Moshe Sheintuch

Technion – Israel Institute of Technology | technion · Faculty of Chemical Engineering

We classify the dynamic patterns that emerge in charging or discharging of Li‐ion batteries, under galvanostatic conditions, using simulations of the two‐phase one‐dimensional (1D) porous electrode model. This work examines the effect of the exchange current function, R0(X), which expresses the nature of kinetics. This extends our previous study wi...

We classify the dynamic patterns that emerge in charging or discharging of Li-ion batteries, under galvanostatic conditions, using simulations of the two-phase 1D porous model. This work examines the effect of exchange current function, R0(X), which expresses the nature of kinetics and extends our previous study limited to R0=1 for which the same p...

A pattern of sequential group-by-group charging or discharging, of Li batteries with phase-separation thermodynamics, was detected by numerical simulations and justified by several experiments published in literature. The present work is the first to quantitatively predict the main characteristics of the sequential symmetry breaking (SB) events, su...

In loop reactors the system is composed of several reactor units that are organized in a loop and the feeding takes place at one of several ports with switching of the feed port. In its simplest operation a pulse is formed and rotates around it, producing high temperatures which enable combustion of dilute streams. A limiting model with infinite nu...

The sequential group-by-group charging/discharging in Li batteries with phase-separation thermodynamics was detected by numerical simulations and justified by several experiments published in literature. The present work is the first to quantitatively predict the main characteristics of the sequential symmetry breaking (SB) such as the average Li c...

While permeance inhibition due to competitive co-adsorption of CO, hydrogen and other species have been documented and analyzed in Pd or Pd-alloy membrane separators and reactors, the effect of reaction on the Pd surface has not been analyzed. The contribution of the Pd membrane to the overall reaction rate of the catalyst packed bed in the reactor...

Membranereactorsforthepro ductionofpurehydrogenarecomplexsystemswhosep erformanceisdeterminedbytheinterplayb etweentransp ortbycon-vectionanddisp ersionwithinthepackedb ed,hydrogenp ermeationacrossthemembrane,andthereactionkinetics.Muche�orthasb eendevotedtothedevelopmentofsimpli edmo delsthatcombineanadequatedescriptionofthesystem,whilemaintaining...

The main purpose of this work was to demonstrate that steam reforming of methylal (dimethoxymethane, MA), even at low steam to MA ratios, can be used for thermal recuperation of the energy of ICE exhaust gas. This work confirms that high conversion to H2 and CO can be achieved at temperatures above 450 oC on alumina-supported Pt (0.1%) or Cu cataly...

Due to its strong exothermicity and strong reactant inhibition, the FTS is a great candidate for employing a cross-flow reactor, in which the reactants are distributed along the reactor. The desired temperature, which is 480–500 K on a Co catalyst, aimed to achieve reasonable conversion with reasonable selectivity, is achieved by cooling, either by...

This article offers a comprehensive overview of research on fuel reforming in internal combustion engines (ICE). It includes a historical perspective of research in this field, a discussion on the considerations to be made prior to choosing a primary fuel for reforming purposes, and the main processes in fuel reforming. Steam reforming offers a mod...

Many studies have demonstrated an inhibition of hydrogen permeance through a Pd or Pd-alloy membrane due to competitive adsorption of CO, ammonia and other species. Several corrections to Sieverts’ law were suggested to account for these effects, based on a Langmuir isotherm, but they all suffer from certain drawbacks as detailed below. We derive a...

The main factors affecting the design of a Propane Dehydrogenation Membrane Reactor (PDH MR) are the deactivation of the catalyst and of the membrane due to coking. Both apparently accelerate with increasing temperature or pressure and with depletion of hydrogen; i.e., with conditions that improve conversion in a membrane reactor. Recent studies of...

