8,318 research outputs found
Motion cue effects on human pilot dynamics in manual control
Two experiments were conducted to study the motion cue effects on human pilots during tracking tasks. The moving-base simulator of National Aerospace Laboratory was employed as the motion cue device, and the attitude director indicator or the projected visual field was employed as the visual cue device. The chosen controlled elements were second-order unstable systems. It was confirmed that with the aid of motion cues the pilot workload was lessened and consequently the human controllability limits were enlarged. In order to clarify the mechanism of these effects, the describing functions of the human pilots were identified by making use of the spectral and the time domain analyses. The results of these analyses suggest that the sensory system of the motion cues can yield the differential informations of the signal effectively, which coincides with the existing knowledges in the physiological area
Electron paramagnetic resonance, optical absorption and Raman spectral studies on a pyrite/chalcopyrite mineral
Pyrite and chalcopyrite mineral samples from Mangampet barite mine, Kadapa, Andhra Pradesh, India are used in the present study. XRD data indicate that the pyrite mineral has a face centered cubic lattice structure with lattice constant 5.4179 Ã…. Also it possesses an average particle size of 91.9 nm. An EPR study on the powdered samples confirms the presence of iron in pyrite and iron and Mn(II) in chalcopyrite. The optical absorption spectrum of chalcopyrite indicates presence of copper which is in a distorted octahedral environment. NIR results confirm the presence of water fundamentals and Raman spectrum reveals the presence of water and sulfate ions
Higgs Mass and Muon Anomalous Magnetic Moment in Supersymmetric Models with Vector-Like Matters
We study the muon anomalous magnetic moment (muon g-2) and the Higgs boson
mass in a simple extension of the minimal supersymmetric (SUSY) Standard Model
with extra vector-like matters, in the frameworks of gauge mediated SUSY
breaking (GMSB) models and gravity mediation (mSUGRA) models. It is shown that
the deviation of the muon g-2 and a relatively heavy Higgs boson can be
simultaneously explained in large tan-beta region. (i) In GMSB models, the
Higgs mass can be more than 135 GeV (130 GeV) in the region where muon g-2 is
consistent with the experimental value at the 2 sigma (1 sigma) level, while
maintaining the perturbative coupling unification. (ii) In the case of mSUGRA
models with universal soft masses, the Higgs mass can be as large as about 130
GeV when muon g-2 is consistent with the experimental value at the 2 sigma
level. In both cases, the Higgs mass can be above 140 GeV if the g-2 constraint
is not imposed.Comment: 26 pages; 7 figures; corrected typos; minor change
Collapsing transition of spherical tethered surfaces with many holes
We investigate a tethered (i.e. fixed connectivity) surface model on
spherical surfaces with many holes by using the canonical Monte Carlo
simulations. Our result in this paper reveals that the model has only a
collapsing transition at finite bending rigidity, where no surface fluctuation
transition can be seen. The first-order collapsing transition separates the
smooth phase from the collapsed phase. Both smooth and collapsed phases are
characterized by Hausdorff dimension H\simeq 2, consequently, the surface
becomes smooth in both phases. The difference between these two phases can be
seen only in the size of surface. This is consistent with the fact that we can
see no surface fluctuation transition at the collapsing transition point. These
two types of transitions are well known to occur at the same transition point
in the conventional surface models defined on the fixed connectivity surfaces
without holes.Comment: 7 pages with 11 figure
Cosmological evolution of scalar fields and gravitino dark matter in gauge mediation at low reheating temperatures
We consider the dynamics of the supersymmetry-breaking scalar field and the
production of dark matter gravitinos via its decay in a gauge-mediated
supersymmetry breaking model with metastable vacuum. We find that the scalar
field amplitude and gravitino density are extremely sensitive to the parameters
of the hidden sector. For the case of an O'Raifeartaigh sector, we show that
the observed dark matter density can be explained by gravitinos even for low
reheating temperatures T_{R} < 10 GeV. Such low reheating temperatures may be
implied by detection of the NLSP at the LHC if its thermal freeze-out density
is in conflict with BBN.Comment: 11 pages RevTex. Extended discussion and minor corrections,
conclusions unaltered. Version to be published in JCA
3D Dune Skeleton Model as a Coupled Dynamical System of 2D Cross-Sections
To analyze theoretically the stability of the shape and the migration process
of transverse dunes and barchans, we propose a {\it skeleton model} of 3D dunes
described with coupled dynamics of 2D cross-sections. First, 2D cross-sections
of a 3D dune parallel to the wind direction are extracted as elements of a
skeleton of the 3D dune, hence, the dynamics of each and interaction between
them is considered. This model simply describes the essential dynamics of 3D
dunes as a system of coupled ordinary differential equations. Using the model
we study the stability of the shape of 3D transversal dunes and their
deformation to barchans depending on the amount of available sand in the dune
field, sand flow in parallel and perpendicular to wind direction.Comment: 6 pages, 6 figures, lette
First-principles study on scanning tunneling microscopy images of hydrogen-terminated Si(110) surfaces
Scanning tunneling microscopy images of hydrogen-terminated Si(110) surfaces
are studied using first-principles calculations. Our results show that the
calculated filled-state images and local density of states are consistent with
recent experimental results, and the empty-state images appear significantly
different from the filled-state ones. To elucidate the origin of this
difference, we examined in detail the local density of states, which affects
the images, and found that the bonding and antibonding states of surface
silicon atoms largely affect the difference between the filled- and empty-state
images.Comment: 4 pages, and 4 figure
Light Higgsino in Heavy Gravitino Scenario with Successful Electroweak Symmetry Breaking
We consider, in the context of the minimal supersymmetric standard model, the
case where the gravitino weighs 10^6 GeV or more, which is preferred by various
cosmological difficulties associated with unstable gravitinos. Despite the
large Higgs mixing parameter B together with the little hierarchy to other soft
supersymmetry breaking masses, a light higgsino with an electroweak scale mass
leads to successful electroweak symmetry breaking, at the price of fine-tuning
the higgsino mixing mu parameter. Furthermore the light higgsinos produced at
the decays of gravitinos can constitute the dark matter of the universe. The
heavy squark mass spectrum of O(10^4) GeV can increase the Higgs boson mass to
about 125 GeV or higher.Comment: 13 pages, 3 figures; v2: version to appear in JHE
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