11,992 research outputs found
A follow-up study of the 1949 and 1950 graduates of Chandler School for Women, Boston, Massachusetts, and a survey of the employers of the Chandler graduates, with implications for curriculum revision.
Thesis (Ed.M.)--Boston Universityb1466393
Transverse Momentum in Semi-Inclusive Polarized Deep Inelastic Scattering and the Spin-Flavor Structure of the Proton
The non-valence spin-flavor structure of the nucleon extracted from
semi-inclusive measurements of polarized deep inelastic scattering depends
strongly on the transverse momentum of the detected hadrons which are used to
determine the individual polarized sea distributions. This physics may explain
the recent HERMES observation of a positively polarized strange sea through
semi-inclusive scattering, in contrast to the negative strange sea polarization
deduced from inclusive polarized deep inelastic scattering.Comment: 4 pages, revtex style, 2 figure
Cation mono- and co-doped anatase TiO nanotubes: An {\em ab initio} investigation of electronic and optical properties
The structural, electronic, and optical properties of metal (Si, Ge, Sn, and
Pb) mono- and co-doped anatase TiO nanotubes are investigated, in order
to elucidate their potential for photocatalytic applications. It is found that
Si doped TiO nanotubes are more stable than those doped with Ge, Sn, or
Pb. All dopants lower the band gap, except the (Ge, Sn) co-doped structure, the
decrease depending on the concentration and the type of dopant.
Correspondingly, a redshift in the optical properties for all kinds of dopings
is obtained. Even though a Pb mono- and co-doped TiO nanotube has the
lowest band gap, these systems are not suitable for water splitting, due to the
location of the conduction band edges, in contrast to Si, Ge, and Sn mono-doped
TiO nanotubes. On the other hand, co-doping of TiO does not improve
its photocatalytic properties. Our findings are consistent with recent
experiments which show an enhancement of light absorption for Si and Sn doped
TiO nanotubes.Comment: revised and updated, 23 pages (preprint style), 7 figures, 5 table
Determination of the - mixing angle
We extract - mixing angle and the ratios of decay
constants of light pseudoscalar mesons , and using
recently available BaBar measurements on -photon and -photon
transition form factors and more accurate experimental data for the masses and
two-photon decay widths of the light pseduoscalar mesons.Comment: 5 pages, revtex, no figures, accepted for publication as a Brief
Report in Physical Review
CONFIGURATION-INDEPENDENT ELASTIC INTERACTIONS IN METAL HYDROGEN SOLUTIONS
The authors demonstrate quantitative methods for estimating that part of the elastic interaction energy between defects in solids which does not depend on the precise spatial arrangement of the defects. This energy involves both the total volume change per defect in the finite solid and the purely shear part of the volume change. Several different continuum and atomistic modelling methods are used to calculate these volume changes for H in Pd, V, Nb and Ta. An estimate of the configuration-independent elastic interaction energy is made for the Pd-H system as a function of the H concentration, and is given in a form suitable for comparison with statistical models
Heavy-ion interaction potential deduced from density-constrained TDHF calculation
We present a new method for calculating the heavy-ion interaction potential
from a density-constrained time-dependent Hartree-Fock calculation.Comment: 4 pages, 3 figure
A gas flow indicator for portable life support systems
A three-part program was conducted to develop a gas flow indicator (GFI) to monitor ventilation flow in a portable life support system. The first program phase identified concepts which could potentially meet the GFI requirements. In the second phase, a working breadboard GFI, based on the concept of a pressure sensing diaphragm-aneroid assembly connected to a venturi, was constructed and tested. Extensive testing of the breadboard GFI indicated that the design would meet all NASA requirements including eliminating problems experienced with the ventilation flow sensor used in the Apollo program. In the third program phase, an optimized GFI was designed by utilizing test data obtained on the breadboard unit. A prototype unit was constructed using prototype materials and fabrication techniques, and performance tests indicated that the prototype GFI met or exceeded all requirements
Applications of elastic-viscoplastic constitutive models in dynamic analyses of crack run-arrest events
Applications of nonlinear techniques to the first series of six HSST wide-plate crack-arrest tests that were performed are described. The experiments include crack initiations at low temperatures and relatively long (20 cm) cleavage propagation phases which are terminated by arrest in high temperature regions. Crack arrest are then followed by ductile tearing events. Consequently, the crack front regions are exposed to wide ranges of strain rates and temperatures
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