The kinetics and diffusion effects of methanol steam reforming reaction over commercial Cu/ZnO/Al2O3 catalyst was studied for steam to methanol (S/M) ratios of 0 to 1 and pressures below 6 bar. Our objective is the development of a novel high-pressure propulsion technology based on the concepts of thermochemical recuperation (TCR) and onboard hydro...

Several studies on membrane reactors for hydrogen production have shown that the permeation of hydrogen may be inhibited by the competitive adsorption of one or more of the reactants. This adsorption-inhibition effect, often accounted for in rate expressions of catalytic reactions, may induce the existence of multiple steady state solutions. In thi...

One of the main tasks in the analysis of models of biomolecular networks is to characterize the domain of the parameter space that corresponds to a specific behavior. Given the large number of parameters in most models, this is no trivial task. We use a model of the embryonic cell cycle to illustrate the approaches that can be used to characterize...

While previous studies experimentally demonstrated sustained operation in a loop reactor (using ethylene or methane combustion), and analyzed the single-reaction case and suggesting a proper control scheme, an actual implementation of VOC combustion will involve several reactants of varying concentrations. Here we study the dynamics and design impl...

The kinetic and dynamic behavior of the methanol steam reforming (MSR) over CuO/ZnO/Al2O3 catalyst were followed at various steam to carbon (S/C) ratio using temperature ramping and steady state input conditions. The data is required for designing a methanol reformer-internal combustion engine (ICE) system, utilizing the reforming products as fuel...

While previous studies experimentally demonstrated that loop reactor (LR) can be sustained with a lean feed (using ethylene combustion) and have analyzed the single-reaction adiabatic case, this work analyzes the effects of heat loss and of reactor size to determine the leanest stream (expressed in terms of adiabatic temperature rise ΔTlim) that wi...

A process for producing hydrogen from natural gas, said process comprises the steps of: (i) providing an autothermal heat exchanger packed-bed membrane reformer (APBMR) comprising: (a) an elongated external gas oxidation compartment comprising an inlet, an outlet and packed oxidation catalyst particles, said inlet and outlet being located each at o...

This article presents experimental results of an autothermal scaled -down system for H-2 production. Pure atmospheric pressure 11,, separated in situ by Pd-Ag membranes, is produced by steam reforming (SR) of methane, ethanol, or glycerol. Oxidizing the SR effluents in a separate compartment supplies the heat. The oxidation feed is axially distribu...

Microkinetic models of methane steam reforming (MSR) over bare platinum and rhodium (111) surfaces are analyzed in present work using calculated rate constants. The individual rate constants are classified into three different sets: (i) rate constants of adsorption and desorption steps of CH4, H2O, CO and of H2; (ii) rate constants of dissociation...

This paper presents experimental results of an autothermal scaled-down system for H2 production. Pure atmospheric pressure H2, separated in situ by Pd-Ag membranes, is produced by steam reforming (SR) of methane, ethanol or glycerol. Oxidizing the SR effluents in a separate compartment supplies the heat. The oxidation feed is axially distributed to...

A kinetic model of propane dehydrogenation on a Pt,Sn/Mg(Al)O is presented, accounting for product distribution due to main and side reactions, for deactivation rates and for diffusion resistance. Parameters were estimated from steady state experiments at varying pressure and from temperature-programmed experiments, and are compared with previous m...

We discuss various designs for scaled down membrane steam reformer for generating pure hydrogen onboard or in a hydrogen fuel station, motivated by the expectation of using hydrogen as an energy carrier, mainly to power the energy efficient and environmentally friendly Proton Exchange Membrane Fuel Cells (PEMFC). Pure H2 separation is achieved by P...

Pd-based membranes have potential applicability in the PDH process to selectively remove hydrogen. In the current work, H2 flux values and coke formation kinetics applying representative gaseous feed mixtures under varying operating conditions are evaluated and modelled. From these experiments, it is clear that coke formation is very likely under t...

