21,832 research outputs found
Large Area Crop Inventory Experiment (LACIE). Level 3 baseline; LACIE commodity data control plan for JSC
There are no author-identified significant results in this report
Thermotropic Nematic and Smectic Order in Silica Glass Nanochannels
Optical birefringence measurements on a rod-like liquid crystal (8OCB),
imbibed in silica channels (7 nm diameter), are presented and compared to the
thermotropic bulk behavior. The orientational and positional order of the
confined liquid evolves continuously at the paranematic-to-nematic and sizeably
broadened at the nematic-to-smectic order transition, resp., in contrast to the
discontinuous and well-defined second-order character of the bulk transitions.
A Landau-de-Gennes analysis reveals identical strengths of the nematic and
smectic ordering fields (imposed by the walls) and indicates that the smectic
order is more affected by quenched disorder (originating in channel tortuosity
and roughness) than the nematic transition.Comment: 3 pages, 4 figure
Which long-baseline neutrino experiments are preferable?
We discuss the physics of superbeam upgrades, where we focus on T2KK, a NuMI
beam line based experiment NOvA*, and a wide band beam (WBB) experiment
independent of the NuMI beam line. For T2KK, we find that the Japan-Korea
baseline helps resolve parameter degeneracies, but the improvement due to
correlated systematics between the two detectors (using identical detectors) is
only moderate. For an upgrade of NOvA with a liquid argon detector, we
demonstrate that the Ash River site is preferred compared to alternatives, such
as at the second oscillation maximum, and is the optimal site within the U.S.
For a WBB experiment, we find that high proton energies and long decay tunnels
are preferable. We compare water Cherenkov and liquid argon technologies, and
find the break-even point in detector cost at about 4:1. In order to compare
the physics potential of the different experimental configurations, we use the
concept of exposure to normalize the performance. We find that experiments with
WBBs are the best experimental concept. NOvA* could be competitive with
sufficient luminosity. If > 0.01, a WBB experiment can
perform better than a neutrino factory.Comment: 31 pages, 13 figures, 5 tables. Version to appear in PR
Influence of nano confinement on nematic liquid crystals
We explore the nematic ordering of the rod-like liquid crystals 5CB and 6CB,
embedded into parallel-aligned nanochannels in mesoporous silicon and silica
membranes as a function of mean channel radius (4.7<=R <=8.3 nm), and thus
geometrical confinement strength, by optical birefringence measurements in the
infrared region. The orientational order inside the nanochannels results in an
excess birefringence, which is proportional to the nematic order parameter. It
evolves continuously upon cooling with a precursor behavior, typical of a
paranematic state at high temperatures. These observations are compared with
the bulk behavior and analyzed within a phenomenological model. Such an
approach indicates that the strength of the nematic ordering fields sigma is
beyond a critical threshold sigma_c =1/2, that separates discontinuous from
continuous paranematic-to-nematic behavior. In agreement with the predictions
of the phenomenological approach a linear dependency of sigma on the inverse
channel radius is found and we can infer therefrom the critical channel radii,
R_c, separating continuous from discontinuous paranematic-to-isotropic
behavior, for 5CB (12.1 nm) and 6CB (14.0 nm). Our analysis suggests that the
tangential anchoring at the channel walls is of similar strength in mesoporous
silicon and mesoporous silica membranes. A comparison with the bulk phase
behavior reveals that the nematic order in nanoconfinement is significantly
affected by channel wall roughness leading to a reduction of the effective
nematic ordering.Comment: 7 pages, 5 figure
Upgraded experiments with super neutrino beams: Reach versus Exposure
We introduce exposure as a means to making balanced comparisons of the
sensitivities of long-baseline neutrino experiments to a nonzero \theta_{13},
to CP violation and to the neutrino mass hierarchy. We illustrate its use by
comparing the sensitivities of possible upgrades of superbeam experiments,
namely NOvA*, T2KK and experiments with wide band beams. For the proposed
exposures, we find the best nominal CP violation performance for T2KK. For
equal exposures, a wide band beam experiment has the best mass hierarchy
performance. The physics concept on which NOvA* is based has the best potential
for discovering CP violation only for exposures above a threshold value.Comment: 4 pages, 2 figures, 1 table. Version to appear as a Rapid
Communication in PR
- …
