214 research outputs found
Dielectric Characterization of Non-Conductive Fabrics for Temperature Sensing through Resonating Antenna Structures.
Seamless integration of electronics within clothing is key for further development of efficient and convenient wearable technologies. Therefore, the characterization of textile and fabric materials under environmental changes and other parametric variations is an important requirement. To our knowledge, this paper presents for the first time the evaluation of dielectric characterization over temperature for non-conductive textiles using resonating structures. The paper describes the effects of temperature variations on the dielectric properties of non-conductive fabrics and how this can be derived from the performance effects of a simple microstrip patch antenna. Organic cotton was chosen as the main substrate for this research due to its broad presence in daily clothing. A dedicated measurement setup is developed to allow reliable and repeatable measurements, isolating the textile samples from external factors. This work shows an approximately linear relation between temperature and textile's dielectric constant, giving to fabric-based antennas temperature sensing properties with capability up to 1 degree Celsius at millimeter-wave frequencies
Graphene Inkjet-Printed Ultrawideband Tapered Coplanar-Waveguide Antenna on Kapton Substrate
This paper presents an ultra-wideband graphene antenna with tapered coplanar-waveguide feed. The proposed antenna covers the 2.7-8.2 GHz bandwidth (2.6-10 GHz measured), with two main resonance frequencies at 3.1 and 5.5 gigahertz (3.1 and 5.8 measured). Simulations show a radiation pattern that looks quasi-omnidirectional with a maximum gain limited to 3.15 dBi and efficiency above 84.7%. In order to post-process the graphene ink and to provide flexibility, Kapton Polyimide is used as a substrate. The flexibility, as well as the lightweight and ease in the fabrication of accurate designs, turns this antenna into a suitable candidate for wearable and flexible wireless applications
Soft Graphene-Based Antennas for Ultrawideband Wireless Communication
Ensuring user-friendliness and the seamless integration of technology into the fabric is a key challenge both for academics and industry participants. Thus, textiles that provide a seamless command-oriented user interface, and are capable of wireless communication have been an increasingly popular topic in recent years. In the field of textile antennas, patch antennas either with the use of embroidering techniques, conductive fabrics or inkjet-printing are leading the way over traditional bulky antennas.
However, there are still significant problems in additive antenna fabrication such as the need to use metallic components as the conductive element which quickly becoming corroded and oxidised and also lead to high material costs.
The main objective of this study is to develop graphene-based antennas for smart textiles that push the state-of-the-art in wireless body-centric systems, by utilising traditional textile manufacturing techniques. Hence, this research suggests a graphene-based antenna on a textile substrate, where the conformity of the antenna is highly desirable for wearable and body-centric applications. The designed antenna consists of a coplanar-waveguide-fed planar inverted cone-shaped patch geometry, aiming at ultrawideband antennas that work in a wide spectrum from 3.1 to 10.6GHz
Mechanical barriers and transforming growth factor beta inhibitor on epidural fibrosis in a rabbit laminectomy model
Background: TGF-ÎČ has been described as a mediator of fibrosis and scarring. Several studies achieved reduction
in experimental scarring through the inhibition of TGF-ÎČ. Fibroblasts have been defined as the cell population
originating fibrosis, blocking fibroblast invasion may impair epidural fibrosis appearance. For this purpose,
biocompatible materials used as mechanical barriers and a TGF-ÎČ inhibitor peptide were evaluated in the reduction
of epidural fibrosis.
Methods: A L6 laminectomy was performed in 40 New Zealand white rabbits. Divided into four groups, each
rabbit was assigned to receive either collagen sponge scaffold (CS group), gelatin-based gel (GCP group), P144Âź
(iTGFÎČ group), or left untreated (control group). Four weeks after surgery, cell density, collagen content, and new
bone formation of the scar area were determined by histomorphometry. Two experienced pathologists scored dura
mater adhesion, scar density, and inflammatory infiltrate in a blinded manner.
Results: In all groups, laminectomy site was filled with fibrous tissue and the dura mater presented adhesions. Only
GCP group presented a significant reduction in collagen content and scar density.
Conclusion: GCP treatment reduces epidural fibrosis although did not prevent dura mater adhesion completely
GPS radio sources: new optical observations and an updated master list
* Aims. Identify optical counterparts, address uncertain identifications and
measure previously unknown redshifts of the host galaxies of candidate GPS
radio sources, and study their stellar populations. * Methods. Long slit
spectroscopy and deep optical imaging in the B, V and R bands, obtained with
the Very Large Telescope. * Results. We obtain new redshifts for B0316+161,
B0407-658, B0904+039, B1433-040, and identify the optical counterparts of
B0008-421 and B0742+103. We confirm the previous identification for B0316+161,
B0407-658, B0554-026, and B0904+039, and find that the previous identification
for B0914+114 is incorrect. Using updated published radio spectral information
we classify as non GPS the following sources: B0407-658, B0437-454, B1648+015.
