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Manipulating nanoscale structure to control functionality in printed organic photovoltaic, transistor and bioelectronic devices.
Printed electronics is simultaneously one of the most intensely studied emerging research areas in science and technology and one of the fastest growing commercial markets in the world today. For the past decade the potential for organic electronic (OE) materials to revolutionize this printed electronics space has been widely promoted. Such conviction in the potential of these carbon-based semiconducting materials arises from their ability to be dissolved in solution, and thus the exciting possibility of simply printing a range of multifunctional devices onto flexible substrates at high speeds for very low cost using standard roll-to-roll printing techniques. However, the transition from promising laboratory innovations to large scale prototypes requires precise control of nanoscale material and device structure across large areas during printing fabrication. Maintaining this nanoscale material control during printing presents a significant new challenge that demands the coupling of OE materials and devices with clever nanoscience fabrication approaches that are adapted to the limited thermodynamic levers available. In this review we present an update on the strategies and capabilities that are required in order to manipulate the nanoscale structure of large area printed organic photovoltaic (OPV), transistor and bioelectronics devices in order to control their device functionality. This discussion covers a range of efforts to manipulate the electroactive ink materials and their nanostructured assembly into devices, and also device processing strategies to tune the nanoscale material properties and assembly routes through printing fabrication. The review finishes by highlighting progress in printed OE devices that provide a feedback loop between laboratory nanoscience innovations and their feasibility in adapting to large scale printing fabrication. The ability to control material properties on the nanoscale whilst simultaneously printing functional devices on the square metre scale is prompting innovative developments in the targeted nanoscience required for OPV, transistor and biofunctional devices
The DiskMass Survey. X. Radio synthesis imaging of spiral galaxies
We present results from 21 cm radio synthesis imaging of 28 spiral galaxies
from the DiskMass Survey obtained with the VLA, WSRT, and GMRT facilities. We
detail the observations and data reduction procedures and present a brief
analysis of the radio data. We construct 21 cm continuum images, global HI
emission-line profiles, column-density maps, velocity fields, and
position-velocity diagrams. From these we determine star formation rates
(SFRs), HI line widths, total HI masses, rotation curves, and
azimuthally-averaged radial HI column-density profiles. All galaxies have an HI
disk that extends beyond the readily observable stellar disk, with an average
ratio and scatter of R_{HI}/R_{25}=1.35+/-0.22, and a majority of the galaxies
appear to have a warped HI disk. A tight correlation exists between total HI
mass and HI diameter, with the largest disks having a slightly lower average
column density. Galaxies with relatively large HI disks tend to exhibit an
enhanced stellar velocity dispersion at larger radii, suggesting the influence
of the gas disk on the stellar dynamics in the outer regions of disk galaxies.
We find a striking similarity among the radial HI surface density profiles,
where the average, normalized radial profile of the late-type spirals is
described surprisingly well with a Gaussian profile. These results can be used
to estimate HI surface density profiles in galaxies that only have a total HI
flux measurement. We compare our 21 cm radio continuum luminosities with 60
micron luminosities from IRAS observations for a subsample of 15 galaxies and
find that these follow a tight radio-infrared relation, with a hint of a
deviation from this relation at low luminosities. We also find a strong
correlation between the average SFR surface density and the K-band surface
brightness of the stellar disk.Comment: 22 pages + Appendix, 16 figures + Atlas, 5 tables. Accepted for
publication in Astronomy & Astrophysic
The DiskMass Survey. VIII. On the Relationship Between Disk Stability and Star Formation
We study the relationship between the stability level of late-type galaxy
disks and their star-formation activity using integral-field gaseous and
stellar kinematic data. Specifically, we compare the two-component (gas+stars)
stability parameter from Romeo & Wiegert (Q_RW), incorporating stellar
kinematic data for the first time, and the star-formation rate estimated from
21cm continuum emission. We determine the stability level of each disk
probabilistically using a Bayesian analysis of our data and a simple dynamical
model. Our method incorporates the shape of the stellar velocity ellipsoid
(SVE) and yields robust SVE measurements for over 90% of our sample. Averaging
over this subsample, we find a meridional shape of sigma_z/sigma_R =
0.51^{+0.36}_{-0.25} for the SVE and, at 1.5 disk scale lengths, a stability
parameter of Q_RW = 2.0 +/- 0.9. We also find that the disk-averaged
star-formation-rate surface density (Sigma-dot_e,*) is correlated with the
disk-averaged gas and stellar mass surface densities (Sigma_e,g and Sigma_e,*)
and anti-correlated with Q_RW. We show that an anti-correlation between
Sigma-dot_e,* and Q_RW can be predicted using empirical scaling relations, such
that this outcome is consistent with well-established statistical properties of
star-forming galaxies. Interestingly, Sigma-dot_e,* is not correlated with the
gas-only or star-only Toomre parameters, demonstrating the merit of calculating
a multi-component stability parameter when comparing to star-formation
activity. Finally, our results are consistent with the Ostriker et al. model of
self-regulated star-formation, which predicts
Sigma-dot_e,*/Sigma_e,g/sqrt(Sigma_e,*). Based on this and other theoretical
expectations, we discuss the possibility of a physical link between disk
stability level and star-formation rate in light of our empirical results.Comment: Accepted for publication in ApJ. 15 pages, 6 figures, 2 tables. An
