Bostonia: The Boston University Alumni Magazine. Volume 37

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Parapholis incurva and Chloris polydactyla in Texas

The establishment of the grass Parapholis incurva (L.) C. E. Hubb. along the Gulf Coast of Texas has been brought to the attention of the writer by recent collections at Port Arthur, Jefferson County (W. J. Waldrip 139), and High Island, Chambers County (F. W. Gould 6770). By coincidence the two collections were made the same day, April 19, 1955, on independent field excursions by members of the Texas A. & M. College, Department of Range and Forestry

Texas Grasses- A Preliminary Checklist.

34 p

Preliminary Investigations of Joining Technologies for Attaching Refractory Metals to Ni-Based Superalloys

In this study, a range of joining technologies has been investigated for creating attachments between refractory metal and Ni-based superalloys. Refractory materials of interest include Mo-47%Re, T-111, and Ta-10%W. The Ni-based superalloys include Hastelloy X and MarM 247. During joining with conventional processes, these materials have potential for a range of solidification and intermetallic formation-related defects. For this study, three non-conventional joining technologies were evaluated. These included inertia welding, electro-spark deposition (ESD) welding, and magnetic pulse welding (MPW). The developed inertia welding practice closely paralleled that typically used for the refractory metals alloys. Metallographic investigations showed that forging during inertia welding occurred predominantly on the nickel base alloy side. It was also noted that at least some degree of forging on the refractory metal side of the joint was necessary to achieve consistent bonding. Both refractory metals were readily weldable to the Hastelloy X material. When bonding to the MarM 247, results were inconsistent. This was related to the higher forging temperatures of the MarM 247, and subsequent reduced deformation on that material during welding. ESD trials using a Hastelloy X filler were successful for all material combinations. ESD places down very thin (5- to 10- m) layers per pass, and interactions between the substrates and the fill were limited (at most) to that layer. For the refractory metals, the fill only appeared to wet the surface, with minimal dilution effects. Microstructures of the deposits showed high weld metal integrity with maximum porosity on the order of a few percent. Some limited success was also obtained with MPW. In these trials, only the T-111 tubes were used. Joints were possible for the T-111 tube to the Hastelloy X bar stock, but the stiffness of the tube (resisting collapse) necessitated the use of very high power levels. These power levels resulted in damage to the equipment (concentrator) during welding. It is of note that the joint made showed the typical wavy bond microstructure associated with magnetic pulse/explosion bond joints. Joints were not possible between the T-111 tube and the MarM 247 bar stock. In this case, the MarM 247 shattered before sufficient impact forces could be developed for bonding

On the effects of domestication on canine social development and behavior

Social development and behavior are compared for 4 Eastern timber wolves (C. lupus lycaon) and 4 Alaskan Malamutes (C. familiaris). The two groups were born a year apart, but all were fostered at approximately 10 days of age on the same lactating female wolf, reared jointly by the authors and the foster mother, housed in the same facility, and subjected to the same regimen of maintenance and social contact with adult members of the animal colony. It is suggested that many of the observed group differences can be attributed to selection in domestic dogs for prolongation of juvenile behavior and morphological characteristics. Discussion then focuses on the evolution and ontogeny of ritualized aggression in wolves and the effects of domestication on agonistic behavior in domestic dogs. It is suggested that the disintegration of ritualized aggression in dogs is, in part, a consequence of neotenization. Also implicated in the breakdown of this behavioral system is human provision of food, which relaxes (1) the behavioral consequences of injuries sustained in fighting and (2) the selective advantage enjoyed by group-hunting species who have evolved social systems of population regulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23918/1/0000163.pd

Constraints on neutrino-photon interactions from rare Z decays

It is shown that the rare decays $Z \to \nu \bar{nu} \gamma$ and $Z \to \nu \bar{\nu} \gamma \gamma$ are useful to put model-independent bounds on neutrino-one-photon and neutrino-two-photon interactions. The results are then used to constrain the $\tau$ neutrino magnetic moment and the double radiative decay $\nu_j \to \nu_i \gamma \gamma$. It is found that the decay $Z \to \nu \bar{nu} \gamma$ gives a more stringent bound on the $\tau$ neutrino magnetic moment than that obtained from $Z \to \nu \bar{\nu} \gamma \gamma$; the latter decay in turn gives limits on the neutrino-two-photon interaction that are less stringent than those obtained for a sterile neutrino $\nu_s$ from the analysis of $\nu_\mu N \to \nu_s N$ conversion.Comment: 11 pages, 5 figures, elsart forma