Effects of different needles and substrates on CuInS2 deposited by electrostatic spray deposition

Copper indium disulphide (CuInS2) thin films were deposited using the electrostatic spray deposition method. The effects of applied voltage and solution flow rate on the aerosol cone shape, film composition, surface morphology and current conversion were investigated. The effect of aluminium substrates and transparent fluorine doped tin oxide (SnO2:F) coated glass substrates on the properties of as-deposited CuInS2 films were analysed. An oxidation process occurs during the deposition onto the metallic substrates which forms an insulating layer between the photoactive film and substrate. The effects of two different spray needles on the properties of the as-deposited films were also studied. The results reveal that the use of a stainless steel needle results in contamination of the film due to the transfer of metal impurities through the spray whilst this is not seen for the glass needle. The films were characterised using a number of different analytical techniques such as X-ray diffraction, scanning electron microscopy, Rutherford back-scattering and secondary ion mass spectroscopy and opto-electronic measurements

TRAPHIC - Radiative Transfer for Smoothed Particle Hydrodynamics Simulations

We present TRAPHIC, a novel radiative transfer scheme for Smoothed Particle Hydrodynamics (SPH) simulations. TRAPHIC is designed for use in simulations exhibiting a wide dynamic range in physical length scales and containing a large number of light sources. It is adaptive both in space and in angle and can be employed for application on distributed memory machines. The commonly encountered computationally expensive scaling with the number of light sources in the simulation is avoided by introducing a source merging procedure. The (time-dependent) radiative transfer equation is solved by tracing individual photon packets in an explicitly photon-conserving manner directly on the unstructured grid traced out by the set of SPH particles. To accomplish directed transport of radiation despite the irregular spatial distribution of the SPH particles, photons are guided inside cones. We present and test a parallel numerical implementation of TRAPHIC in the SPH code GADGET-2, specified for the transport of mono-chromatic hydrogen-ionizing radiation. The results of the tests are in excellent agreement with both analytic solutions and results obtained with other state-of-the-art radiative transfer codes.Comment: 31 pages, 20 figures. Accepted for publication in MNRAS. Revised version includes many clarifications and a new time-dependent radiative transfer calculation (fig. 19

Laser-driven micro-explosive bonding of aluminium films to copper and silicon

Laser explosive microfabrication was used to bond micrometre-thick aluminium films to both copper and silicon substrates. Bonding was observed in both systems for laser intensities greater than about 1 × 10 9 W cm −2 and resulted in contiguous, uniform films when performed in a rough vacuum of 25 to 70 millitorr. At intensities greater than 9 × 109 W cm-2 the transferred films were generally black in colour due to oxidation in the aluminium-on-copper shots and due to substrate vaporization in the aluminium-on-silicon shots. SEM examination of the bond interfaces indicated mixing of film and substrate through wave formation and possibly through liquid-phase mixing due to thermal conduction of the laser pulse. Tape adhesion testing of the laser-bonded films showed a significant increase in adhesion over vapour-deposited films in both Al-Cu and Al-Si. Vapour-deposited films were easily removed in their entirety by a single tape pull while metallic portions of the laser-bonded films resisted removal by the tape in all but two tests. The enhanced adhesion evident in the laser-bonded films was a result of intermixing observed at the film-substrate interface.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44689/1/10853_2005_Article_BF01115786.pd

High pressure studies of palladium and platinum thioether macrocyclic dihalide complexes

The mononuclear macrocyclic Pd(II) complex cis-[PdCl2([9 aneS3)] ([9]aneS3 = 1,4,7-trithiacyclononane) converts at 44 kbar into an intensely coloured chain polymer exhibiting distorted octahedral co-ordination at the metal centre and an unprecedented [1233] conformation for the thioether ligand. The evolution of an intramolecular axial sulphur metal interaction and an intermolecular equatorial sulfur-metal interaction is central to these changes. High pressure crystallographic experiments have also been undertaken on the related complexes [PtCl2([9]aneS3)], [PdBr2([9]aneS3)],[PtBr2([9]aneS3)], [PdI2([9]aneS3)] and [PtI2([9]aneS3)] in order to establish the effects of changing the halide ligands and the metal centre on the behaviour of these complexes under pressure. While all complexes undergo contraction of the various interaction distances with increasing pressure, only[PdCl2([9]aneS3)] undergoes a phase change. Pressure-induced I…I interactions were observed for [PdI2([9]aneS3)] and [PtI2([9]aneS3)] at 19 kbar but the corresponding Br…Br interactions in [PdBr2([9]aneS3)] and [PtBr2([9]aneS3)] only become significant at much higher pressure (58 kbar. Accompanying DFT calculations have yielded interaction energies and bond orders for the sulphur metal interactions

