1,695 research outputs found
Writing Electronic Devices on Paper with Carbon Nanotube Ink
The normal paper used in any printer is among the cheapest flexible organic
materials that exist. We demonstrate that we can print on paper high-frequency
circuits tunable with an applied dc voltage. This is possible with the help of
an ink containing functionalized carbon nanotubes and water. After the water is
evaporated from the paper, the nanotubes remain steadily imprinted on paper,
showing a semiconducting behaviour and tunable electrical properties
An international prospective general population-based study of respiratory work disability
Background: Previous cross-sectional studies have shown that job change due to breathing problems at the workplace (respiratory work disability) is common among adults of working age. That research indicated that occupational exposure to gases, dust and fumes was associated with job change due to breathing problems, although causal inferences have been tempered by the cross-sectional nature of previously available data. There is a need for general population-based prospective studies to assess the incidence of respiratory work disability and to delineate better the roles of potential predictors of respiratory work disability.Methods: A prospective general population cohort study was performed in 25 centres in 11 European countries and one centre in the USA. A longitudinal analysis was undertaken of the European Community Respiratory Health Survey including all participants employed at any point since the baseline survey, 6659 subjects randomly sampled and 779 subjects comprising all subjects reporting physician-diagnosed asthma. The main outcome measure was new-onset respiratory work disability, defined as a reported job change during follow-up attributed to breathing problems. Exposure to dusts (biological or mineral), gases or fumes during follow-up was recorded using a job-exposure matrix. Cox proportional hazard regression modelling was used to analyse such exposure as a predictor of time until job change due to breathing problems.Results: The incidence rate of respiratory work disability was 1.2/1000 person-years of observation in the random sample (95% CI 1.0 to 1.5) and 5.7/1000 person-years in the asthma cohort (95% CI 4.1 to 7.8). In the random population sample, as well as in the asthma cohort, high occupational exposure to biological dust, mineral dust or gases or fumes predicted increased risk of respiratory work disability. In the random sample, sex was not associated with increased risk of work disability while, in the asthma cohort, female sex was associated with an increased disability risk (hazard ratio 2.8, 95% CI 1.3 to 5.9).Conclusions: Respiratory work disability is common overall. It is associated with workplace exposures that could be controlled through preventive measures
Galaxy evolution in nearby groups. II. Galaxy evolution in nearby loose groups. II. Photometric and kinematic characterization of USGC U268 and USGC U376 group members in the Leo cloud
We present the photometric and kinematic characterization of two groups, USGC
U268 and USGC U376 located in different regions of the Leo cloud. U268,
composed of 10 catalogued members and 11 new added members, has a small
fraction (~24%) of early-type galaxies (ETGs). U376 has 16 plus 8 new added
members, with ~38% of ETGs. We find the presence of significant substructures
in both groups suggesting that they are likely accreting galaxies. U268 is
located in a more loose environment than U376. For each member galaxy, broad
band integrated and surface photometry have been obtained in far-UV and near-UV
with GALEX, and in u,g, r, i, z (SDSS) bands. H_alpha imaging and 2D high
resolution kinematical data have been obtained using PUMA Scanning Fabry-Perot
interferometer at the 2.12 m telescope in San Pedro M\'artir, (Baja California,
M\'exico). We improved the galaxy classification and we detected morphological
and kinematical distortions that may be connected to either on-going and/or
past interaction/accretion events or environmental induced secular evolution.
U268 appears more active than U376, with a large fraction of galaxies showing
interaction signatures (60% vs. 13%). The presence of bars among late-type
galaxies is ~10% in U268 and ~$29% in U376. The cumulative distribution of (FUV
- NUV) colours of galaxies in U268 is significantly different than that in U376
with galaxies in U268 bluer than those in U376. In the (FUV-r vs. M_r) and
(NUV-r vs. M_r) planes no members of U268 are found in the `red sequence', even
early-type galaxies lie in the `blue sequence' or in the `green valley'. Most
(80%) of the early-type members in U376 inhabits the `red sequence, a large
fraction of galaxies, of different morphological types, are located in the
`green valley', while the `blue sequence' is under-populated with respect to
U268.Comment: 27 pages, 11 figures, 8 tables, accepted for publication in MNRAS
(abridged abstract
A Series of Manganese(III) Salen Complexes as a Result of Team-Based Inquiry in a Transnational Education Programme.
