619 research outputs found
Putting the Brit into Eurohorror: Exclusions and Exchanges in the History of European Horror Cinema
British horror cinema is often excluded from critical work dealing with European horror cinema or, as it is frequently referred to, ‘Eurohorror’. This article argues that such exclusion is unwarranted. From the 1950s onwards there have been many exchanges between British and continental European-based horror production. These have involved not just international co-production deals but also creative personnel moving from country to country. In addition, British horror films have exerted influence on European horror cinema and vice versa. At the same time, the exclusion of British horror from the ‘Eurohorror’ category reveals limitations in that category, particularly its idealisation of continental European horror production
In-shock Cooling in Numerical Simulations
We model a one-dimensional shock-tube using smoothed particle hydrodynamics
and investigate the consequences of having finite shock-width in numerical
simulations. We investigate the cooling of gas during passage through the shock
for different cooling regimes. For a shock temperature of 10^5K, the maximum
temperature of the gas is much reduced and the cooling time was reduced by a
factor of 2. At lower temperatures, we are especially interested in the
production of molecular Hydrogen and so we follow the ionization level and H_2
abundance across the shock. This regime is particularly relevent to simulations
of primordial galaxy formation for halos in which the virial temperature of the
galaxy is sufficiently high to partially re-ionize the gas. The effect of
in-shock cooling is substantial: the maximum temperature the gas reaches
compared to the theoretical temperature was found to vary between 0.15 and 0.81
for the simulations performed. The downstream ionization level is reduced from
the theoretical level by a factor of between 2.4 and 12.5, and the resulting
H_2 abundance was found to be reduced to a fraction of 0.45 to 0.74 of its
theoretical value. At temperatures above 10^5K, radiative shocks are unstable
and will oscillate. We reproduce these oscillations and find good agreement
with the previous work of Chevalier and Imamura (1982), and Imamura, Wolff and
Durisen (1984). The effect of in-shock cooling in such shocks is difficult to
quantify, but is undoubtedly present.Comment: 8 pages, LaTeX, 7 figure
Discovery, development, and commercialization of gold catalysts for acetylene hydrochlorination
Vinyl chloride monomer (VCM) is a major chemical intermediate for the manufacture of polyvinyl chloride (PVC), which is the third most important polymer in use today. Hydrochlorination of acetylene is a major route for the production of vinyl chloride, since production of the monomer is based in regions of the world where coal is abundant. Until now, mercuric chloride supported on carbon is used as the catalyst in the commercial process, and this exhibits severe problems associated with catalyst lifetime and mercury loss. It has been known for over 30 years that gold is a superior catalyst, but it is only now that it is being commercialized. In this Perspective we discuss the use and disadvantages of the mercury catalyst and the advent of the gold catalysts for this important reaction. The nature of the active site and the possible reaction mechanism are discussed. Recent advances in the design and preparation of active gold catalysts containing ultralow levels of gold are described. In the final part, a view to the future of this chemistry will be discussed as well as the possible avenues for the commercial potential of gold catalysis
American vampires in Britain: Richard Matheson's 'I am legend' and Hammer's 'The night creatures'
Pd/ZnO catalysts for direct CO2 hydrogenation to methanol
The direct hydrogenation of CO2 into methanol is crucial for providing a means of CO2 fixation and a way to store cleanly produced hydrogen in a more energy-dense and transportable form. Here we have prepared two series of Pd/ZnO catalysts, both by immobilisation of PVA-protected Pd colloids and by Pd impregnation of PdCl2 to investigate structure activity relationships for direct CO2 hydrogenation. Very different performances were found for the different preparation methods, and the Pd loading and pre-reduction of the catalysts were shown to be important factors for optimising methanol yield. The crucial factor for high methanol yield is the formation of a Pd–Zn alloy, either during the reaction itself, or better by high temperature pre-reduction. The formation of the alloy greatly reduces CO production by the reverse water gas shift reaction. The catalysts prepared by sol-immobilisation were relatively stable to thermal treatment. In contrast, the impregnated catalysts were much less thermally stable, due to the presence of remnant chloride on the surface of the catalyst, which was absent for the case of sol immobilisation preparation. The results illustrate the importance of controlling the PdZn particle size and its surface structure for the catalysts to achieve high methanol selectivity (60%, the rest being CO) and conversion (11%) at 250 °C and 20 bar. Selectivity for sol-immobilised catalysts decreases from 60% at 3 nm average diameter, to 20% at 7 nm
New reactivity patterns of copper(I) and other transition metal NHC complexes: application to ATRC and related reactions
Fire and Forget! One-Shot Synthesis and Characterization of Block-Like Statistical Terpolymers via Living Anionic Polymerization
Gold as a catalyst for the ring opening of 2,5-Dimethylfuran
The epoxidation of 2,5-dimethyl furan leads to the production of hex-3-ene-2,5-dione via a ring opening rearrangement reaction. A second epoxidation reaction could then enable a further ring closing rearrangement to form 4-hydroxy-2,5-dimethyl-3-furanone (furaneol). In this paper we report the use of gold and gold palladium supported on graphite and titania as catalysts for the ring opening reaction of 2,5-dimethyl furan. We show that by tuning the reaction conditions high selectivity towards hex-3-ene-2,5-dione can be achieved using green chemical methods and mild reaction conditions
Selective hydrogenation of levulinic acid using Ru/C catalysts prepared by sol-immobilsation
A 1% Ru/C catalyst prepared by the sol immobilization method showed a high yield of γ-valerolactone from levulinic acid. We performed an optimization of the catalyst by varying the preparation variables involved in the sol immobilization method and detremined that the ratio of PVA, NaBH4 to Ru and heat treatment conditions play a crucial role in the synthesis of active and selective catalysts. By varying these parameters we have identified the optimum conditions for catalyst preparation by providing well dispersed nanoparticles of RuOx on the carbon support that are reducible under low reaction temperature and in turn gave an enhanced catalytic activity. In contrast to a catalyst prepared without using a PVA stabiliser, the use of a small amount PVA (PVA/Ru = 0.1) provided active nanoparticles, by controlling the steric size of the Ru nanoparticles. An optimum amount of NaBH4 was required in order to provide the reducible Ru species on the surface of catalyst and further increase in NaBH4 was found to cause a decline in activity that was related to the kinetics of nanoparticle formation during catalyst preparation. A variation of heat treatment temperature showed a corresponding decrease in catalytic activity linked with the sintering and an increase in particle size
Preparation of aromatic compound e.g. 1-chloronaphthalene involves exposing pre-formed benzenoid to an energy source in the presence of a catalyst system
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