521 research outputs found
Nondestructive testing techniques used in analysis of honeycomb structure bond strength
DOT /Driver-Displacement Oriented Transducer/, applicable to both lap shear type application and honeycomb sandwich structures, measures the displacement of the honeycomb composite face sheet. It incorporates an electromagnetic driver and a displacement measuring system into a single unit to provide noncontact bond strength measurements
1861-11-02 Correspondence between James G. Blaine, Governor Washburn, and Lieutenant Colonel George Varney
https://digitalmaine.com/cw_me_2nd_regiment_corr/1187/thumbnail.jp
Quantum Monte Carlo study of the visibility of one-dimensional Bose-Fermi mixtures
The study of ultracold optically trapped atoms has opened new vistas in the
physics of correlated quantum systems. Much attention has now turned to
mixtures of bosonic and fermionic atoms. A central puzzle is the disagreement
between the experimental observation of a reduced bosonic visibility , and quantum Monte Carlo (QMC) calculations which show
increasing. In this paper, we present QMC simulations which evaluate the
density profiles and of mixtures of bosons and fermions in
one-dimensional optical lattices. We resolve the discrepancy between theory and
experiment by identifying parameter regimes where is reduced, and
where it is increased. We present a simple qualitative picture of the different
response to the fermion admixture in terms of the superfluid and
Mott-insulating domains before and after the fermions are included. Finally, we
show that exhibits kinks which are tied to the domain evolution
present in the pure case, and also additional structure arising from the
formation of boson-fermion molecules, a prediction for future experiments.Comment: 4 pages, 6 figure
Locating the source of projectile fluid droplets
The ill-posed projectile problem of finding the source height from spattered
droplets of viscous fluid is a longstanding obstacle to accident reconstruction
and crime scene analysis. It is widely known how to infer the impact angle of
droplets on a surface from the elongation of their impact profiles. However,
the lack of velocity information makes finding the height of the origin from
the impact position and angle of individual drops not possible. From aggregate
statistics of the spatter and basic equations of projectile motion, we
introduce a reciprocal correlation plot that is effective when the polar launch
angle is concentrated in a narrow range. The vertical coordinate depends on the
orientation of the spattered surface, and equals the tangent of the impact
angle for a level surface. When the horizontal plot coordinate is twice the
reciprocal of the impact distance, we can infer the source height as the slope
of the data points in the reciprocal correlation plot. If the distribution of
launch angles is not narrow, failure of the method is evident in the lack of
linear correlation. We perform a number of experimental trials, as well as
numerical calculations and show that the height estimate is insensitive to
aerodynamic drag. Besides its possible relevance for crime investigation,
reciprocal-plot analysis of spatter may find application to volcanism and other
topics and is most immediately applicable for undergraduate science and
engineering students in the context of crime-scene analysis.Comment: To appear in the American Journal of Physics (ms 23338). Improved
readability and organization in this versio
Structural insights into the calcium-dependent interaction between calbindin-D28K and caspase-3
AbstractThe regulation of apoptosis involves a complicated cascade requiring numerous protein interactions including the pro-apoptotic executioner protein caspase-3 and the anti-apoptotic calcium-binding protein calbindin-D28K. Using isothermal titration calorimetry, we show that calbindin-D28K binds caspase-3 in a Ca2+-dependent fashion. Molecular docking and conformational sampling studies of the Ca2+-loaded capase-3/calbindin-D28K interaction were performed in order to isolate potentially crucial intermolecular contacts. Residues in the active site loops of caspase-3 and EF-hands 1 and 2 of calbindin-D28K were shown to be critical to the interaction. Based on these studies, a model is proposed to help understand how calbindin-D28K may deactivate caspase-3 upon binding.Structured summary of protein interactionsCalbindin-D28K and Caspase-3 bind by isothermal titration calorimetry (View interaction
The Rising Incidence of Type 1 Diabetes Is Accounted for by Cases With Lower-Risk Human Leukocyte Antigen Genotypes
OBJECTIVE—The rising incidence of type 1 diabetes has been attributed to environment, implying a lesser role for genetic susceptibility. However, the rise could be accounted for by either more cases with classic high-risk genes or by cases with other risk genes. Separately, for any degree of genetic susceptibility, age at presentation may decrease in a permissive environment. To examine these possibilities, human leukocyte antigen (HLA) class II DRB1 genes known to confer risk for type 1 diabetes were analyzed in relation to year of birth and age at diagnosis over the last five decades
Acceleressence: Dark Energy from a Phase Transition at the Seesaw Scale
Simple models are constructed for "acceleressence" dark energy: the latent
heat of a phase transition occurring in a hidden sector governed by the seesaw
mass scale v^2/M_Pl, where v is the electroweak scale and M_Pl the
gravitational mass scale. In our models, the seesaw scale is stabilized by
supersymmetry, implying that the LHC must discover superpartners with a
spectrum that reflects a low scale of fundamental supersymmetry breaking.
Newtonian gravity may be modified by effects arising from the exchange of
fields in the acceleressence sector whose Compton wavelengths are typically of
order the millimeter scale. There are two classes of models. In the first class
the universe is presently in a metastable vacuum and will continue to inflate
until tunneling processes eventually induce a first order transition. In the
simplest such model, the range of the new force is bounded to be larger than 25
microns in the absence of fine-tuning of parameters, and for couplings of order
unity it is expected to be \approx 100 microns. In the second class of models
thermal effects maintain the present vacuum energy of the universe, but on
further cooling, the universe will "soon" smoothly relax to a matter dominated
era. In this case, the range of the new force is also expected to be of order
the millimeter scale or larger, although its strength is uncertain. A firm
prediction of this class of models is the existence of additional energy
density in radiation at the eV era, which can potentially be probed in
precision measurements of the cosmic microwave background. An interesting
possibility is that the transition towards a matter dominated era has occurred
in the very recent past, with the consequence that the universe is currently
decelerating.Comment: 10 pages, references adde
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