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91.
Countercurrent reactor design and flowsheet for iodine-sulfur thermochemical water splitting process
Jean Leybros Philippe Carles Jean-Marc Borgard 《International Journal of Hydrogen Energy》2009,34(22):9060-9075
A conceptual design is presented for the I/S process for the production of hydrogen using a high-temperature nuclear heat source to split water. The process includes a countercurrent reactor being developed by CEA within the framework of an international collaboration (I-NERI project) with DOE at General Atomics (San Diego, CA). A ProsimPlus? model of the flowsheet indicates 600 kJ high-temperature heat and 69 kJ electric power are consumed per mole of H2 product (with an assumed pressure of 120 bars). The net thermal efficiency would be 38% (HHV basis) if electric power is available at a conversion efficiency of 45%. 相似文献
92.
Alessandri A. Parisini T. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》1997,27(6):750-757
This paper deals with a general methodology for system greybox identification. As is well-known, the tuning of accurate models of real plants (obtained, for instance, by using the physical knowledge of the plants and the technicians' expertise), on the basis of the measures provided by the available sensors, remains a challenge. In this paper, a tuning methodology for complex large-scale models, is presented. The proposed technique is based on the suitable use of neural networks and specific stochastic-approximation algorithms. It is therefore possible to design a simulator that can be connected in parallel with a real plant, thus providing the plant technician with information about inaccessible variables that are useful for supervision purposes. The proposed methodology is applied to a section of a real 320 MW power plant. Simulation results on the tuning algorithm show the effectiveness of the approach 相似文献
93.
Mahmoud Sitohy Michle Dalgalarrondo Marie Nowoczin Bernard Besse Sylviane Billaudel Thomas Haertl Jean-Marc Chobert 《International Dairy Journal》2008,18(6):658-668
The antiviral activity of esterified whey proteins (IC50=20–40 μg mL−1) observed against poliovirus type-1 and Coxsackie virus B6 infecting Vero cells depended on five factors (in order of importance): concentration of esterified proteins, multiplicity of infection, duration of incubation, timing of esterified proteins addition after infection, and extent of esterification of proteins. Renewal of cell growth medium after 24 h of incubation with new medium containing the same amount of esterified proteins enhanced the anti Coxsackie virus effect. Difference between start of infection of the reporter Vero cells and the time of addition of esterified proteins significantly decreased their antiviral efficacies. The poliovirus titer reduced gradually in response to the increase of the concentrations of esterified proteins. The relative amounts of viral RNA were less affected by the esterified proteins concentration than was the virus infectious titer, indicating that inhibitory proteins may slow down viral multiplication, yielding reduced amounts of viral RNA. 相似文献
94.
How do people work when they are collaborating to write a document? What kind of tools do they use and, in particular, do they resort to groupware for this task? Forty-one people filled out a questionnaire placed on the World Wide Web. In spite of the existence of specialized collaborative writing tools, most respondents reported using individual word processors and email as their main tools for writing joint documents. Respondents noted the importance of functions such as change tracking, version control, and synchronous work for collaborative writing tools. This study also confirmed the great variability that exists between collaborative writing projects, whether it be group membership, management, writing strategy, or scheduling issues. 相似文献
95.
Boundary variational formulations and numerical solution techniques for unilateral contact problems 总被引:1,自引:1,他引:0
In this paper the numerical solution of the elastic frictionless contact problem is obtained by means of boundary discretization techniques. Variational formulations in terms of boundary tractions are given in presence of both bilateral and unilateral constraints. The discretization of the boundary functional is examined from the point of view of the theory of approximation and it is proved that the coerciveness (but not the symmetry) of the continuum problem is preserved when standard B.E.Ms are employed. As a consequence, the contact problem can be cast as a L.C.P. having, as coefficient matrix, a generally non symmetric P matrix. A simple, but meaningful example is discussed in some detail. 相似文献
96.
