2,827 research outputs found

    The Michaelis-Menten-Stueckelberg Theorem

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    We study chemical reactions with complex mechanisms under two assumptions: (i) intermediates are present in small amounts (this is the quasi-steady-state hypothesis or QSS) and (ii) they are in equilibrium relations with substrates (this is the quasiequilibrium hypothesis or QE). Under these assumptions, we prove the generalized mass action law together with the basic relations between kinetic factors, which are sufficient for the positivity of the entropy production but hold even without microreversibility, when the detailed balance is not applicable. Even though QE and QSS produce useful approximations by themselves, only the combination of these assumptions can render the possibility beyond the "rarefied gas" limit or the "molecular chaos" hypotheses. We do not use any a priori form of the kinetic law for the chemical reactions and describe their equilibria by thermodynamic relations. The transformations of the intermediate compounds can be described by the Markov kinetics because of their low density ({\em low density of elementary events}). This combination of assumptions was introduced by Michaelis and Menten in 1913. In 1952, Stueckelberg used the same assumptions for the gas kinetics and produced the remarkable semi-detailed balance relations between collision rates in the Boltzmann equation that are weaker than the detailed balance conditions but are still sufficient for the Boltzmann HH-theorem to be valid. Our results are obtained within the Michaelis-Menten-Stueckelbeg conceptual framework.Comment: 54 pages, the final version; correction of a misprint in Attachment

    A Warm-start Interior-point Method for Predictive Control

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    In predictive control, a quadratic program (QP) needs to be solved at each sampling instant. We present a new warm-start strategy to solve a QP with an interior-point method whose data is slightly perturbed from the previous QP. In this strategy, an initial guess of the unknown variables in the perturbed problem is determined from the computed solution of the previous problem. We demonstrate the effectiveness of our warm-start strategy to a number of online benchmark problems. Numerical results indicate that the proposed technique depends upon the size of perturbation and it leads to a reduction of 30–74% in floating point operations compared to a cold-start interior-point method

    Modeling Routing Overhead Generated by Wireless Proactive Routing Protocols

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    In this paper, we present a detailed framework consisting of modeling of routing overhead generated by three widely used proactive routing protocols; Destination-Sequenced Distance Vector (DSDV), Fish-eye State Routing (FSR) and Optimized Link State Routing (OLSR). The questions like, how these protocols differ from each other on the basis of implementing different routing strategies, how neighbor estimation errors affect broadcast of route requests, how reduction of broadcast overhead achieves bandwidth, how to cope with the problem of mobility and density, etc, are attempted to respond. In all of the above mentioned situations, routing overhead and delay generated by the chosen protocols can exactly be calculated from our modeled equations. Finally, we analyze the performance of selected routing protocols using our proposed framework in NS-2 by considering different performance parameters; Route REQuest (RREQ) packet generation, End-to-End Delay (E2ED) and Normalized Routing Load (NRL) with respect to varying rates of mobility and density of nodes in the underlying wireless network

    An exergy approach to efficiency evaluation of desalination

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    This paper presents an evaluation process efficiency based on the consumption of primary energy for all types of practical desalination methods available hitherto. The conventional performance ratio has, thus far, been defined with respect to the consumption of derived energy, such as the electricity or steam, which are susceptible to the conversion losses of power plants and boilers that burned the input primary fuels. As derived energies are usually expressed by the units, either kWh or Joules, these units cannot differentiate the grade of energy supplied to the processes accurately. In this paper, the specific energy consumption is revisited for the efficacy of all large-scale desalination plants. In today's combined production of electricity and desalinated water, accomplished with advanced cogeneration concept, the input exergy of fuels is utilized optimally and efficiently in a temperature cascaded manner. By discerning the exergy destruction successively in the turbines and desalination processes, the relative contribution of primary energy to the processes can be accurately apportioned to the input primary energy. Although efficiency is not a law of thermodynamics, however, a common platform for expressing the figures of merit explicit to the efficacy of desalination processes can be developed meaningfully that has the thermodynamic rigor up to the ideal or thermodynamic limit of seawater desalination for all scientists and engineers to aspire to

    IGUANA Architecture, Framework and Toolkit for Interactive Graphics

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    IGUANA is a generic interactive visualisation framework based on a C++ component model. It provides powerful user interface and visualisation primitives in a way that is not tied to any particular physics experiment or detector design. The article describes interactive visualisation tools built using IGUANA for the CMS and D0 experiments, as well as generic GEANT4 and GEANT3 applications. It covers features of the graphical user interfaces, 3D and 2D graphics, high-quality vector graphics output for print media, various textual, tabular and hierarchical data views, and integration with the application through control panels, a command line and different multi-threading models.Comment: Presented at the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 6 pages LaTeX, 4 eps figures. PSN MOLT008 More and higher res figs at http://iguana.web.cern.ch/iguana/snapshot/main/gallery.htm

    High frequency induction of somatic embryos and plantlet regeneration from nodal explants of Hygrophila spinosa T. Anders

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    An efficient protocol is described for the rapid in vitro plant regeneration of a medicinally important plant, Hygrophila spinosa through direct somatic embryogenesis from nodal explants excised from 4 week old aseptic seedlings. Somatic embryos differentiated directly from nodal explants on Murashige and Skoog (MS) medium supplemented with 1.0 ìM 6- benzyladenine (BA) after 1 week of culture. The highest number (110.40 ± 3.55) of somatic embryos were recorded on MS medium supplemented with 1.0 ìM BA and 0.5 ìM NAA, growth regulator free half strength MS medium was found suitable for maturation and conversion of somatic embryos into complete plantlets. The well developed in vitro regenerated plantlets were successfully established in pots containing garden soil and grown in agreenhouse with 85% survival rate. The regenerants present an appearance similar to the seedlings obtained from normal seeds. The described method can be successfully employed for large scale multiplication and long term in vitro conservation of H. spinosa

    The association between accruals and stock return following IFRS3

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    The purpose of this study is to investigate the correlation between accruals and stock return and further the quality of accounting accruals shown in financial statements for shareholders to predict their future returns. This study uses an inimitable location which is provided by FRS3 in the UK to highlight the well-documented accrual anomaly as important components of financial performance to help the users to understand the archived performance of a firm. Specifically, this paper focuses on the accrual anomaly phenomenon in the UK on the adoption of FRS No. 3 for a period from 2008 to 2017. Our result shows that stock returns can be predicted by accruals attributable to accounting misrepresentations. Generally, our findings support the information disclosure due to FRS No. 3. Also, the results are consistent with increased accounting disclosure to help investors protect themselves from inefficiencies and to encourage them to be aware of accurate stock prices in the market
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