Design of a selective membrane reactor requires a kinetic model (or rate expression) for transport through the membrane and the effects of various co-adsorbates. In many cases the membrane area, the most expensive component in the process, is determined by the hydrogen transport rate (permeance) while its sensitivity to the catalytic reaction rate...

In a system of parallel reversible reactions, separating the corresponding product can enhance a desired reaction. If the same product is produced in several reactions, its concurrent separation enhances the reaction with the higher stoichiometry. Here we demonstrate this effect by separating hydrogen from ethanol during steam reforming in a Pd mem...

This paper presents a project named CoMETHy (Compact Multifuel-Energy to Hydrogen converter) co-funded by the European Commission under the Fuel Cells and Hydrogen Joint Undertaking (FCH JU). The project is developing an innovative steam reformer for pure hydrogen production to be powered by Concentrating Solar Power (CSP) plants using molten salts...

An activated carbon cloth-supported bimetallic Pd—Cu nanocatalyst is disclosed comprising about 1 wt % Pd and about 0.35-0.45 wt % Cu and having a surface Cu/Pd metal ratio of about 8-10 m2/m2. The nanocatalyst is capable of removing nitrate and/or nitrite from wastewater with a high selectivity to nitrogen.

The design of an on-board autothermal membrane reactor producing pure hydrogen at atmospheric pressure, while recuperating heat, is analyzed mathematically. The suggested design incorporates two reactors exchanging heat; an endothermic methane steam-reforming (MSR) reactor embedding Pd membranes to separate pure H2, and an exothermic methane oxidat...

Measurements in a membrane methane reformer packed with catalytic (Pt(3)Ni(10)/CeO2) foams and equipped with a 175 cm(2) Pd membrane showed that high conversion and high hydrogen recovery can be achieved with sweep flow and high pressures (over 90% conversion and over 80% H-2 recovery at 525 degrees C for 0.25 NL/min CH4 feed flow). Increasing pres...

Approximate models are proposed to simulate the transmembrane hydrogen flux in an empty membrane separator. The hydrodynamic field is constructed under the assumption of constant density with a single unknown parameter – the normal wall velocity (vw). The 2-D concentration profiles are derived using a known velocity distribution. The problem is clo...

We characterize turbulent flow from radial impellers in stirred tanks, formulating semi-analytical predictions based on conventional turbulent-jet theory and the general framework of scalar dispersion in turbulent shear flows. This work introduces a novel formulation of the radial-discharge flow as two separate spatial regions along the radial axis...

Control strategy for suppression of spiral-wave in a 2-D model of an excitable media is developed with application to the cardiac system. The controller which incorporates a finite number of actuators (electrodes) assures the establishment of traveling plane behavior using the following strategy in the context of cardiac system: a small current tha...

We calculate the rate of hydrogen transfer through a Pd and a Pd/Ag selective membrane using transition state theory with adsorption and activation energies calculated by DFT and nudge elastic band methods. The flux through the membrane bulk was evaluated using Fick's law with the diffusivity constant calculated from energetic barriers in the diffu...

This paper describes a model for the simulation of the joint operation of internal combustion engine (ICE) with methanol reformer when the ICE is fed by the methanol steam reforming (SRM) products and the energy of the exhaust gases is utilized to sustain endothermic SRM reactions. This approach enables ICE feeding by a gaseous fuel with very favor...

The interaction of convection and reaction front propagation is known to exhibit a nonlinear phenomenons in the case of an adverse flow, i.e., when the gas velocity (V=[u,v]') and the front velocity (Vf) are of opposite directions. This was demonstrated both experimentally and analytically under isothermal conditions with Vf constant independent of...

The rate constant (W) of catalytic dissociation of a methane molecule to adsorbed CH3 and H and its temperature dependence are studied in the framework of a tunneling model which considers the reaction as a result of quantum transitions between discrete vibrational energy levels of an initial C–H bond in methane and energy continuum of the dissocia...

