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The article presents the simulation and laboratory tests of multi-pulse rectifiers with magnetically coupled reactors, connected to the power grid and cooperating with an active parallel filter (APF). In the study, two types of multi-pulse AC/DC rectifiers were compared, namely 12- and 24-pulse rectifiers. It presents the operating principle and the results of the simulation and laboratory tests. The considered systems enable the reduction of undesired high harmonics in the power supply grid current. For the manufacture of multi-pulse rectifiers, assemblies of magnetically coupled spring reactors configured in the TDS? system were used. [ABSTRACT FROM AUTHOR]

Highlights • First results of Canadian Nuclear Laboratories' new PT-HWR transient simulation toolset. • SALOME-based coupling of ARIANT (formerly known as CATHENA4) and NESTLE-C. • Results for a stylized 20% LBLOCA are presented. Abstract Canadian Nuclear Laboratories has developed a toolset of coupled reactor transient simulation codes for pressure tube heavy water reactors. This paper presents the first demonstration of the toolset's capabilities, using a hypothetical 20% reactor inlet header break (critical break) scenario. This scenario induces strong feedback between thermalhydraulic and reactor physics phenomena, owing to a positive coolant voiding coefficient. The scenario was simulated using the advanced thermalhydraulics code ARIANT and the reactor physics code NESTLE-C, coupled together using the SALOME platform. This paper summarizes recent advances in ARIANT, the coupling methodology, and the results of the transient simulation. [ABSTRACT FROM AUTHOR]

The history of formation and practical realization of the concept of the coupled reactor facilities that was embodied in the domain of aperiodic pulsed reactors is traced back. It is demonstrated that the application of the concept of coupled reactor facilities extends significantly the potentialities of the experiments executed on reactors. [ABSTRACT FROM AUTHOR]

Constitutively active mutants (CAMs) of G-protein-coupled receptors (GPCRs) cause various kinds of diseases. Rhodopsin, a light-absorbing GPCR in animal retinas, has retinal as an endogenous ligand; only very low levels of activation of G-protein can be obtained with the ligand-free opsin. However, the CAM of opsin activates G-protein much more efficiently than the wild type, but the mechanism underlying this remains unclear. The present work revisits the constitutive activity of rhodopsin from the standpoint of conformational dynamics. Single-molecule observation of the M257Y mutant of bovine rhodopsin demonstrated that the switch between active and inactive conformations frequently occurred in M257Y opsin, and frequent generation of the active state results in the population shift toward the active state, which accounts for the constitutive activity of M257Y opsin. Our findings demonstrate that the protein function has a direct connection with the structural dynamics. [ABSTRACT FROM AUTHOR]

The authors investigate pinning synchronisation for two spatial diffusion coupled reaction-diffusion neural networks under undirected and directed topologies. Combined with stability theory, some inequalities and Lyapunov functional method, several sufficient conditions are derived to assure the synchronisation of the considered networks by designing appropriate pinning controllers. It should be pointed out that a new type of spatial diffusion feedback pinning controller is designed in this paper. The correctness of the obtained results is confirmed by two simulation examples. [ABSTRACT FROM AUTHOR]

In this paper, an optimized membrane-assisted thermally coupled reactor, as well-known equipment for process intensification (PI), is proposed for simultaneous production of highly-valuable xylenes and pure hydrogen. In the proposed configuration, transalkylation process (exothermic reaction) and dehydrogenation of methylcyclohexane (endothermic reaction) take place simultaneously in two different sides, and a hydrogen perm-selective Pd/Ag membrane is utilized to separate pure hydrogen from the endothermic side. A comprehensive reaction network is applied for the exothermic side with the aim of providing a reliable reactor model. The operating conditions of the membrane-assisted thermally coupled reactor are optimized using Differential Evolution (DE) method with 10 decision variables. The model results of conventional reactor are validated with the plant data and a reasonable agreement is achieved. In order to verify the performance of the membrane-assisted thermally coupled reactor configuration, the modeling results are compared with that of the conventional reactor, which reveals that the optimized thermally coupled membrane reactor results in more xylenes yield and lower temperature in exothermic side. [ABSTRACT FROM AUTHOR]

Coupled reactors and the coupling features of large or heterogeneous core reactors can be investigated with the Avery’s theory; however, the complex geometries that are often encountered in association with coupled reactors, require a detailed geometry description that can be easily provided by modern Monte Carlo (MC) codes. The results presented in this paper show that the MC code SERPENT has been successfully modified in order to compute the needed quantities like coupling coefficients. Moreover, the capability for calculating sensitivities to the quantities of interest for coupling reactors has been developed and implemented in SERPENT. [ABSTRACT FROM AUTHOR]

