237 research outputs found

    Overview of Actual Methods for Characterization of Ash Depostion

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    Utility operation with frequent fuel switching is a common practice, forced by cheaper coal availability in the international market. Additionally, a substitution of coal by cheaper local secondary fuels, ranging from forest wood to sewage sludge and industrial or domestic residues, is gaining importance. Switching between different fuels, even if these do not differ much from the design coal, enhances operational problems arising from ash deposition. In order to prevent operational problems, through comprehension of the phenomena taking place within the furnace, appropriate sampling and characterization of the deposits are necessary. Methods commonly used for analysis of ash deposits and their characterization are summarized in this paper. The goals of the experimental work at the Institute of Process Engineering and Power Plant Technology (IVD) are then summarized. Finally, work on modeling the slagging and fouling phenomena or their characterization is presented

    Characterization of SU(1,1) coherent states in terms of affine group wavelets

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    The Perelomov coherent states of SU(1,1) are labeled by elements of the quotient of SU(1,1) by the compact subgroup. Taking advantage of the fact that this quotient is isomorphic to the affine group of the real line, we are able to parameterize the coherent states by elements of that group or equivalently by points in the half-plane. Such a formulation permits to find new properties of the SU(1,1) coherent states and to relate them to affine wavelets.Comment: 11 pages, latex, to be published in J. Phys. A : Math. Ge

    TLR1/2 and 5 induce elevated cytokine levels from rheumatoid arthritis monocytes independent of ACPA or RF autoantibody status

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    Objective RA is an autoimmune inflammatory joint disease. Both RF and ACPA are associated with more progressive disease and higher levels of systemic inflammation. Monocyte activation of toll-like receptors (TLRs) by endogenous ligands is a potential source of increased production of systemic cytokines. RA monocytes have elevated TLRs, some of which are associated with the disease activity score using 28 joints (DAS28). The aim of this study was to measure TLR-induced cytokine production from monocytes, stratified by autoantibody status, to assess if their capacity to induce cytokines is related to autoantibody status or DAS28. Methods Peripheral blood monocytes isolated from RA patients and healthy controls were stimulated with TLR1/2, TLR2/6, TLR4, TLR5, TLR7, TLR8 and TLR9 ligands for 18 h before measuring IL-6, TNFα and IL-10. Serum was used to confirm the autoantibody status. Cytokine levels were compared with RF, ACPA and DAS28. Results RA monocytes demonstrated significantly increased IL-6 and TNFα upon TLR1/2 stimulation and IL-6 and IL-10 upon TLR5 activation. TLR7 and TLR9 activation did not induce cytokines and no significant differences were observed between RA and healthy control monocytes upon TLR2/6, TLR4 or TLR8 activation. When stratified by ACPA or RF status there were no correlations between autoantibody status and elevated cytokine levels. However, TLR1/2-induced IL-6 did correlate with DAS28. Conclusions Elevated TLR-induced cytokines in RA monocytes were not related to ACPA or RF status. However, TLR1/2-induced IL-6 was associated with disease activity

    Making SENSE--Sustained Effort Network for treatment of Status Epilepticus as a multicenter prospective registry.

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    BACKGROUND: Evidence regarding the different treatment options of status epilepticus (SE) in adults is scarce. Large randomized trials cover only one treatment at early stage and suggest the superiority of benzodiazepines over placebo, of intravenous lorazepam over intravenous diazepam or over intravenous phenytoin alone, and of intramuscular midazolam over intravenous lorazepam. However, many patients will not be treated successfully with the first treatment step. A large randomized trial covering the treatment of established status (ESETT) has just been funded recently by the NIH and will not start before 2015, with expected results in 2018; a trial on the treatment of refractory status with general anesthetics was terminated early due to insufficient recruitment. Therefore, a prospective multicenter observational registry was set up; this may help in clinical decision-making until results from randomized trials are available. METHODS/DESIGN: SENSE is a prospective, multicenter registry for patients treated for SE. The primary objective is to document patient characteristics, treatment modalities and in-house outcome of consecutive adults admitted for SE treatment in each of the participating centres and to identify predictors of outcome. Pre-treatment, treatment-related and outcome variables are documented systematically. To allow for meaningful multivariate analysis in the patient subgroups with refractory SE, a cohort size of 1000 patients is targeted. DISCUSSION: The results of the study will provide information about risks and benefits of specific treatment steps in different patient groups with SE at different points of time. Thus, it will support clinical decision-making and, furthermore, it will be helpful in the planning of treatment trials. TRIAL REGISTRATION: DRKS00000725

    Staged treatment response in status epilepticus: Lessons from the SENSE registry.

