622 research outputs found
Turbulence modelling of multiphase flow in high-pressure trickle-bed reactors
http://www.sciencedirect.com/science/article/B6TFK-4VB01VS-7/2/7dcce0ca6c1ed57a847371407b038f1
Trickle-bed CFD studies in the catalytic wet oxidation of phenolic acids
An Euler-Euler computational fluid model was developed successfully for the hydrodynamic prediction of a trickle-bed reactor (TBR) designed for advanced wastewater treatment facilities. Catalytic wet air oxidation of phenolic acids was simulated in a TBR by means of computational fluid dynamic (CFD) in the temperature range and pressures . The hydrodynamic model validation was accomplished through the comparison of simulated pressure drop and liquid holdup with experimental data from the literature. In a broad range of gas and liquid flows studied (G=0.10-0.70 and ) at different operation conditions, CFD demonstrated the considerable effect of operating pressure in pressure drop, whereas a minor influence was detected for the liquid holdup. CFD runs were then performed for the catalytic wet air oxidation of aqueous phenolic acids solution. The reactor behaviour was analysed by means of total organic carbon profiles which reflected the influence of temperature, pressure, gas-liquid flows and initial pollutant concentration.http://www.sciencedirect.com/science/article/B6TFK-4PPMXS0-1/1/2dabed7df5e98dfd85f3fef6ef64782
Quantum and Classical divide: the gravitational case
We study the transition between quantum and classical behavior of particles
in a gravitational quantum well. We analyze how an increase in the particles
mass turns the energy spectrum into a continuous one, from an experimental
point of view. We also discuss the way these effects could be tested by
conducting experiments with atoms and fullerene-type molecules.Comment: Revtex4, 5 pages, 2 figures; version to appear in Physics Letters
Automatically Generating and Updating User Interface Components in Process-Aware Information Systems
The increasing adoption of process-aware information systems (PAISs) has resulted in a large number of implemented business processes. To react on changing needs, companies need to be able to quickly adapt these process implementations. Current PAISs only provide mechanisms to evolve the schema of a process, but do not support the automated creation and adaptation of user interfaces (UIs).
The latter may have a complex logic and comprise conditional elements or database queries. Creating and evolving UIs manually is a tedious and error-prone task. This paper introduces a set of patterns for transforming fragments of a business process, whose activities are performed by the same user role, to UIs of the PAIS. In particular, UI logic can be expressed using the same notation as for process modeling. Furthermore, a transformation method is introduced, which applies these patterns to automatically derive UIs by establishing a bidirectional mapping between process model and UI. This mapping allows propagating UI changes to the process model and vice versa. Overall, our approach enables process designers to rapidly develop and update complex UIs in PAISs
On the possibility of light string resonances at the LHC and Tevatron from Randall-Sundrum throats
In string realizations of the Randall-Sundrum scenario, the higher-spin Regge
excitations of Standard Model states localized near the IR brane are warped
down to close to the TeV scale. We argue that, as a consequence of the
localization properties of Randall-Sundrum models of flavour, the lightest such
resonance is the spin-3/2 excitation of the right-handed top quark over a
significant region of parameter space. A mild accidental cancellation allows
this resonance to be as light or lighter than the Kaluza-Klein excitations of
the Standard Model states. We consider from a bottom-up effective theory point
of view the production and possible observability of such a spin-3/2 excitation
at the LHC and Tevatron. Current limits are weaker than might be expected
because of the excess of WWjj events at the Tevatron reported by CDF for an
invariant mass of 400-500 GeV.Comment: 17 pages, 6 figures Version published in JHEP with minor correction
Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths
We review observations of several classes of neutron-star-powered outflows:
pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe
interacting directly with interstellar medium (ISM), and magnetar-powered
outflows. We describe radio, X-ray, and gamma-ray observations of PWNe,
focusing first on integrated spectral-energy distributions (SEDs) and global
spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering
array of morphologies, with jets, trails, and other structures. Several of the
23 so far identified magnetars show evidence for continuous or sporadic
emission of material, sometimes associated with giant flares, and a few
possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published
in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray
Bursts and Blazars: Physics of Extreme Energy Release
Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources
We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples
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