Activated dissociative adsorption of a hydrogen molecule on metal surfaces is studied in the framework of the precursor mediated dissociation (PMD) mechanism according to which the dissociation proceeds through a molecular-adsorbed state (precursor) which then dissociates to H atoms. The PMD activation energies and rate constants are calculated by...

This paper presents 7FP project named CoMETHy (Compact Multifuel-Energy to Hydrogen converter) co-funded by the European Commission under the Fuel Cells and Hydrogen Joint Undertaking (FCH JU). The project is developing an innovative steam reformer for pure hydrogen production to be powered by Concentrating Solar Power (CSP) plants using molten sal...

Simulations and analysis of transversal patterns in a homogeneous three-dimensional (3-D) model of adiabatic or cooled packed bed reactors (PBRs) catalyzing a first-order exothermic reaction were presented. In the adiabatic case the simulation verify previous criteria, claiming the emergence of such patterns when (ΔTad/ΔTm)/(PeC/PeT) surpasses a cr...

We model and simulate gas flow through nanopores using a single-walled carbon nanotube model. Efficient protocols for the simulation of methane molecules in nanotubes are developed and validated for both the self-diffusivity, following a pulse perturbation, and for the transport diffusivity in an imposed concentration gradient. The former is found...

A tunnel mechanism of OH dissociation reaction on metal surfaces is suggested and analyzed. Expressions for the rate constant and the activation energy are obtained by calculating the transition probability on semiempirical potential energy surfaces in the framework of the nonadiabatic perturbation theory. The analysis of the transition probability...

An overall formulation of an adiabatic approach, which combines adsorption characteristics of reactants and products with an analytical method of searching for the saddle point (SP) on semi-empirical adiabatic potential energy surface (APES), is presented for studying surface reactions kinetics. The following cases are analyzed: (i and ii) breaking...

This paper develops a new model-based control aimed to stabilize the propagation velocity of electrical pulses circulating in an one-dimensional ring model of the cardiac tissue. The controller induces small currents using electrodes placed along the ring. This current responds to the discrepancy between the pulse front voltage, measured at an elec...

Alkenes (olefins) production by the catalytic dehydrogenation of light alkanes (paraffins) is an alternative to conventional heavy hydrocarbons cracking. Alkenes are important intermediate materials for a variety of applications and the catalytic alkanes dehydrogenation allows for their production from low-cost feedstocks, such as natural gas. The...

We derive a new criterion for transversal instability of planar fronts based on the bifurcation condition dVf/dK|K=0 = 0, where Vf and K are the front velocity and its curvature, respectively. This refines our previously obtained condition, which was formulated as α = (ΔTadPeT)/(ΔTmPeC) > 1 to α > 1 + |δ|, where ΔTad and ΔTm are the adiabatic and m...

An autothermal membrane reformer comprising two separated compartments, a methane oxidation catalytic bed and a methane steam reforming bed, which hosts hydrogen separation membranes, is optimized for hydrogen production by steam reforming of methane to power a polymer electrolyte membrane fuel cell (PEMFC) stack. Capitalizing on recent experimenta...

The transport of gas mixtures through molecular-sieve membranes such as narrow nanotubes has many potential applications, but there remain open questions and a paucity of quantitative predictions. Our model, based on extensive molecular dynamics simulations, proposes that ballistic motion, hindered by counter diffusion, is the dominant mechanism. O...

We consider the stabilization of a rotating temperature pulse traveling in a continuous asymptotic model of many connected chemical reactors organized in a loop with continuously switching the feed point synchronously with the motion of the pulse solution. We use the switch velocity as control parameter and design it to follow the pulse: the switch...

Formation of transversal patterns in a 3D cylindrical reactor is studied with a catalytic reactor model in which an exothermic first-order reaction of Arrhenius kinetics occurs with a variable catalytic activity. Under these oscillatory kinetics, the system exhibits a planar front (1D) solution with the front position oscillating in the axial direc...

