46 research outputs found

    The effects of higher oxygenates on methanol synthesis

    Get PDF
    In the current investigation the effects of higher oxygenate species on the methanol synthesis performance of various methanol synthesis catalysts were examined. Experiments were performed whereby a selected higher oxygenate (such as a carboxylic acid) was co-fed into a methanol synthesis system at low concentrations, and the results monitored by on-line GC analysis. Bulk changes in the morphology of the catalysts post reaction were investigated using XRD. Temperature programmed oxidations (TPO’s) were also performed on the catalysts post reaction to determine if carbon deposition occurred during reaction. Catalysts investigated include Rh/SiO2, Ir/SiO2, Pd/SiO2, Pd/Ca/SiO2 and an industrial methanol synthesis catalyst of a Cu/ZnO/Al2O3 formulation. The effect of the feed gas on the behaviour of the higher oxygenates were also investigated by varying the feed gas composition

    The Auld Enemy? Exploring the England vs. Scotland rivalry from the perspective of soccer fans

    Get PDF
    A longstanding and persistent rivalry is said to exist between England and Scotland in the context of international soccer. In this essay we seek to test common media representations emphasising division against the opinions of English and Scottish soccer fans themselves. The complexity of English views towards Scottish people both inside and outside of soccer is explored using examples from an online participant observation study with English fans. Moreover, the extent to which anti-English sentiment constitutes an element of Scottish national identity in soccer and society more broadly is also explored using examples from semi-structured interviews with Scottish fans on the topic of the rivalry between the two nations. We argue that via representations in the media soccer has both provided the context for reinforcing broader divisions between these neighbouring nations as well as creating specific memories in the minds of soccer fans that enhance divisive feelings amongst some English and Scottish fans. However, we also note the extent to which the stereotype of division is perpetuated by the media and how this is sometimes at odds with the views of both Scottish and English fans alike. We conclude that so long as the media perpetuate division between the two nations in a simplistic manner the reality of the complex and evolving relationship between Scottish and English fans will remain unclear and misunderstood

    High-Energy Cosmic Rays from Gamma-Ray Bursts

    Full text link
    A model is proposed for the origin of cosmic rays (CRs) from ~10^14 eV to the highest energies, >10^20 eV. Gamma-Ray Bursts (GRBs) are assumed to inject CR protons and ions into the interstellar medium of star-forming galaxies--including the Milky Way--with a power law spectrum extending to a maximum energy ~10^20 eV. The CR spectrum near the knee is fit with CRs trapped in the Galactic halo that were accelerated and injected by an earlier Galactic GRB. These CRs diffuse in the disk and halo of the Galaxy due to gyroresonant pitch-angle scattering with MHD turbulence in the Galaxy's magnetic field. The preliminary (2001) KASCADE data through the knee of the CR spectrum are fit by a model with energy-dependent propagation of CR ions from a single Galactic GRB. Ultra-high energy CRs (UHECRs), with energies above the ankle are assumed to propagate rectilinearly with their spectrum modified by photo-pion, photo-pair, and expansion losses. We fit the measured UHECR spectrum assuming comoving luminosity densities of GRB sources consitent with possible star formation rate histories of the universe. For power-law CR proton injection p>2 this model implies that the nonthermal content in the GRB blast waves is hadronically dominated by a factor ~60-200. Calculations show that 100 TeV-100 PeV neutrinos could be detected several times per year from all GRBs in kilometer-scale neutrino detectors such as IceCube, for GRB blast-wave Doppler factors <~200. GLAST measurements of gamma-ray components and cutoffs will constrain the product of nonthermal baryon loading and radiative efficiency, limit the Doppler factor, and test this senario.Comment: 43 pages, 21 figures, to appear in Astropart. Phy

    An ALMA survey of the SCUBA-2 CLS UDS field: physical properties of 707 sub-millimetre galaxies