Jean-Marc Maréchal 《Polymer》2004,45(14):4641-4646
Various ‘ate’ complexes formed by reaction of alkali metal (Li, Na, K) derivatives and alkyl metals (Mg, Al, Zn) were used as initiator for the styrene anionic polymerization in hydrocarbon media and their influence on polystyrene microstructure has been investigated. A strong dependence of the polymer tacticity on both the nature of the alkali metal and of the associated metal alkyl used is observed. Binary systems like potassium derivatives/dialkylmagnesium yield isotactic-rich polystyrene. Eighty-five percent isotactic polystyrene (mm triad) is obtained in methylcyclohexane at −40 °C with the potassium tert-butoxide/n,s-dibutylmagnesium system. The characteristics of solubility of the stereoregular polystyrenes are in agreement with isotactic polystyrene chains containing some stereostructural defects and suggest that one single type of isospecific propagating centres is operating during the polymerization. When lithium or sodium derivatives are used in association to dialkylmagnesium instead of a potassium derivative, a strong decrease of the isotacticity is observed. The influence, on the extent of stereoregulation, of other parameters of these initiating systems as well as that of the solvent has also been investigated. The stereoregulation mechanisms involved in these styrene anionic polymerizations may be related to styrene insertion into carbon-metal bonds of the ‘ate’ complexes with a covalent character. 相似文献
97.
This paper aims to explain how Electricité de France as owner and plant operator of nuclear power stations generating wastes has improved its management to meet its obligations which are the protection of man and preservation of the environment. Beyond the technical aspects (reducing liquid effluents and sorting waste at source for example) which have led to a significant decrease of radioactive waste volumes, continued success depends on planned management initiatives. These include computerized waste management and will be completed finally by setting up centralized treatment methods such as fusion and incineration. To provide packages in accordance with French specifications for final near-surface disposal, EDF has applied the same quality approach to radioactive waste management as that used for other operating actions. Management decisions taken mainly coordinate around two axes, namely "Accountability" and "organisation". 相似文献
98.
Sahyoun W Duchamp JM Benech P 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(10):2162-2170
Coupled resonator filters (CRFs) are the new generation of BAW filters recently designed for the front-end modules of mobile transmission systems. Looking for designers' requirements, CRF devices have been characterized and modeled. The model based on equivalent circuits relies on material constants such as stiffness and electro-coupling coefficients, and works only for linear-mode propagation. Because of their positions between antennas and power amplifiers, they often work under high RF power, inducing nonlinear response in the AlN piezoelectric layer. In this work, we analyze for the first time the nonlinear behavior of AlN material particularly for coupled BAW resonators. To characterize the nonlinear effects in CRFs, we measure the 1-dB gain compression point (P1dB) and the intercept point (IP(3)). Then, we develop a nonlinear model of CRFs using harmonic balance (HB) simulation in commercially available software. The HB environment allows fitting simulations to measurements in terms of P(1dB) and IP(3). We find that a high RF power induces nonlinear changes in the material constants' real parts: elastic stiffness c(33) (4.9%), piezoelectric e(33) (17.4%), and permittivity ?(33) (5.2%). These nonlinear variations of material constants describe the nonlinear behavior of CRF devices using the same deposit process for AlN material. 相似文献
99.
We developed an original method to measure nitrification rates at different depths of a vertical flow constructed wetland (VFCW) with variable contents of organic matter (sludge, colonized gravel). The method was adapted for organic matter sampled in constructed wetland (sludge, colonized gravel) operated under partially saturated conditions and is based on respirometric principles. Measurements were performed on a reactor, containing a mixture of organic matter (sludge, colonized gravel) mixed with a bulking agent (wood), on which an ammonium-containing liquid was applied. The oxygen demand was determined from analysing oxygen concentration of the gas passing through the reactor with an on-line analyzer equipped with a paramagnetic detector. Within this paper we present the overall methodology, the factors influencing the measurement (sample volume, nature and concentration of the applied liquid, number of successive applications), and the robustness of the method. The combination of this new method with a mass balance approach also allowed determining the concentration and maximum growth rate of the autotrophic biomass in different layers of a VFCW. These latter parameters are essential inputs for the VFCW plant modelling. 相似文献
100.
详细介绍了泰国曼谷南外环线上主垮500 m的SOBRR叠合梁斜拉桥的主要施工方法,如节段的安装,悬臂施工主梁的水平锚固、边墩和边主梁联结、边跨平衡重及主跨的合龙等. 相似文献