FINIX is a recently developed fuel behaviour module that is designed to provide "simple but sufficient" descriptions of the most essential fuel behaviour phenomena in multiphysics simulations. In such simulations, it is possible to obtain significant improvement in the feedback to neutronics or thermal hydraulics modelling even with a relatively simple fuel performance model. In this work, FINIX is used as an internal fuel behaviour module both in reactor physics and in reactor dynamics codes to simulate coupled behaviour in fast transient scenarios. With the Monte Carlo reactor physics code Serpent we model a prompt transient in a VVER-1000 pin cell, and with the reactor dynamics code HEXTRAN, a control rod ejection accident in a VVER-440 reactor. [ABSTRACT FROM AUTHOR]

Highlights: [•] Coupling of a tubular reactor and SMB chromatography for continuous production. [•] Modeling of the coupled system using experimentally determined parameters. [•] Dynamic optimization of SMB chromatography. [•] Integrated design of the coupled reactor–separator process. [•] Experimental validation of the coupled process. [Copyright &y& Elsevier]

we present a first supercloseness analysis for higher order FEM/LDG coupled method for solving singularly perturbed convection-diffusion problem. Based on piecewise polynomial approximations of degree k (k ≥ 1), a supercloseness property of k + 1/2 in DG norm is established on S-type mesh. Numerical experiments complement the theoretical results. [ABSTRACT FROM AUTHOR]

Abstract: The concept of integrated thermally double coupled reactor is proposed as an alternative for reduction of environmental emissions and consumption of energy, minimizing capital and operating costs and increasing production and efficiency of the processes. The goal of this study is simultaneous production of hydrogen, methanol and high octane gasoline in a novel thermally double coupled reactor. This configuration is a multi-tubular reactor in which the required heat for the endothermic decalin dehydrogenation is provided by two exothermic reactions: methanol production and Fisher–Tropsch synthesis (FTS). Differential evolution (DE) method is also used in order to find the optimal operating conditions for the enhancement of methanol mole fraction as well as gasoline yield in the outlet of thermally double coupled reactor. The results of methanol production in the optimized thermally double coupled reactor are compared with the conventional methanol synthesis reactor. This comparison shows that in addition to higher methanol productivity in the optimized thermally double coupled reactor (10.52% increase compared with conventional methanol synthesis reactor), hydrogen, naphthalene and gasoline are also produced as an additional valuable products in a favorable mode. [Copyright &y& Elsevier]

Abstract: In this paper, a thermally double-coupled two-membrane reactor for simultaneous production of methanol, hydrogen and dimethylether (DME) by employing Pd/Ag membranes in co-current mode has been investigated. In this novel multi-tubular reactor configuration, cyclohexane dehydrogenation as an endothermic reaction has coupled with two exothermic reactions of methanol production and direct DME synthesis from syngas. Two Pd/Ag membranes are used for improving the efficiency of hydrogen production and other products in exothermic sides by separation of hydrogen from unconverted outputs of exothermic sides that are recycled to the reactor. A steady state heterogeneous catalytic reaction model is applied to analyze the performance of thermally double-coupled two-membrane reactor and comparison of the result with corresponding predictions for a conventional methanol reactor, thermally coupled reactor (coupling of methanol synthesis with cyclohexane dehydrogenation only) and thermally double coupled reactor. Modeling results show that by employing this novel configuration, methanol yield reaches to 0.4017 in comparison with 0.3885, 0.3735 and 0.362 for conventional methanol reactor, thermally double coupled reactor and thermally coupled reactor respectively. Also methanol production increases 3.39%, 7.03% and 10.94% compared with conventional methanol reactor, thermally double coupled reactor and thermally coupled reactor respectively. Simulation results illustrate that by using Pd/Ag membranes, DME production raises from 277.24 kmol h−1 in thermally double coupled reactor to 325.3 kmol h−1 in thermally double-coupled two-membrane reactor. Additionally, hydrogen production in endothermic side of thermally double coupled reactor is enhanced from 1076 to 1219 kmol h−1 in thermally double-coupled two-membrane reactor. [Copyright &y& Elsevier]

The objective of this paper is the simulation and analysis of the BoilingWater Reactor (BWR) lower head during a severe accident. The COUPLE computer code was used in this work to model the heatup of the reactor core material that slumps in the lower head of the reactor pressure vessel. The prediction of the lower head failure is an important issue in the severe accidents field, due to the accident progression and the radiological consequences that are completely different with or without the failure of the Reactor Pressure Vessel (RPV). The release of molten material to the primary containment and the possibility of steam explosion may produce the failure of the primary containment with high radiological consequences. Then, it is important to have a detailed model in order to predict the behavior of the reactor vessel lower head in a severe accident. In this paper, a hypothetical simulation of a Loss of Coolant Accident (LOCA) with simultaneous loss of off-site power and without injection of cooling water is presented with the proposal to evaluate the temperature distribution and heatup of the lower part of the RPV. The SCDAPSIM/RELAP5 3.2 code was used to build the BWR model and conduct the numerical simulation. [ABSTRACT FROM AUTHOR]