    Get PDF
    We analyse the physical properties of a large, homogeneously selected sample of ALMA-located sub-millimetre galaxies (SMGs). This survey, AS2UDS, identified 707 SMGs across the ∼1 deg2 field, including ∼17 per cent, which are undetected at K ≳ 25.7 mag. We interpret their ultraviolet-to-radio data using magphys and determine a median redshift of z = 2.61 +- 0.08 (1σ range of z = 1.8-3.4) with just ∼6 per cent at z > 4. Our survey provides a sample of massive dusty galaxies at z ≳ 1, with median dust and stellar masses of Md = (6.8 +- 0.3) x 108 M⊙ (thus, gas masses of ∼1011 M⊙) and M* = (1.26 +- 0.05) x 1011 M⊙. We find no evolution in dust temperature at a constant far-infrared luminosity across z ∼ 1.5-4. The gas mass function of our sample increases to z ∼ 2-3 and then declines at z > 3. The space density and masses of SMGs suggest that almost all galaxies with M* ≳ 3 x 1011 M⊙ have passed through an SMG-like phase. The redshift distribution is well fit by a model combining evolution of the gas fraction in haloes with the growth of halo mass past a critical threshold of Mh ∼ 6 x 1012 M⊙, thus SMGs may represent the highly efficient collapse of gas-rich massive haloes. We show that SMGs are broadly consistent with simple homologous systems in the far-infrared, consistent with a centrally illuminated starburst. Our study provides strong support for an evolutionary link between the active, gas-rich SMG population at z > 1 and the formation of massive, bulge-dominated galaxies across the history of the Universe.The Durham co-authors acknowledge support from STFC (ST/P000541/1). The authors thank John Helly and Lydia Heck for help with HPC. The ALMA data used in this paper were obtained under programs ADS/JAO.ALMA#2012.1.00090.S, #2015.1.01528.S, and #2016.1.00434.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This work used the DiRAC@Durham facility managed by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). The equipment was funded by BEIS capital funding via STFC capital grants ST/K00042X/1, ST/P002293/1, ST/R002371/1, and ST/S002502/1, Durham University and STFC operations grant ST/R000832/1. DiRAC is part of the National e-Infrastructure. We extend our gratitude to the staff at UKIRT for their tireless efforts in ensuring the success of the UKIDSS UDS project. EdC gratefully acknowledges the Australian Research Council as the recipient of a Future Fellowship (project FT150100079). JLW acknowledges support from an STFC Ernest Rutherford Fellowship (ST/P004784/1 and ST/P004784/2

    An ALMA Survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS Field: Number Counts of Submillimeter Galaxies

    Get PDF
    We report the first results of AS2UDS, an 870 μm continuum survey with the Atacama Large Millimeter/Submillimeter Array (ALMA) of a total area of ~50 arcmin2 comprising a complete sample of 716 submillimeter sources drawn from the SCUBA-2 Cosmology Legacy Survey (S2CLS) map of the UKIDSS/UDS field. The S2CLS parent sample covers a 0.96 degree2 field at σ 850 = 0.90 ± 0.05 mJy beam−1. Our deep, high-resolution ALMA observations with σ 870 ~ 0.25 mJy and a 0farcs15–0farcs30 FWHM synthesized beam, provide precise locations for 695 submillimeter galaxies (SMGs) responsible for the submillimeter emission corresponding to 606 sources in the low-resolution, single-dish map. We measure the number counts of SMGs brighter than S 870 ≥ 4 mJy, free from the effects of blending and show that the normalization of the counts falls by 28% ± 2% in comparison with the SCUBA-2 published counts, but that the shape remains unchanged. We determine that 4414+16{44}_{-14}^{+16}% of the brighter single-dish sources with S 850 ≥ 9 mJy consist of a blend of two or more ALMA-detectable SMGs brighter than S 870 ~ 1 mJy (corresponding to a galaxy with a total-infrared luminosity of L IR gsim 1012 L ⊙), in comparison with 28% ± 2% for the single-dish sources at S 850 ≥ 5 mJy. Using the 46 single-dish submillimeter sources that contain two or more ALMA-detected SMGs with photometric redshifts, we show that there is a significant statistical excess of pairs of SMGs with similar redshifts (<1% probability of occurring by chance), suggesting that at least 30% of these blends arise from physically associated pairs of SMGs

    An ALMA survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS field: source catalogue and properties

