12,180 research outputs found
Exploring relationships between touch perception and surface physical properties
This paper reports a study of materials for confectionery packaging. The aim was to explore the touch perceptions of textures and identify their relationships with the surfaces' physical properties. Thirty-seven tactile textures were tested including 22 cardboards, nine flexible materials and six laminate boards. Semantic differential questionnaires were administered to assess responses to touching the textures against six word pairs: warm-cold, slippery-sticky, smooth,-rough, hard-soft, bumpy-flat, and wet-dry. Four physical measurements were conducted to characterize the surfaces' roughness, compliance, friction, and the rate of cooling of an artificial finger when touching the surface. Correlation and regression analyses were carried out to identify the relationships between the people's responses and the physical measurements. Results show that touch perception is often associated with more than one physical property, and the strength and form of the combined contribution can be represented by a regression model. © 2009 Chen, Shao, Barnes, Childs, & Henson
Statefinder Parameters for Tachyon Dark Energy Model
In this paper we study the statefinder parameters for the tachyon dark energy
model. There are two kinds of stable attractor solutions in this model. The
statefinder diagrams characterize the properties of the tachyon dark energy
model. Our results show that the evolving trajectories of the attractor
solutions lie in the total region and pass through the LCDM fixed point, which
is different from other dark energy model.Comment: 5 pages, 5 figures, accepted by MPL
Recommended from our members
Ambient CFCs and HCFC-22 observed concurrently at 84 sites in the Pearl River Delta region during the 2008–2009 grid studies
Air samples were collected concurrently at 05:00 A.M. and 10:00 A.M. local Beijing time (geomagnetic time + 8) at 84 sites during two grid-study campaigns on 29 September 2008 and 1 March 2009 in the Pearl River Delta region, in order to offer snapshots of ambient CFCs and hydrochlorofluorocarbons (HCFCs) in different seasons and to indicate the presence of local emission sources. Compared to the subtropical northern hemisphere background levels, mean mixing ratios of CFC-11, CFC-12, CFC-113, CFC-114, and HCFC-22 were enhanced by 7%–11%, 8%–11%, 5%–6%, 8%–9%, and 71%–135%, respectively. When data from this tudy were pooled together with previous observations in the region, ambient CFC-11, CFC-12, and CFC-113 unambiguously showed declines in mixing ratios, while HCFC-22 showed an increase. Spatial variations revealed potential emission hot spots in the region, and levels of CFCs and HCFC-22 were higher in September than in March due to many more refrigeration and air-conditioning activities during summer. Source apportioning by positive matrix factorization revealed that new input of CFCs and HCFC-22 into the ambient air was largely attributed to emission from air-conditioning and refrigerating activities instead of industry activities. Average emissions in the region estimated by the CO-tracer method were 0.8 ± 0.2, 1.4 ± 0.6, 0.2 ± 0.1, 0.1 ± 0.02, and 4.4 ± 1.0 Gg/yr for CFC-11, CFC-12, CFC-113, CFC-114, and HCFC-22, respectively, and they accounted for 5.5%–25.5% of the total estimated CFC and HCFC-22 emissions in China
Comparing the Host Galaxies of Type Ia, Type II and Type Ibc Supernovae
We compare the host galaxies of 902 supernovae, including SNe Ia, SNe II and
SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog with
the SDSS Data Release 7. We further selected 213 galaxies by requiring the
light fraction of spectral observations 15%, which could represent well the
global properties of the galaxies. Among them, 135 galaxies appear on the
Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in
terms of star-forming, AGNs (including composites, LINERs and Seyfert 2s) and
"Absorp" (their related emission-lines are weak or non-existence) galaxies. The
diagrams related to parameters D(4000), H, stellar masses, SFRs
and specific SFRs for the SNe hosts show that almost all SNe II and most of SNe
Ibc occur in SF galaxies, which have a wide range of stellar mass and low
D(4000). The SNe Ia hosts as SF galaxies follow similar trends. A
significant fraction of SNe Ia occurs in AGNs and Absorp galaxies, which are
massive and have high D(4000). The stellar population analysis from
spectral synthesis fitting shows that the hosts of SNe II have a younger
stellar population than hosts of SNe Ia. These results are compared with those
of the 689 comparison galaxies where the SDSS fiber captures less than 15% of
the total light. These comparison galaxies appear biased towards higher
12+log(O/H) (0.1dex) at a given stellar mass. Therefore, we believe the
aperture effect should be kept in mind when the properties of the hosts for
different types of SNe are discussed.Comment: 15 pages, 9 figure
Hadron-quark phase transition in asymmetric matter with dynamical quark masses
The two-Equation of State (EoS) model is used to describe the hadron-quark
phase transition in asymmetric matter formed at high density in heavy-ion
collisions. For the quark phase, the three-flavor Nambu--Jona-Lasinio (NJL)
effective theory is used to investigate the influence of dynamical quark mass
effects on the phase transition. At variance to the MIT-Bag results, with fixed
current quark masses, the main important effect of the chiral dynamics is the
appearance of an End-Point for the coexistence zone. We show that a first order
hadron-quark phase transition may take place in the region T=(50-80)MeV and
\rho_B=(2-4)\rho_0, which is possible to be probed in the new planned
facilities, such as FAIR at GSI-Darmstadt and NICA at JINR-Dubna. From isospin
properties of the mixed phase somepossible signals are suggested. The
importance of chiral symmetry and dynamical quark mass on the hadron-quark
phase transition is stressed. The difficulty of an exact location of
Critical-End-Point comes from its appearance in a region of competition between
chiral symmetry breaking and confinement, where our knowledge of effective QCD
theories is still rather uncertain.Comment: 13 pages, 16 figures (revtex
Generation of ELF waves during HF heating of the ionosphere at midlatitudes
Modulated high frequency radio frequency heating of the ionospheric F-region produces a local modulation of the electron temperature, and the resulting pressure gradient gives rise to a diamagnetic current. The oscillations of the diamagnetic current excite hydromagnetic waves in the ELF range that propagate away from the heated region. The generation of the waves in the 2 - 10 Hz range by a modulated heating in the midlatitude ionosphere is studied using numerical simulations of a collisional Hall-magnetohydrodynamic model. To model the plasma processes in the midlatitude ionosphere the Earth's dipole magnetic field and typical ionospheric plasma parameters are used. As the hydromagnetic waves propagate away from the heated region in the F-region, the varying plasma conditions lead to changes in their characteristics. Magnetosonic waves generated in the heating region and propagating down to the E-region, where the Hall conductivity is dominant, excite oscillating Hall currents that produce shear Alfvén waves propagating along the field lines into the magnetosphere, where they propagate as the electromagnetic ion cyclotron (EMIC) and whistler waves. The EMIC waves propagate to the ion cyclotron resonance layer in the magnetosphere, where they are absorbed
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