Statistics of associations among IR galaxies

In the course of expanding the search of Kleinmann et. al. (1988) for distant, infrared-luminous objects, the authors noticed (as is often remarked) that a large number of infrared-selected galaxies have close neighbors or show merger characteristics (e.g., tidal tails, distorted disks). Because the sample size is large (567 infrared galaxies and 2182 field galaxies), this sample is ideal for statistically examining the importance of interactions among infrared galaxies. In particular, the authors compare the nearest-neighbor distribution and the two-point correlation function of their sample with that of a control sample of field galaxies

On-the-Job Communications in the Engineering Department at the New England Corporation

Thesis (M.B.A)--Boston Universit

EFFECTS OF INCREASING PANAMA CANAL TOLL RATES ON U.S. GRAIN EXPORTS

Some believe Panama Canal toll rates will increase dramatically as Panama's sovereignty over the Canal becomes complete at the end of this century. This paper focuses on the ability of Panama Canal management to extract additional toll revenues from United States grain traversing the Canal and the impact of increased toll rates on export grain flows. Analyses show toll rates established by a revenue-maximizing Canal management would exceed historical and current rates. A monopolizing Canal operator would have moderately increased Pacific port exports in the mid-1970Â’s; whereas, in the 1979-82 period, Pacific port flows would have exceeded historical levels.International Relations/Trade,

To Argos: Archaeological Survey in the Western Argolid, 2014-2016

The Western Argolid Regional Project (WARP) completed three seasons of intensive pedestrian survey from 2014 to 2016. Conducted under the auspices of the Canadian Institute in Greece (CIG) and the Ephorate of Antiquities of the Argolid, WARP is an interdisciplinary project focused around the upper valleys of the Inachos River to the north and west of Argos. The project aims to address a lacuna in our knowledge of the northeastern Peloponnese since, despite over a century of excavation and survey in the Argolid, little is known about the relationship between Argos and its countryside

Plasma properties downstream of a low-power Hall thruster

Triple Langmuir probes and emissive probes were used to measure the electron number density, electron temperature, and plasma potential downstream of a low-power Hall thruster. The results show a polytropic relation between electron temperature and electron number density throughout the sampled region. Over a large fraction of the plume, the plasma potential obeys the predictions of ambipolar expansion. Near the thruster centerline, however, observations show larger gradients of plasma potential than can be accounted for by this means. Radial profiles of plasma potential in the very-near-field plume are shown to contain large gradients that correspond in location to the boundaries of a visually intense plasma region.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87761/2/123503_1.pd

Preliminary Plume Characterization of a Low-Power Hall Thruster Cluster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76481/1/AIAA-2002-4251-381.pd

The Effects of Cathode Configuration on Hall Thruster Cluster Plume Properties

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76110/1/AIAA-2005-3678-895.pd

The design of a cathode to operate in an oxygen-rich environment

The primary problem with Hall plasma accelerator operation on oxygen is poor cathode performance and short lifetime. The primary problem with micro Hall thrusters is the absence of a stable low power cathode. Cathodes traditionally used for both applications employ thermionic emitters which are not efficient and which are easily oxidized in an oxygen-rich environment. The field emitter cathode presented in this report has the potential of filling both vacancies since it does not require a high-power heater and can be scaled down with the size of the thruster. The advantages to using Hf and HfC as emitting materials are low work functions and high resistance to oxygen poisoning. Preliminary investigations proved that HfC emitters can operate in 7.6 mTorr oxygen pressure environments. The initial cathode design employs an electrostatic lens that also acts as an ion filter to prevent thruster ions from bombarding the field emitters while decelerating the electron beam and keeping it focused to ensure efficient performance. Electron trajectories through the cathode and ion filtering capabilities are presented in this report as predicted by the charged particle code, MAGIC. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87392/2/305_1.pd

The Antiferromagnetic Band Structure of La2CuO4 Revisited

Using the Becke-3-LYP functional, we have performed band structure calculations on the high temperature superconductor parent compound, La2CuO4. Under the restricted spin formalism (rho(alpha) equal to rho(beta)), the R-B3LYP band structure agrees well with the standard LDA band structure. It is metallic with a single Cu x2-y2/O p(sigma) band crossing the Fermi level. Under the unrestricted spin formalism (rho(alpha) not equal to rho(beta)), the UB3LYP band structure has a spin polarized antiferromagnetic solution with a band gap of 2.0 eV, agreeing well with experiment. This state is 1.0 eV (per formula unit) lower than that calculated from the R-B3LYP. The apparent high energy of the spin restricted state is attributed to an overestimate of on-site Coulomb repulsion which is corrected in the unrestricted spin calculations. The stabilization of the total energy with spin polarization arises primarily from the stabilization of the x2-y2 band, such that the character of the eigenstates at the top of the valence band in the antiferromagnetic state becomes a strong mixture of Cu x2-y2/O p(sigma) and Cu z2/O' p(z). Since the Hohenberg-Kohn theorem requires the spin restricted and spin unrestricted calculations give exactly the same ground state energy and total density for the exact functionals, this large disparity in energy reflects the inadequacy of current functionals for describing the cuprates. This calls into question the use of band structures based on current restricted spin density functionals (including LDA) as a basis for single band theories of superconductivity in these materials.Comment: 13 pages, 8 figures, to appear in Phys. Rev. B, for more information see http://www.firstprinciples.co