Loop reactors may compete with other heat recuperating technologies, like reverse-flow reactors, for catalytic abatement of low-concentration volatile organic compounds (VOC), with the advantage that unconverted flashes are avoided. These were recently demonstrated experimentally by the authors. The main goal of this research is to extend this conc...

We review recent results on pattern selection in the one- or two-dimensional reaction-diffusion system xt - Δx = f(x, y, λ), y t = εg(x, y), subject to global (〈x〉 = x 0) or long-range interaction; the source functions may be realistic kinetic functions or simple cubic or quintic f(x) functions for which the system admits inversion symmetry. This r...

We have recently showed the formation of transversal patterns in a 3D cylindrical reactor in which an exothermic first-order reaction of Arrhenius kinetics occurs with variable catalytic activity. Under these oscillatory kinetics, the system exhibits a planar front (1D) solution, with the front position oscillating in the axial direction, while in...

Stability of planar "frozen" fronts propagating through a cylindrical shell reactor in reaction-diffusion and reaction-diffusion-advection systems is studied numerically using the reactor perimeter (S) as a bifurcation parameter. For both systems rigid rotating patterns superimposed on axially propagating fronts were shown to emerge in S gaps betwe...

Formation of stationary periodic patterns is paramount to many chemical, biological, physical, and ecological media. One of the most subtle mechanisms was suggested by Turing, who highlighted the applicability of isotropic reaction-diffusion dynamics with at least two diffusing fields. However, on finite domains with the presence of a symmetry brea...

A continuous process for nitrate and nitrite abatement from drinking water by catalytic hydrogenation has been developed in our lab. We describe the experimental process development procedure, and support it with semiempirical quantum chemical methods. Comparisons of activated carbon (ACC) and silica glass fiber (GFC) cloths as supports for mono‐ a...

Quantum effects on the rate constant and on the activation energy of the water dissociation reaction on (111) metal surfaces (Pt, Cu, Ru, and Rh) are described using an approach based on the approximate construction of an adiabatic potential energy surface (APES). Information about adsorption characteristics of the reactant and products is required...

A distinct propagation of solitary waves in the presence of autocatalysis, diffusion, and symmetry-breaking (differential) advection, is being studied. These pulses emerge at lower reaction rates of the autocatalytic activator, i.e., when the advective flow overcomes the fast excitation and induces a fluid type "drifting" behavior, making the pheno...

Loop reactors may compete with other heat recuperating technologies, like reverse-flow reactors, for catalytic abatement of low-concentration volatile organic compounds (VOC). Their main drawback, the narrow domain of operating parameters, can be resolved with a proper control system.The main goal of this research is to extend the optimal loop-reac...

Hydrogen generation by methane steam reforming in a thermally coupled membrane reformer−combustor has been experimentally studied. The concentric three-compartment reactor indirectly couples methane steam reforming with catalytic methane combustion and with a Pd−Ag membrane, to provide extrapure hydrogen. The reactor can be independently operated a...

We derive approximate relations for the propagation velocity and the maximal temperature rise of an “ideal” 1-D front in a pseudo-homogeneous packed bed reactor (PBR) model with a first order activated kinetics, accounting for a finite mass Peclet number (PeC). These relations are compared with known approximations for PeC→∞ and are verified by dir...

Pattern formation mechanisms of a reaction-diffusion-advection system, with one diffusivity, differential advection, and (Robin) boundary conditions of Danckwerts type, are being studied. Pattern selection requires mapping the domains of coexistence and stability of propagating or stationary nonuniform solutions, which for the general case of far f...

a b s t r a c t A novel concept for hydrogen generation by methane steam reforming in a thermally coupled catalytic fixed bed membrane reformer is experimentally demonstrated. The reactor, built from three concentric compartments, indirectly couples the endothermic methane steam reforming with the exothermic methane oxidation, while hydrogen is sep...

