This study investigated the effect of silicon (Si) on the resistance of rice plants of the cv. ‘Primavera’ cultivar that were grown in a nutrient solution with 0 (−Si) or 2 mm (+Si) Si to leaf scald, which is caused by Monographella albescens. The leaf Si concentration increased in the +Si plants (4.8 decag/kg) compared to the −Si plants (0.9 decag/kg), contributing to a reduced expansion of the leaf scald lesions. The extent of the cellular damage that was caused by the oxidative burst in response to the infection by M. albescens was reduced in the +Si plants, as evidenced by the reduced concentration of malondialdehyde. Higher concentrations of total soluble phenolics and lignin‐thioglycolic acid derivatives and greater activities of peroxidases (POX), polyphenoloxidases (PPO), phenylalanine ammonia‐lyases (PAL) and lipoxygenases (LOX) in the leaves of the +Si plants also contributed to the increased rice resistance to leaf scald. In contrast, the activities of chitinases and β‐1,3‐glucanases were higher in the leaves of the −Si plants probably due to the unlimited M. albescens growth in the leaf tissues, as indicated by the larger lesions. The results of this study highlight the potential of Si in decreasing the expansion of the leaf scald lesions concomitantly with the potentiation of phenolic and lignin production, and the greater activities of POX, PPO, PAL and LOX rather than simply acting only as a physical barrier to avoid M. albescens penetration.

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In this work three mathematical models for methane steam reforming in membrane reactors were developed. The first one is a steady state, non isothermal, non isobaric and one dimensional model derived from material and energy balances and validated using experimental data from the literature. It is referred as full model. The influence of two different intrinsic kinetics available, as well as, the influence of five important parameters on methane conversion (X CH 4 ) and hydrogen recovery (Y H 2 ) were parametrically evaluated through simulations. The second model, referred as meta-model, was obtained though the response surface technique. This metamodel was included into a constrained optimization problem solved using NPSOL. The third model, referred as a simplified model, takes into account only mass balances from the full model. Using this model, a gradient based method (DIRCOL) was used to perform the optimization of the sum of methane conversion and hydrogen recovery. High methane conversions and hydrogen recoveries were reached through these methodologies. List of symbolsa Constant in Ergun's equation [-] A 0 Pre-exponential factor of the permeability [ mol m 2 s Pa 0.5 ] L.C. Silva, in memoriam. The author passed away in November 2009. 442 L.C. Silva et al. A 1 Heat transfer area between the reaction chamber and the external reactor temperature [m 2 ] A 2 Heat transfer area between the reaction chamber and the permeate side [m 2 ] A m Permeation area of membrane [m 2 ] b Constant in Ergun's equation [-] Cv p Specific heat at constant volume of the permeate side mixture [ J mol K ] Cv r Specific heat at constant volume of the reaction side mixture [ J mol K ] d p Equivalent diameter of catalyst particle [m] E Activation energy [ J mol ] f Friction factor [-] f H 2p Dimensionless flow rate of hydrogen in the permeate side [-] f i Dimensionless flow rate of i component in the reaction side [-] FCH40 = F 0 CH 4 Methane feed flow rate [ mol s ] F H 2p Hydrogen flow rate in the permeate [ mol s ] F i Molar flow rate of component i in the reaction side [ mol s ] FI Molar flow rate of inert or sweep gas [ mol s ] H H 2 Hydrogen enthalpy [ J mol ] J H 2 Hydrogen permeation flux [ mol m 2 s ] L Reactor length [m] M Steam to methane feed flow ratio H 2 O e CH 4 [-] PR0 Inlet reactor pressure [Pa] P R Reactor pressure [Pa] P r Dimensionless reaction pressure [-] P p Permeate pressure [Pa] p H 2 Hydrogen partial pressure in the reaction side [Pa] p H 2p Hydrogen partial pressure in the permeate side [Pa] Q 1 Heat exchanged between the reaction side and external environment [ J s ] Q 2 Heat exchanged between the reaction side and the permeate side [ J s ] r j Rate of the reaction j [ kmol kg cat h ] R Universal gas constant [ J mol K ] Re Reynolds' number [-] T m Membrane temperature [K] T p Dimensionless permeate temperature [-] T r Dimensionless temperature of the reaction side [-] T R Temperature of the reaction side [K] T w External temperature [K] u s Gaseous velocity of the reaction chamber [ m s ] U 1 Overall heat...

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Research on Nonlinear Transmission Lines (NLTLs) has long been carried out to produce oscillating pulses. The radiofrequency (RF) pulses generated by the NLTLs can be radiated by antennas connected to the output of the lines. Possible applications of NLTLs as an RF generator include aerospace radars, telecommunications, battlefield communication disruption, and medical devices. There have been relatively few articles that presented experimental results regarding the extraction and the radiation of the RF signal from NLTLs. This article reports the excellent results obtained with a low voltage lumped capacitive NLTL in which oscillations of the order of 230 MHz were produced and radiated using Double-Ridged Guide (DRG) antennas. The RF signal was extracted using a decoupling circuit based on a Chebyshev high-pass filter. The NLTL was evaluated through time domain and frequency domain analyses of the pulsed RF signal measured on a resistive load connected to the output of the line, as well as on transmitting and receiving by antennas. The LT-SPICE model of the line was implemented and the comparison of simulation and experimental results presented a good agreement.