Bostonia. Volume 14

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

Spin Excitations in a Fermi Gas of Atoms

We have experimentally investigated a spin excitation in a quantum degenerate Fermi gas of atoms. In the hydrodynamic regime the damping time of the collective excitation is used to probe the quantum behavior of the gas. At temperatures below the Fermi temperature we measure up to a factor of 2 reduction in the excitation damping time. In addition we observe a strong excitation energy dependence for this quantum statistical effect.Comment: 4 pages, 3 figure

Electron microprobe analysis of silica cells in leaf epidermal cells of Cyperus alternifolius

Electron microprobe analysis was used to examine relative amounts of selected accessory elements (Ca, Mg, K, Na, P, Mn, and Fe) associated with silicon in silica cells in leaf epidermal cells of Cyperus alternifolius . In the leaf epidermal cells, silicon is localised in significant quantities in silica cells and in a few long epidermal cells. Silicon could not be detected in the stomatal apparatuses. The accumulation of significant amounts of silicon in the silica cell appears to retard the accumulation of K and to enhance the accumulation of Ca, Mg, Mn, Fe, and P. Sodium was detected in very small traces in the silica cells. The possible functional significance of the altered deposition patterns for these elements in Cyperus is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43468/1/11104_2005_Article_BF01373462.pd

Observation of anomalous spin-state segregation in a trapped ultra-cold vapor

We observe counter-intuitive spin segregation in an inhomogeneous sample of ultra-cold, non-condensed Rubidium atoms in a magnetic trap. We use spatially selective microwave spectroscopy to verify a model that accounts for the differential forces on two internal spin states. In any simple understanding of the cloud dynamics, the forces are far too small to account for the dramatic transient spin polarizations observed. The underlying mechanism remains to be elucidated.Comment: 5 pages, 3 figure

Annotated bibliography of research in the teaching of English

The committee reviews important research works in the teaching of English that have been published in the last year. Committee members include Richard Beach, Martha Bigelow, Martine Braaksma, Deborah Dillon, Jessie Dockter, Lee Galda, Lori Helman, Tanja Janssen, Karen Jorgensen, Richa Kapoor, Lauren Liang, Bic Ngo, David O’Brien, Mistilina Sato, and Cassie Scharber

Flowsheet development studies for the decontamination of high-activity-level water at Three Mile Island Unit 2

Several chemical processing flowsheets were considered for the decontamination of high-activity-level water at the Three Mile Island (TMI) Unit 2. A zeolite ion exchange process was evaluated and recommended for absorption of the bulk of the highly radioactive cesium and strontium. Standard organic ion-exchange resins were selected to remove the remaining traces of radioactive nuclides (except tritium which cannot be removed by any practical process). Process conditions were evaluated using both synthetic, tracer-level solutions and samples of actual, high-activity level water from TMI Unit 2

From nonwetting to prewetting: the asymptotic behavior of 4He drops on alkali substrates

We investigate the spreading of 4He droplets on alkali surfaces at zero temperature, within the frame of Finite Range Density Functional theory. The equilibrium configurations of several 4He_N clusters and their asymptotic trend with increasing particle number N, which can be traced to the wetting behavior of the quantum fluid, are examined for nanoscopic droplets. We discuss the size effects, inferring that the asymptotic properties of large droplets correspond to those of the prewetting film