1,809 research outputs found

    Decision-support system for risk management of produced water in the offshore petroleum industry

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    A decision-support system for produced water management (DISSPROWM) in offshore operations is being developed. The system determines the risk and hazards to human and marine species from non-carcinogenic and carcinogenic pollutants, including radionuclides present in produced water. The DISSPROWM also evaluates the best available treatment technology for treating the produced water whose properties are in the database. The system consists of a Windows-based Graphical User Interface (GUI) developed with Microsoft Visual Basic, which integrates a SQL Server database, a risk assessment model and a dilution model for produced water contaminants. The database contains most produced water pollutants and their important properties that are required in dispersion and risk assessment modelling. The database also contains current produced water regulations and information on some of the selected existing treatment technologies with typical cost data required in the decision-support system

    Effects of geometry variations on the performance of podded propulsors

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    This paper presents results and analyses of an experimental study into the effects of geometric parameters on the propulsive characteristics of puller and pusher podded propulsors in straight course open water conditions. Five geometric parameters were chosen for the current study and a design of experiment technique was used to design a series of 16 pods that combined the parameters. Tests on the 16 different pod-strut-propeller combinations in puller and pusher configurations were completed using a custom designed podded propeller test rig. The dynamometry consisted of a six-component global dynamometer and a three-component pod dynamometer. The test rig was used to measure the thrust and torque of the propellers, and forces and moments on the whole unit in the three orthogonal directions. The design of experiment analysis technique was then used to identify the most significant geometric parameters and interaction of parameters that affect propeller thrust, torque and efficiency as well as unit thrust and efficiency in both the puller and pusher configurations. An uncertainty analysis of the measurements is also presented

    Experiments with Podded Propulsors in Static Azimuthing Conditions

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    The paper presents a comprehensive experimental study of the variations of propulsive characteristics of puller and pusher podded propulsors in static azimuthing open water conditions. A custom designed six-component global dynamometer and a three-component pod dynamometer were used to measure the propulsive performance of a podded unit in pusher and puller configurations in a towing tank. The unit was tested to measure the forces on the whole unit in the three co-ordinate directions as well as thrust and torque of the propeller for a range of advance coefficients combined with the range of static azimuthing angles from +30° to –30° with 5° and 10° increments. The variations in propulsive performance of the unit with change of azimuthing angle and advance speed in the two configurations were examined. The results of the measurements are presented as changes of forces and moments of the propulsor unit with advance coefficients and azimuthing angles. The results illustrate that the axial and side forces and the steering moment are complex functions of the azimuthing angles both for puller and pusher propulsors

    Negative Quasi-Probability as a Resource for Quantum Computation

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    A central problem in quantum information is to determine the minimal physical resources that are required for quantum computational speedup and, in particular, for fault-tolerant quantum computation. We establish a remarkable connection between the potential for quantum speed-up and the onset of negative values in a distinguished quasi-probability representation, a discrete analog of the Wigner function for quantum systems of odd dimension. This connection allows us to resolve an open question on the existence of bound states for magic-state distillation: we prove that there exist mixed states outside the convex hull of stabilizer states that cannot be distilled to non-stabilizer target states using stabilizer operations. We also provide an efficient simulation protocol for Clifford circuits that extends to a large class of mixed states, including bound universal states.Comment: 15 pages v4: This is a major revision. In particular, we have added a new section detailing an explicit extension of the Gottesman-Knill simulation protocol to deal with positively represented states and measurement (even when these are non-stabilizer). This paper also includes significant elaboration on the two main results of the previous versio

    Studying stellar binary systems with the Laser Interferometer Space Antenna using Delayed Rejection Markov chain Monte Carlo methods

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    Bayesian analysis of LISA data sets based on Markov chain Monte Carlo methods has been shown to be a challenging problem, in part due to the complicated structure of the likelihood function consisting of several isolated local maxima that dramatically reduces the efficiency of the sampling techniques. Here we introduce a new fully Markovian algorithm, a Delayed Rejection Metropolis-Hastings Markov chain Monte Carlo method, to efficiently explore these kind of structures and we demonstrate its performance on selected LISA data sets containing a known number of stellar-mass binary signals embedded in Gaussian stationary noise.Comment: 12 pages, 4 figures, accepted in CQG (GWDAW-13 proceedings

    Fast rise time, long pulse width, kilohertz repetition rate Q-switch driver

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    The following article appeared in Review of Scientific Instruments, 2007; 78 (7):073108-1-073108-2 and may be found at http://link.aip.org/link/?RSINAK/78/073108/1 .We describe a versatile Pockels cell Q-switch driver that can generate high voltage electrical pulses having both fast rise times and long duration, with a repetition rate in excess of 1 kHz. The circuit is simple and easily adaptable to most types of Q-switched lasers and regenerative amplifiers.Thomas P. Rutten, Neville Wild, and Peter J. Veitchhttp://link.aip.org/link/?RSINAK/78/073108/

    MF59-adjuvanted H1N1v vaccine

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    Summary Background:  When H1N1v vaccines become widely available, most elderly subjects will have already received their seasonal influenza vaccination. Adults seeking H1N1v vaccination may be offered seasonal vaccine as well. We investigated prior seasonal vaccination in adult and elderly subjects, and concomitant vaccination with seasonal vaccine in adults, on the tolerability and immunogenicity of the Novartis MF59-adjuvanted H1N1v vaccine, Focetria®. Methods:  A total of 264 adult (four groups) and 154 elderly (three groups) subjects were enrolled. The licensure study cohorts for plain (Agrippal®) and MF59-adjuvanted (Fluad®) 2009–2010 seasonal vaccines were invited to receive Focetria 3 months later, with seasonal vaccine–naive controls, and adults who received Focteria and seasonal vaccine concomitantly. Immunogenicity of all vaccines was assessed by haemagglutination inhibition on Days 1 and 22, safety and reactogenicity were monitored using patient diaries. Results:  All adult and elderly groups met all the European CHMP licensing criteria for H1N1v, as did adults receiving concomitant seasonal vaccine for the three seasonal strains. Vaccines were generally well tolerated, causing no SAEs, and profiles typical of MF59-adjuvanted vaccines. Reactions were mainly mild or moderate and transient, and unaffected by prior or concomitant seasonal vaccination except for elderly subjects previously given MF59-adjuvanted seasonal vaccine, whose reaction rates to Focetria were about half those seen in groups receiving their first MF59 vaccine. Conclusion:  One dose of MF59-adjuvanted H1N1v vaccine met the licensure criteria for adult and elderly subjects 3 months after seasonal vaccination, or concomitantly with seasonal vaccine in adults, without impacting the tolerability or immunogenicity of either vaccine, thus facilitating mass influenza immunisation campaigns
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