossible

Chemistry and kinematics of the pre-stellar core L1544: Constraints from H2D+

This paper explores the sensitivity of line profiles of H2D+, HCO+ and N2H+, observed towards the center of L1544, to various kinematic and chemical parameters. The total width of the H2D+ line can be matched by a static model and by models invoking ambipolar diffusion and gravitational collapse. The derived turbulent line width is b=0.15 km/s for the static case and <~ 0.05 km/s for the collapse case. However, line profiles of HC18O+ and N2H+ rule out the static solution. The double-peaked H2D+ line shape requires either infall speeds in the center that are much higher than predicted by ambipolar diffusion models, or a shell-type distribution of H2D+, as is the case for HCO+ and N2H+. At an offset of ~20 arcsec from the dust peak, the H2D+ abundance drops by a factor of ~5.Comment: four pages, two colour figures; to appear in The Dense Interstellar Medium in Galaxies, proceedings of the fourth Cologne-Bonn-Zermatt Symposium, Sept 22-26, 200

Change of Soil pH over Time as Affected by Lime Sources and Application Rates

Agricultural limestone is commonly used in Iowa to maintain optimum soil pH for crops. However, there is insufficient information concerning the reaction time of lime sources in the soil and short-term effects on crop yield for different sources and application rates. This information is needed to improve soil pH management and lime recommendations. The objective of this study was to study the soil pH and crop response to the application of pure calcium carbonate (CaCO3), and calcitic or dolomitic limestone in a typical acid soil of northeast Iowa

Soil pH Change over Time as Affected by the Limestone Sources and Application Rate

Limestone is commonly used in Iowa to maintain optimum soil pH for crop production. There is insufficient information, however, concerning the reaction time in the soil and short-term effects on crop yield for different sources and application rates. This information is needed to improve soil pH management and lime recommendations. The objective of this study was to study the soil pH and crop response to the application of pure calcium carbonate (CaCO3), and calcitic or dolomitic limestone in a typical acid soil of central Iowa

Soil pH Change as Affected by the Lime Source and Application Rates

Agricultural limestone is commonly used in Iowa to maintain optimum soil pH for crops. There is insufficient information, however, concerning the reaction time of lime sources in the soil and short-term effects on crop yield for different sources and application rates. This information is needed to improve soil pH management and lime recommendations. The objective of this study was to study the soil pH and crop response to the application of pure calcium carbonate (CaCO3), and calcitic or dolomitic limestones in a typical acidic soil of southwest Iowa

Soil pH Change over Time as Affected by Sources and Application Rates of Liming Materials

Agricultural limestone is commonly applied to maintain optimum soil pH for crops. There is insufficient information, however, about short-term effects of different lime sources and application rates on soil pH changes over time and crop yield. This information is needed to improve soil pH and lime management. The objective of this experiment was to study the soil pH and crop yield response to application of pure calcium carbonate, calcitic limestone, and dolomitic limestone

Host Galaxies of low z Radio-loud Quasars: A search of HST archives

We searched the HST archives for unpublished WFPC2 images of low redshift (z<0.5) radio loud quasars (RLQ). This led to the identification of 11 objects. We present here the results of the analysis of these images from which we derive the properties of their host galaxies. All objects are clearly resolved and their surrounding nebulosity is consistent with an elliptical galaxy model. These new data, together with previous published HST observations, form a sample of 34 sources which significantly expands all previous studies of low redshift RLQ based on HST data. For this full sample we derive the average absolute magnitude of the host galaxies =-24.01+/-0.48, and the effective radius =10.5+/-3.7kpc. No significant correlation is found between the nucleus and the host galaxy luminosity. Using the relationship between black hole mass (M_BH) and bulge luminosity we investigate the relation between M_BH and total radio power for RLQ and compare with other classes of radio sources. The overall distribution of AGN in the plane M_BH-P(radio) exhibits a trend for increasing M_BH with increasing P(radio) but with a substantial spread. RLQ occupy the region of most powerful sources and most massive BH. The quasars appear to emit over a wide range of power with respect to their Eddington luminosity as deduced by the estimated M_BH.Comment: 23 pages, 8 figures, ApJ in pres