608 research outputs found
Electrothermal linear actuator
Converting electric power into powerful linear thrust without generation of magnetic fields is accomplished with an electrothermal linear actuator. When treated by an energized filament, a stack of bimetallic washers expands and drives the end of the shaft upward
Search for exchange-antisymmetric two-photon states
Atomic two-photon J=0 J'=1 transitions are forbidden for
photons of the same energy. This selection rule is related to the fact that
photons obey Bose-Einstein statistics. We have searched for small violations of
this selection rule by studying transitions in atomic Ba. We set a limit on the
probability that photons are in exchange-antisymmetric states:
.Comment: 5 pages, 4 figures, ReVTeX and .eps. Submitted to Phys. Rev. Lett.
Revised version 9/25/9
Transcriptomic analysis of field-droughted sorghum from seedling to maturity reveals biotic and metabolic responses.
Drought is the most important environmental stress limiting crop yields. The C4 cereal sorghum [Sorghum bicolor (L.) Moench] is a critical food, forage, and emerging bioenergy crop that is notably drought-tolerant. We conducted a large-scale field experiment, imposing preflowering and postflowering drought stress on 2 genotypes of sorghum across a tightly resolved time series, from plant emergence to postanthesis, resulting in a dataset of nearly 400 transcriptomes. We observed a fast and global transcriptomic response in leaf and root tissues with clear temporal patterns, including modulation of well-known drought pathways. We also identified genotypic differences in core photosynthesis and reactive oxygen species scavenging pathways, highlighting possible mechanisms of drought tolerance and of the delayed senescence, characteristic of the stay-green phenotype. Finally, we discovered a large-scale depletion in the expression of genes critical to arbuscular mycorrhizal (AM) symbiosis, with a corresponding drop in AM fungal mass in the plants' roots
Precise study of the resonance at Q0=(1,0,0) in URu2Si2
New inelastic neutron scattering experiments have been performed on URu2Si2
with special focus on the response at Q0=(1,0,0), which is a clear signature of
the hidden order (HO) phase of the compound. With polarized inelastic neutron
experiments, it is clearly shown that below the HO temperature (T0 = 17.8 K) a
collective excitation (the magnetic resonance at E0 \approx 1.7 meV) as well as
a magnetic continuum co-exist. Careful measurements of the temperature
dependence of the resonance lead to the observation that its position shifts
abruptly in temperature with an activation law governed by the partial gap
opening and that its integrated intensity has a BCS-type temperature
dependence. Discussion with respect to recent theoretical development is made
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Mobile/portable transuranic waste characterization systems at Los Alamos National Laboratory and a model for their use complex-wide
Los Alamos National Laboratory (LANL) has implemented mobile and portable characterization and repackaging systems to characterize transuranic (TRU) waste in storage for ultimate shipment and disposal at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM. These mobile systems are being used to characterize and repackage waste to meet the full requirements of the WIPP Waste Acceptance Criteria (WAC) and the WIPP Characterization Quality Assurance Program Plan (QAPP). Mobile and portable characterization and repackaging systems are being used to supplement the capabilities and throughputs of existing facilities. Utilization of mobile systems is a key factor that is enabling LANL to (1) reduce its TRU waste work-off schedule from 36 years to 8.5 years; (2) eliminate the need to construct a 200M. Aggressive implementation of mobile and portable systems throughout the Department of Energy complex through a centralized-distributed services model will result in similar advantages complex-wide
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