The development of a team-based approach to research-led transnational practical chemistry teaching is described in which a team of five Chinese students on an articulated transnational degree programme, supported by a team of academic and technical staff, carried out a study examining the structural chemistry of a series of manganese(III) salen complexes. A series of four crystallographically characterized manganese(III) salen complexes with ancillary carboxylate ligands are reported here. The carboxylate coordination modes range from the bridging syn-anti ÎŒ2 -ÎșOâ:âÎșO' mode observed in the predominant cyclohexanoate and isobutyrate species, to a capping terminal monodentate mode for the adamantanoate species, and an unusual mixture of bridging and terminal coordination modes observed in a second minor phase of the cyclohexanoate species. The variation on extended structures based on the weakly interacting aliphatic backbones may provide a useful basis for further structural studies
The Arecibo Galaxy Environment Survey III: Observations Toward the Galaxy Pair NGC 7332/7339 and the Isolated Galaxy NGC 1156
Two 5 square degree regions around the NGC 7332/9 galaxy pair and the
isolated galaxy NGC 1156 have been mapped in the 21-cm line of neutral hydrogen
(HI) with the Arecibo L-band Feed Array out to a redshift of ~0.065
km/s) as part of the Arecibo Galaxy Environment Survey. One of the aims of this
survey is to investigate the environment of galaxies by identifying dwarf
companions and interaction remnants; both of these areas provide the potential
for such discoveries. The neutral hydrogen observations were complemented by
optical and radio follow-up observations with a number of telescopes. A total
of 87 galaxies were found, of which 39 (45 per cent) were previously cataloged
and 15 (17 per cent) have prior redshifts. Two dwarf galaxies have been
discovered in the NGC 7332 group and a single dwarf galaxy in the vicinity NGC
1156 . A parallel optical search of the area revealed one further possible
dwarf galaxy near NGC 7332.Comment: 18 pages, 17 figures, uses emulateap
Modelling and Analysis Mobile Systems Using ïżœpi-calculus (EFCP)
Reference passing systems, like mobile and reconïżœgurable
systems are common nowadays. The common feature of such systems is the possibility to form dynamic logical connections between the individual modules. However, such systems are very diïżœcult to verify, as their logical structure is dynamic. Traditionally, decidable fragments of pi-calculus, e.g. the well-known Finite Control Processes (FCP), are used for formal modelling of reference passing systems. Unfortunately, FCPs allow only `global' concurrency between processes, and thus cannot naturally express scenarios involving `local' concurrency inside a process, such as multicast. In this paper we propose Extended Finite Control Processes (EFCP), which are more convenient for practical modelling. Moreover, an almost linear translation of EFCPs to FCPs is developed,
which enables eïżœcient model checking of EFCPs
Extending ballistic graphene FET lumped element models to diffusive devices
In this work, a modified, lumped element graphene field effect device model
is presented. The model is based on the "Top-of-the-barrier" approach which is
usually valid only for ballistic graphene nanotransistors. Proper modifications
are introduced to extend the model's validity so that it accurately describes
both ballistic and diffusive graphene devices. The model is compared to data
already presented in the literature. It is shown that a good agreement is
obtained for both nano-sized and large area graphene based channels. Accurate
prediction of drain current and transconductance for both cases is obtained
A high-strength silicide phase in a stainless steel alloy designed for wear-resistant applications
Wear- and corrosion-resistant hardfacing steels rely on carbon for strengthening. Here, the authors report an ultra-high strength silicide phase that could lead to a new class of silicide-strengthened stainless steels and alternative coatings for nuclear applications
The Intrinsic Shape Distribution of a Sample of Elliptical Galaxies
We apply the dynamical modeling approach of Statler (1994b) to 13 elliptical galaxies from the Davies and Birkinshaw (1988) sample of radio galaxies to derive constraints on their intrinsic shapes and orientations. We develop an iterative Bayesian algorithm to combine these results to estimate the parent shape distribution from which the sample was drawn, under the assumption that this parent distribution has no preferred orientation. In the process we obtain improved estimates for the shapes of individual objects. The parent shape distribution shows a tendency toward bimodality, with peaks at the oblate and prolate limits. Under minimal assumptions about the galaxies' internal dynamics, 35% of the objects would be strongly triaxial (0.2 < T < 0.8). However, the parent distribution is sensitive to the assumed orbit populations in the galaxies. Dynamical configurations in which all galaxies rotate purely about either their long or short axes can be ruled out because they would require the sample to have a strong orientation bias. Configurations in which the mean motion about the short or long axis is either ``disklike''---dropping off away from the symmetry planes---or ``spheroidlike''---remaining roughly constant at a given radius---are equally viable. Spheroidlike rotation in the long-axis or short-axis tube orbits significantly lowers the abundance of prolate or oblate galaxies, respectively. If rotation in ellipticals is generally disklike, then triaxiality is rare; if spheroidlike, triaxiality is common
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