Small Big Data: Using multiple data-sets to explore unfolding social and economic change

Bold approaches to data collection and large-scale quantitative advances have long been a preoccupation for social science researchers. In this commentary we further debate over the use of large-scale survey data and official statistics with ‘Big Data’ methodologists, and emphasise the ability of these resources to incorporate the essential social and cultural heredity that is intrinsic to the human sciences. In doing so, we introduce a series of new data-sets that integrate approximately 30 years of survey data on victimisation, fear of crime and disorder and social attitudes with indicators of socio-economic conditions and policy outcomes in Britain. The data-sets that we outline below do not conform to typical conceptions of ‘Big Data’. But, we would contend, they are ‘big’ in terms of the volume, variety and complexity of data which has been collated (and to which additional data can be linked) and ‘big’ also in that they allow us to explore key questions pertaining to how social and economic policy change at the national level alters the attitudes and experiences of citizens. Importantly, they are also ‘small’ in the sense that the task of rendering the data usable, linking it and decoding it, required both manual processing and tacit knowledge of the context of the data and intentions of its creators

Outside-in Shrinking of the Star-forming Disk of Dwarf Irregular Galaxies

We have studied multi-band surface brightness profiles of a representative sample of 34 nearby dwarf irregular galaxies (dIrrs). Our data include GALEX FUV/NUV, UBV, H\alpha, and Spitzer 3.6 \mum images. These galaxies constitute the majority of the LITTLE THINGS survey. By modeling the azimuthal averages of the spectral energy distributions with a complete library of star formation (SF) histories, we derived the stellar mass surface density distributions and the SF rate averaged over three different timescales: the recent 0.1 Gyr, 1 Gyr and a Hubble time. We find that, for \sim 80% (27 galaxies) of our sample galaxies, radial profiles (at least in the outer part) at shorter wavelengths have shorter disk scale lengths than those at longer wavelengths. This indicates that the star-forming disk has been shrinking. In addition, the radial distributions of the stellar mass surface density are well described as piece-wise exponential profiles, and \sim 80% of the galaxies have steeper mass profiles in the outer disk than in the inner region. The steep radial decline of SF rate in the outer parts compared to that in the inner disks gives a natural explanation for the down-bending stellar mass surface density profiles. Within the inner disks, our sample galaxies on average have constant ratios of recent SF rate to stellar mass with radius. Nevertheless, \sim 35% (12 galaxies, among which 7 have baryonic mass < 10^8 M\odot) of the sample exhibit negative slopes across the observed disk, which is in contrast with the "inside-out" disk growth scenario suggested for luminous spiral galaxies. The tendency of SF to become concentrated toward the inner disks in low mass dIrrs is interpreted as a result of their susceptibility to environmental effects and regulation through stellar feedback.Comment: 40 pages. The Astronomical Journal, in pres

Xenopus staufen2 is required for anterior endodermal organ formation

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in genesis 50 (2012): 251-259, doi:10.1002/dvg.22000.Defining the regulatory molecular networks involved in patterning the developing anterior endoderm is essential to understanding how the pancreas, liver, stomach and duodenum are discretely specified from each other. In this study, we analyzed the expression and function of the double-stranded RNA-binding protein Staufen2 in Xenopus laevis endoderm. We found that staufen2 was broadly expressed within the developing endoderm beginning at gastrulation becoming localized to the anterior endoderm at later stages. Through morpholino-mediated knockdown, we demonstrate that Staufen2 function is required for proper formation of the stomach, liver and pancreas. We define that its function is required during gastrulation for proper patterning of the dorsal-ventral axis and that it acts to regulate expression of BMP signaling components.This work was supported by grants from the National Institutes of Health (DK077197) to M.E.H. and from the Canadian Institute of Health Research (Frederick Banting and Charles Best Canada Graduate Scholarships - Doctoral Awards) to C.K.B