We present a theoretical study of nonlinear pattern selection mechanisms in a model of bounded reaction-diffusion-advection system. The model describes the activator-inhibitor type dynamics of a membrane reactor characterized by a differential advection and a single diffusion; the latter excludes any finite wave number instability in the absence of...

We use molecular mechanics universal force field parameters to calculate single- and multicomponent adsorption of phenol, para-bromophenol, and m-cresol from the gas or liquid phase on activated carbon (AC). The carbon pores are modeled by shallow carbon nanotubes of various pore diameters. The effect of pore length is studied for the case of pheno...

The kinetic and thermodynamic characteristics of oxygen penetration of palladium (111) surface are studied using the DFT cluster method. The activation energy and the energy difference between the adsorbed and subsurface states of oxygen atom as well as the corresponding frequency and geometrical characteristics are computed from the minimum energy...

We consider the stabilization of a rotating pulse in a system of connected chemical reactors that are organized in a loop with periodic switching of the feed between units. Such a solution has been shown to exist in a narrow domain of switching velocities (unit length/switching time). We use the switch velocity as control parameter and design it to...

The loop reactor, in the form composed of several units, with feed and exit ports switching, is investigated for a reversible exothermic reaction like the synthesis of methanol. Unlike applications of VOC combustion, which have been extensively investigated and experimentally tested, the maximal temperature here is limited by equilibrium conditions...

Pd–Cu catalysts supported on activated carbon cloth (Pd–Cu/ACC), prepared by selective catalytic deposition, showed a high activity (92% conversion) and selectivity (ca 93%) in the liquid phase hydrogenation of nitrates to nitrogen. From this study, first knowledge on the surface composition of a family of Cu–2wt%Pd/AC bimetallic catalysts and thei...

Composites are often used to obtain enhanced material properties, including improved mechanical performance, enhanced conductivity, increased transport and other properties. Recent advances in carbon nanotube (CNT) composite porous materials suggest that CNTs may offer a greater advantage than conventional fillers, not only due to their extraordina...

We consider the stabilization of a rotating temperature pulse moving in a continuous asymptotic model of many connected chemical reactors organized in a loop with continuously switching of the feed point synchronously with the motion of the pulse solution. We use the switch velocity as control parameter and design it to follow the pulse: the switch...

1. Introduction. Predicting hot zones in catalytic reactors is the focal point of design criteria aimed to avoid severe safety hazards. Thermal fronts are known to exist in such reactors and some experiments indicate that they may undergo symmetry breaking in the transversal direction under certain conditions. Note, that the linear stability analys...

This is the first experimental show of the loop reactor concept for catalytic oxidation of low-concentration volatile organic compounds (VOC). The loop reactor is an auto-thermal system of N units organized in a loop with periodic switching of the feed and exit ports (see Fig. 1). Numerical simulations (Barrsei et al. 1999) demonstrated this concep...

Hydrogen production by autothermal methane steam reforming in a catalytic fixed bed membrane reactor has been analyzed and simulated. The two-compartment reactor indirectly couples the endothermic steam reforming with methane oxidation, while hydrogen is separated by a permselective Pd membrane. Simulations of the reactor, using published kinetics,...

A loop reactor (LR) is an N-unit system composed of a loop with gradually shifted inlet/outlet ports. This system was shown in our previous study [Sheintuch M., Nekhamkina O., 2005. The asymptotes of loop reactors. A.I.Ch.E. Journal 51, 224–234] to admit an asymptotic model for a loop of a fixed length with N→∞. Both the finite-unit and the asympto...

Spatiotemporal patterns reported to form in the cross sections of packed-bed reactors (PBRs) may pose severe safety hazard when present next to the reactor wall. Understanding what causes their formation and dynamic features is essential for the rational development of design and control strategies that circumvent their generation. We review the cu...

An analytical approach searching for the saddle point on a semiempirical adiabatic potential surface (SP-SE-APES) is proposed in order to study diffusion of adsorbed molecules on a metal surface. Three reaction coordinates are used to construct this potential surface: the perpendicular adsorption height z, the distance x between adsorption sites (t...