    Get PDF
    We present the catalogue and basic properties of sources in AS2UDS, an 870-μm continuum survey with the Atacama Large Millimetre/sub-millimetre Array (ALMA) of 716 single-dish sub-millimetre sources detected in the UKIDSS/UDS field by the SCUBA-2 Cosmology Legacy Survey. In our sensitive ALMA follow-up observations, we detect 708 sub-millimetre galaxies (SMGs) at >4.3σ significance across the ∼1◦-diameter field. We combine our precise ALMA positions with the extensive multiwavelength coverage in the UDS field which yields spectral energy distributions for our SMGs and a median redshift of zphot = 2.61 ± 0.09. This large sample reveals a statistically significant trend of increasing sub-millimetre flux with redshift suggestive of galaxy downsizing. 101 ALMA maps do not show a > 4.3σ SMG, but we demonstrate from stacking Herschel SPIRE observations at these positions, that the vast majority of these blank maps correspond to real single-dish sub-millimetre sources. We further show that these blank maps contain an excess of galaxies at zphot = 1.5–4 compared to random fields, similar to the redshift range of the ALMA-detected SMGs. In addition, we combine X-ray and mid-infrared active galaxy nuclei activity (AGN) indicators to yield a likely range for the AGN fraction of 8–28 per cent in our sample. Finally, we compare the redshifts of this population of high-redshift, strongly star-forming galaxies with the inferred formation redshifts of massive, passive galaxies being found out to z ∼ 2, finding reasonable agreement – in support of an evolutionary connection between these two classes of massive galaxySMS acknowledges the support of STFC studentship (ST/N50404X/1). AMS and IS acknowledge financial support from an STFC grant (ST/P000541/1). IS, EAC and BG also acknowledge support from the ERC Advanced Investigator program DUSTYGAL (321334). JLW acknowledges support from an STFC Ernest Rutherford Fellowship (ST/P004784/1 and ST/P004784/2). JEG acknowledges support from a Royal Society University Research Fellowship. MJM acknowledges the support of the National Science Centre, Poland through the POLONEZ grant 2015/19/P/ST9/04010; this project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 665778. T. Miyaji and the development of CSTACK is supported by UNAM-DGAPA IN104216,IN111319 and CONACyT 252531

    Glasgow 2014, the media and Scottish politics – the (post)imperial symbolism of the Commonwealth Games

    Get PDF
    This article critically examines print media discourses regarding the 2014 Glasgow Commonwealth Games. The forthcoming analysis considers the political symbolism of the Commonwealth Games with regards to the interlinkages between the British Empire, sport and the global political status of the UK, with specific consideration given to the UK’s declining global power as well as the interconnections between the 2014 Games and the Scottish independence referendum. Hechter’s (1975) ‘internal colonialism’ thesis, which portrays Scotland’s marginalised status within the UK, is drawn upon to critically explore the political symbolism of sport for Scottish nationalism, before discussion focuses upon the extent to which the modern Commonwealth is symptomatic of the UK’s declining status as a global power. Finally, the existence of these narrative tropes in print media coverage of the Commonwealth Games is examined, allowing for critical reflections on the continuing interconnections between the media, sport, nationalism and post-imperial global politics

    Sport for Yes? The role of sporting issues in pro-independence political discourse during the Scottish independence referendum campaign

    Get PDF
    This article critically considers the extent to which sporting issues were harnessed by pro-independence political campaigners during the Scottish independence referendum campaign. Developments such as the inclusion of sport within the Scottish Government’s White Paper on Scottish independence, the establishment of the ‘Working Group on Scottish Sport’ and the establishment of the ‘Sport for Yes’ campaign group demonstrate the harnessing of sporting issues as an additional, if somewhat peripheral, debate point in the referendum campaigns (Lafferty 2014, Scottish Government 2013, Working Group on Scottish Sport and Scottish Government 2013, 2014). The latter of these developments, the establishment of the ‘Sport for Yes’ campaign group, is of particular interest, offering evidence of the explicit political mobilisation of past and present athletes in support of the ‘Yes Scotland’ pro-independence campaign. The use of sport within pro-independence political discourse is therefore scrutinised, drawing upon the principles of critical discourse analysis to explore the ideological assumptions underpinning the discursive representation of sport in relation to Scottish independence
    corecore