Designing for human–agent collectives: display considerations

The adoption of unmanned systems is growing at a steady rate, with the promise of improved task effectiveness and decreased costs associated with an increasing multitude of operations. The added flexibility that could potentially enable a single operator to control multiple unmanned platforms is thus viewed as a potential game-changer in terms of both cost and effectiveness. The use of advanced technologies that facilitate the control of multiple systems must lie within control frameworks that allow the delegation of authority between the human and the machine(s). Agent-based systems have been used across different domains in order to offer support to human operators, either as a form of decision support offered to the human or to directly carry out behaviours that lead to the achievement of a defined goal. This paper discusses the need for adopting a human–agent interaction paradigm in order to facilitate an effective human–agent partnership. An example of this is discussed, in which a single human operator may supervise and control multiple unmanned platforms within an emergency response scenario

Climatic signals in growth and its relation to ENSO events of two Prosopis species following a latitudinal gradient in South America

Semiarid environments throughout the world have lost a major part of their woody vegetation and biodiversity due to the effects of wood cutting, cattle grazing and subsistence agriculture. The resulting state is typically used for cattle production, but the productivity of these systems is often very low, and erosion of the unprotected soil is a common problem. Such dry-land degradation is of great international concern, not only because the resulting state is hardly productive but also because it paves the way to desertification. The natural distribution of the genus Prosopis includes arid and semiarid zones of the Americas, Africa and Asia, but the majority of the Prosopis species are, however, native to the Americas. In order to assess a likely gradient in the response of tree species to precipitation, temperature and their connection to El Niño southern oscillation (ENSO) events, two Prosopis species were chosen along a latitudinal gradient in Latin America, from northern Peru to central Chile: Prosopis pallida from a semi-arid land in northern and southern Peru and P. chilensis from a semiarid land in central Chile. Growth rings of each species were crossdated at each sampling site using classical dendrochronological techniques. Chronologies were related with instrumental climatic records in each site, as well as with SOI and N34 series. Cross-correlation, spectral and wavelet analysis techniques were used to assess the relation of growth with precipitation and temperature. Despite the long distance among sites, the two Prosopis species presented similar responses. Thus, the two species' growth is positively correlated to precipitation, while with temperature it is not. In northern Peru, precipitation and growth of P. pallida present a similar cyclic pattern, with a period of around 3 years. On the other hand, P. pallida in southern Peru, and P. chilensis also present this cyclic pattern, but also another one with lower frequency, coinciding with the pattern of precipitation. Both cycles are within the range of the ENSO band

South End Mound complex

46 p. : ill., maps ; 26 cm.Includes bibliographical references (p. 44-46)."This volume presents results of archaeological excavations of two prehistoric burial mounds on St. Catherines Island, Georgia. South End Mound I is an Irene period mortuary site, initially excavated by C.B. Moore during the winter of 1896-1897. Although Moore adequately described his investigations in a subsequent publication, he retained only six complete ceramic vessels for later analysis. These vessels have been reexamined and are discussed here. None of the skeletal materials excavated by Moore, to our knowledge, was saved for later analysis. Field crews from the American Museum of Natural History recently reexcavated parts of this site, finding evidence that at least some of the primary human burials previously exposed by Moore remain intact beneath the backdirt of South End Mound I. Further investigation might be fruitful. South End Mound II, a previously unexplored mortuary site, was discovered not far from Moore's excavations. This St. Catherines/Savannah period burial mound, extensively excavated by the American Museum of Natural History, had a central pit containing two cremations and a mass grave containing at least 15 individuals. Grave goods included a perforated copper sheet, worked galena, a river otter mandible, and a polished stone pendant. Prehistoric copper has rarely been reported from archaeological contexts from this area and, to our knowledge, this is the first occurrence of galena in coastal Georgia. Mound construction methods resemble those employed at Johns and Marys mounds, two roughly contemporary mortuary sites on St. Catherines Island"--P. 4