Induction of metabolite production is a common feature of many cultures obtained by recombinant DNA technology. Synthesis of a product in these cultures is triggered by a sharp change in environmental conditions or by autoinduction in which the cells, under conditions of growth limitation, produce a species that initiates the synthesis. If product...

This article is the first experimental demonstration of autothermal operation in an open loop reactor for catalytic abatement of low-concentration volatile organic compounds (VOC). The system under investigation, which comprises three reactors organized in a loop with automatic switching of the feed position, has been successfully operated for ethy...

CO adsorption and desorption rates and adsorption equilibrium coefficients are analyzed for the processes on the close-packed metal surfaces of ruthenium, iridium, palladium, rhodium, and platinum assuming the adsorption to be activationless and using mobile and immobile adsorption layer models. Parameters required for calculations of the CO adsorp...

We show that a moving-front solution in a cylindrical shell packed-bed catalyzing a first-order activated reaction may bifurcate into transversal patterns when PeC/PeT<ΔTad/ΔTm, i.e. when the ratio of the mass to heat Pe numbers is smaller than the ratio of the adiabatic to maximal temperature rises. This coincides with the previous condition of tr...

A loop reactor (LR), composed as an N-unit loop with step-wise shifted inlet and outlet ports, is one of suggested technological solutions for low-concentration volatile organic compounds (VOC) combustion. Such a scheme ensures a sufficiently high temperature with autothermal behavior and nearly uniform catalytic utilization. The main drawback of t...

This work analyses the possible axial- and transversal thermal spatio-temporal patterns that may emerge in a two-dimensional thin annular catalytic bed model using a detailed micro-kinetic model for CO oxidation. This work is motivated by experimental IR-imaging observations made with a cylindrical catalytic surface impregnated with Pd. Stationary,...

An approximate analytical approach is suggested to calculate kinetic parameters for the catalytic oxidation of carbon monoxide on the (111) surfaces of transition metals of platinum, palladium, iridium, rhodium, and nickel. The origin of the activation barriers is discussed in terms of the decomposition analysis. Tunnel effect along the reaction co...

The present work extends our recently published study [Phys. Rev. E 73, 066224 (2006)] on a mechanism of pattern formation in excitable media due to inhomogeneous boundary conditions (BC). To that end, we analyze a pair of coupled excitable and oscillatory cells, a distributed FitzHugh Nagumo model, and a distributed five-variable model that descri...

We study diffusion through disordered porous structures, where the size of the diffusing particle is of the order of the pore diameter, and focus on the effect of particle–wall interactions. Such ‘configurational diffusion’ is important in catalysis, separation, and membrane technology, yet it is still poorly understood. We consider three types of...

This paper predicts the evolution of nanopores during anodic oxidation of aluminum. The theory is based on approximate nonlinear evolution equations of the interfaces, which reproduce all the observed patterns, and using them for stability analysis. The pore structure in the early stages is described by the Damped Kuramoto–Sivashinsky (DKS) equatio...

The adiabatic and nonadiabatic formalisms developed for calculations of the X2 molecule dissociative adsorption on metal surfaces are reviewed. The adiabatic formalism is extended here to account for the tunnel effect along the reaction coordinate. This approach is applied for calculating the activation energies, and rate constants associated with...

The stabilization of planar stationary fronts solutions in a two-dimensional rectangular or cylinder domain, in which a diffusion–convection–reaction process occurs, is studied by reducing the original two-variable PDEs model to an approximate one-dimensional model that describes the behavior of the front line. We consider the control strategy base...

This paper proposes a new approach for stabilizing a homogeneous solution in reaction–convection–diffusion system with oscillatory kinetics, in which moving or stationary patterns emerge in the absence of control. Specifically, we aim to suppress patterns by using a spatially weighted finite-dimensional feedback control that assures stability of th...