electronic version of Table 1 is available by request, or at
http://www.astro.rug.nl/~westfall/research/dmVIII_table1.tx
Separation of Long-Crested Nonlinear Bichromatic Waves into Incident and Reflected Components
Methods for the separation of long-crested linear waves into incident and reflected waves
have existed for more than 40 years. The present paper presents a new method for the separation
of nonlinear bichromatic long-crested waves into incident and reflected components, as well as
into free and bound components. The new method is an extension of a recently proposed method
for the separation of nonlinear regular waves. The new methods include both bound and free
higher harmonics, which is important for nonlinear waves. The applied separation method covers
interactions to the third order, but can easily be extended to a higher orders. Synthetic tests, as well as
physical model tests, showed that the method accurately predict the bound amplitudes and incident
and reflected surface elevations of nonlinear bichromatic waves. The new method is important
in order to be able to describe the detailed characteristics of nonlinear bichromatic waves and
their reflection
Method of Reducing Odor Associated with Hexanal Production in Plant Products
A method of reducing the formation of hexanal by plant parts comprises breaking the plant parts, adding thereto an agent comprising lipoxygenase 3 enzyme and allowing the plant parts to remain in contact with the enzyme under conditions effective to attain the desired effect. A method of producing a low odor plant part meal or flour comprises breaking up the plant parts, adding an agent with lipoxygenase 3 enzyme and allowing the plant parts to remain in contact with the enzyme under conditions effective to attain the desired effect. An improved composition comprises a hexanal producing plant part meal or flour and an agent with lipoxygenase 3 enzyme which is substantially devoid of lipoxygenase enzyme 1 and 2 activities, optionally with other edible ingredients such as other low-hexanal producing flours. Improved edible products are produced using the invention which have less objectionable odor and flavor. This invention facilitates better tailoring of the flavor of food products to the desires of the consumers
Multi-decadal atmospheric and marine climate variability in southern Iberia during the mid- to late-Holocene
To assess the regional multi-decadal to multicentennial climate variability along the southern Iberian Peninsula during the mid- to late-Holocene record of paleoenvironmental indicators from marine sediments were established for two sites in the Alboran Sea (ODP-161-976A) and the Gulf of Cadiz (GeoB5901-2). High-resolution records of organic geochemical properties and planktic foraminiferal assemblages are used to decipher precipitation and vegetation changes as well as hydrological conditions with respect to sea surface temperature (SST) and marine primary productivity (MPP). As a proxy for precipitation change, records of plant-derived n-alkane composition suggest a series of five distinct dry episodes in southern Iberia at 5.4 +/- 0.3 ka cal BP, from 5.1 to 4.9 +/- 0.1 ka cal BP, from 4.8 to 4.7 +/- 0.1 ka cal BP, from 4.4 to 4.3 +/- 0.1 ka cal BP, and at 3.7 +/- 0.1 ka cal BP. During each dry episode the vegetation suffered from reduced water availability. Interestingly, the dry phase from 4.4 to 4.3 +/- 0.1 ka cal BP is followed by a rapid shift towards wetter conditions revealing a more complex pattern in terms of its timing and duration than was described for the 4.2 ka event in other regions. The series of dry episodes as well as closely connected hydrological variability in the Alboran Sea were probably driven by NAO-like (North Atlantic Oscillation) variability. In contrast, surface waters in the Gulf of Cadiz appear to have responded more directly to North Atlantic cooling associated with Bond events. In particular, during Bond events 3 and 4, a pronounced increase in seasonality with summer warming and winter cooling is found.DFG (German Research Foundation)
CRC 1266
2901391021
Fundacao para a Ciencia e Tecnologia
SFRH/BPD/111433/2015info:eu-repo/semantics/publishedVersio
The DiskMass Survey. II. Error Budget
We present a performance analysis of the DiskMass Survey. The survey uses
collisionless tracers in the form of disk stars to measure the surface-density
of spiral disks, to provide an absolute calibration of the stellar
mass-to-light ratio, and to yield robust estimates of the dark-matter halo
density profile in the inner regions of galaxies. We find a disk inclination
range of 25-35 degrees is optimal for our measurements, consistent with our
survey design to select nearly face-on galaxies. Uncertainties in disk
scale-heights are significant, but can be estimated from radial scale-lengths
to 25% now, and more precisely in the future. We detail the spectroscopic
analysis used to derive line-of-sight velocity dispersions, precise at low
surface-brightness, and accurate in the presence of composite stellar
populations. Our methods take full advantage of large-grasp integral-field
spectroscopy and an extensive library of observed stars. We show that the
baryon-to-total mass fraction (F_b) is not a well-defined observational
quantity because it is coupled to the halo mass model. This remains true even
when the disk mass is known and spatially-extended rotation curves are
available. In contrast, the fraction of the rotation speed supplied by the disk
at 2.2 scale lengths (disk maximality) is a robust observational indicator of
the baryonic disk contribution to the potential. We construct the error-budget
for the key quantities: dynamical disk mass surface-density, disk stellar
mass-to-light ratio, and disk maximality (V_disk / V_circular). Random and
systematic errors in these quantities for individual galaxies will be ~25%,
while survey precision for sample quartiles are reduced to 10%, largely devoid
of systematic errors outside of distance uncertainties.Comment: To appear in ApJ; 88 pages, 4 tables, 18 figures. High-resolution
version available at
http://www.astro.wisc.edu/~mab/publications/DMS_II_preprint.pd
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