Construction of a Laboratory to Measure Livestock Emissions

A facility at Iowa State University was constructed to evaluate the impact diet modification has on air emissions. The facility was designed and constructed to have the unique ability to investigate emissions from cattle, poultry and swine by incorporating interchangeable penning and watering systems. Excreta and manure volumes can be measured for group-housed animals. Gas emissions are determined by measuring airflow rates through each of the eight animal chambers and multiplying airflow by the change in contaminate concentration between the effluent and influent ventilation air for each chamber. Chambers are monitored sequentially, for 15 min each, with incoming air gas concentrations subtracted from chamber gas concentrations, providing 10-11 observations per chamber each day. Each chamber is independently heated or air conditioned based on a temperature setpoint, with air delivered from a central plenum into chamber-specific variable air volume boxes. Data acquisition is coordinated through software control, including an emergency alarm system should ventilation problems arise. Findings from the first swine study conducted in the facility indicate that this facility can discriminate between emissions from animals fed diets that are modified to reduce nutrient excretions while maintaining animal performance. A brief laying hen study followed to challenge the sensitivity of the system to small dietary changes

“Exploring the Basement of Social Justice Issues”: A Graduate Upon Graduation

Photograph of rides building up, taken J. Stevens' Fair, 20 June 1961 whole general view, looking West. See Leeson's notebook 9, pages 92-95 for notes

Identifying Very Metal-Rich Stars with Low-Resolution Spectra: Finding Planet-Search Targets

We present empirical calibrations that estimate stellar metallicity, effective temperature and surface gravity as a function of Lick/IDS indices. These calibrations have been derived from a training set of 261 stars for which (1) high-precision measurements of [Fe/H], T_eff and log g have been made using spectral-synthesis analysis of HIRES spectra, and (2) Lick indices have also been measured. Our [Fe/H] calibration, which has precision 0.07 dex, has identified a number of bright (V < 9) metal-rich stars which are now being screened for hot Jupiter-type planets. Using the Yonsei-Yale stellar models, we show that the calibrations provide distance estimates accurate to 20% for nearby stars. This paper outlines the second tier of the screening of planet-search targets by the N2K Consortium, a project designed to identify the stars most likely to harbor extrasolar planets. Discoveries by the N2K Consortium include the transiting hot Saturn HD 149026 b (Sato et al. 2005, astro-ph/0507009) and HD 88133 b (Fischer et al. 2005). See Ammons et al. (2005, In Press) for a description of the first tier of N2K metallicity screening, calibrations using broadband photometry.Comment: Accepted for publication in the Astrophysical Journa

Quasi-linear simulations of inner radiation belt electron pitch angle and energy distributions

“Peculiar” or “butterfly” electron pitch angle distributions (PADs), with minima near 90°, have recently been observed in the inner radiation belt. These electrons are traditionally treated by pure pitch angle diffusion, driven by plasmaspheric hiss, lightning-generated whistlers, and VLF transmitter signals. Since this leads to monotonic PADs, energy diffusion by magnetosonic waves has been proposed to account for the observations. We show that the observed PADs arise readily from two-dimensional diffusion at L = 2, with or without magnetosonic waves. It is necessary to include cross diffusion, which accounts for the relationship between pitch angle and energy changes. The distribution of flux with energy is also in good agreement with observations between 200 keV and 1 MeV, dropping to very low levels at higher energy. Thus, at this location radial diffusion may be negligible at subrelativistic as well as ultrarelativistic energy