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    Although in epilepsy patients the likelihood of becoming seizure-free decreases substantially with each unsuccessful treatment, to our knowledge this has been poorly investigated in status epilepticus (SE). We aimed to evaluate the proportion of SE cessation and functional outcome after successive treatment steps. We conducted a post hoc analysis of a prospective, observational, multicenter cohort (Sustained Effort Network for treatment of Status Epilepticus [SENSE]), in which 1049 incident adult SE episodes were prospectively recorded at nine European centers. We analyzed 996 SE episodes without coma induction before the third treatment step. Rates of SE cessation, mortality (in ongoing SE or after SE control), and favorable functional outcome (assessed with modified Rankin scale) were evaluated after each step. SE was treated successfully in 838 patients (84.1%), 147 (14.8%) had a fatal outcome (36% of them died while still in SE), and 11 patients were transferred to palliative care while still in SE. Patients were treated with a median of three treatment steps (range 1-13), with 540 (54.2%) receiving more than two steps (refractory SE [RSE]) and 95 (9.5%) more than five steps. SE was controlled after the first two steps in 45%, with an additional 21% treated after the third, and 14% after the fourth step. Likelihood of SE cessation (p < 0.001), survival (p = 0.003), and reaching good functional outcome (p < 0.001) decreased significantly between the first two treatment lines and the third, especially in patients not experiencing generalized convulsive SE, but remained relatively stable afterwards. The significant worsening of SE prognosis after the second step clinically supports the concept of RSE. However, and differing from findings in human epilepsy, RSE remains treatable in about one third of patients, even after several failed treatment steps. Clinical judgment remains essential to determine the aggressiveness and duration of SE treatment, and to avoid premature treatment cessation in patients with SE

    A dimensionally continued Poisson summation formula

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    We generalize the standard Poisson summation formula for lattices so that it operates on the level of theta series, allowing us to introduce noninteger dimension parameters (using the dimensionally continued Fourier transform). When combined with one of the proofs of the Jacobi imaginary transformation of theta functions that does not use the Poisson summation formula, our proof of this generalized Poisson summation formula also provides a new proof of the standard Poisson summation formula for dimensions greater than 2 (with appropriate hypotheses on the function being summed). In general, our methods work to establish the (Voronoi) summation formulae associated with functions satisfying (modular) transformations of the Jacobi imaginary type by means of a density argument (as opposed to the usual Mellin transform approach). In particular, we construct a family of generalized theta series from Jacobi theta functions from which these summation formulae can be obtained. This family contains several families of modular forms, but is significantly more general than any of them. Our result also relaxes several of the hypotheses in the standard statements of these summation formulae. The density result we prove for Gaussians in the Schwartz space may be of independent interest.Comment: 12 pages, version accepted by JFAA, with various additions and improvement

    Ageing in the critical contact process: a Monte Carlo study

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    The long-time dynamics of the critical contact process which is brought suddenly out of an uncorrelated initial state undergoes ageing in close analogy with quenched magnetic systems. In particular, we show through Monte Carlo simulations in one and two dimensions and through mean-field theory that time-translation invariance is broken and that dynamical scaling holds. We find that the autocorrelation and autoresponse exponents lambda_{Gamma} and lambda_R are equal but, in contrast to systems relaxing to equilibrium, the ageing exponents a and b are distinct. A recent proposal to define a non-equilibrium temperature through the short-time limit of the fluctuation-dissipation ratio is therefore not applicable.Comment: 18 pages, 7 figures, Latex2e with IOP macros; final for
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