The optical colors of typical GPS sources are consistent with single
instantaneous burst stellar population models but do not yield useful
information on age or metallicity. A new master list of GPS sources is
presented.Comment: 10 pages + GPS master list. Accepeted for publication by A&
Molecular line emission in NGC1068 imaged with ALMA. I An AGN-driven outflow in the dense molecular gas
We investigate the fueling and the feedback of star formation and nuclear
activity in NGC1068, a nearby (D=14Mpc) Seyfert 2 barred galaxy, by analyzing
the distribution and kinematics of the molecular gas in the disk. We have used
ALMA to map the emission of a set of dense molecular gas tracers (CO(3-2),
CO(6-5), HCN(4-3), HCO+(4-3) and CS(7-6)) and their underlying continuum
emission in the central r ~ 2kpc of NGC1068 with spatial resolutions ~
0.3"-0.5" (~ 20-35pc). Molecular line and dust continuum emissions are detected
from a r ~ 200pc off-centered circumnuclear disk (CND), from the
2.6kpc-diameter bar region, and from the r ~ 1.3kpc starburst (SB) ring. Most
of the emission in HCO+, HCN and CS stems from the CND. Molecular line ratios
show dramatic order-of-magnitude changes inside the CND that are correlated
with the UV/X-ray illumination by the AGN, betraying ongoing feedback. The gas
kinematics from r ~ 50pc out to r ~ 400pc reveal a massive (M_mol ~ 2.7 (+0.9,
-1.2) x 10^7 Msun) outflow in all molecular tracers. The tight correlation
between the ionized gas outflow, the radio jet and the occurrence of outward
motions in the disk suggests that the outflow is AGN-driven. The outflow rate
estimated in the CND, dM/dt ~ 63 (+21, -37) Msun yr^-1, is an order of
magnitude higher than the star formation rate at these radii, confirming that
the outflow is AGN-driven. The power of the AGN is able to account for the
estimated momentum and kinetic luminosity of the outflow. The CND mass load
rate of the CND outflow implies a very short gas depletion time scale of <=1
Myr.Comment: Version accepted for publication in A&A (June 4th). Accepted version.
References (3) added and minor typos corrected. 24 pages, 20 figure
Physics of ULIRGs with MUSE and ALMA: The PUMA project: II. Are local ULIRGs powered by AGN: The subkiloparsec view of the 220 GHz continuum
We analyze new high-resolution (400 pc) âŒ220 GHz continuum and CO(2â1) Atacama Large Millimeter Array (ALMA) observations of a representative sample of 23 local (zâ 1 for 70% of the sample. Therefore, this favors the presence of an obscured active galactic nucleus (AGN) in these objects that could dominate the LIR. We also classify the ULIRG nuclei in two groups: (a) compact nuclei (rcontâ<â120 pc) with high mid-infrared excess emission (ÎL6â20âÎŒm/LIR) found in optically classified AGN; and (b) nuclei following a relation with decreasing ÎL6â20âÎŒm/LIR for decreasing rcont. The majority, 60%, of the nuclei in interacting systems lie in the low-rcont end (<120 pc) of this relation, while this is the case for only 30% of the mergers. This suggests that in the early stages of the interaction, the activity occurs in a very compact and dust-obscured region while, in more advanced merger stages, the activity is more extended, unless an optically detected AGN is present. Approximately two-thirds of the nuclei have nuclear radiation pressures above the Eddington limit. This is consistent with the ubiquitous detection of massive outflows in local ULIRGs and supports the importance of the radiation pressure in the outflow launching process
Physics of ULIRGs with MUSE and ALMA: PUMA IV. No tight relation between cold molecular outflow rates and AGN luminosities
We study molecular outflows in a sample of 25 nearby (z< 0.17, d<750 Mpc)
ULIRG systems (38 individual nuclei) as part of the "Physics of ULIRGs with
MUSE and ALMA" (PUMA) survey, using ~400 pc (0.1-1.0" beam FWHM) resolution
ALMA CO(2-1) observations. We used a spectro-astrometry analysis to identify
high-velocity (> 300 km/s) molecular gas disconnected from the galaxy rotation,
which we attribute to outflows. In 77% of the 26 nuclei with , we identifid molecular outflows with an average
km/s, outflow masses , mass
outflow rates yr, mass-loading factors
, and an average outflow mass escape fraction
of 45%. The majority of these outflows (18/20) are spatially resolved with
radii of 0.2-0.9 kpc and have short dynamical times ()
in the range 0.5-2.8 Myr. The outflow detection rate is higher in nuclei
dominated by starbursts (SBs, 14/15=93%) than in active galactic nuclei (AGN,
6/11=55%). Outflows perpendicular to the kinematic major axis are mainly found
in interacting SBs. We also find that our sample does not follow the
versus AGN luminosity relation reported in previous works. In
our analysis, we include a sample of nearby main-sequence galaxies (SFR =
0.3-17 yr) with detected molecular outflows from the
PHANGS-ALMA survey to increase the dynamic range. Using these two
samples, we find a correlation between the outflow velocity and the SFR, as
traced by (, which is consistent
with what was found for the atomic ionised and neutral phases. Using this
correlation, and the relation between and , we
conclude that these outflows are likely momentum-driven.Comment: 27 pages, 23 figures; Appendix: 49 pages, 41 figures. Accepted for
publication in Astronomy & Astrophysic
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