The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Robert M. Ziff - One of the best experts on this subject based on the ideXlab platform.
-
Dynamic behavior of the monomer–monomer surface Reaction Model with adsorbate interactions
The Journal of Chemical Physics, 1997Co-Authors: Christopher A. Voigt, Robert M. ZiffAbstract:The monomer–monomer surface Reaction Model with an adsorbate interaction term is studied. An epidemic analysis of the poisoning times (tp) for small square lattices as a function of lattice edge length L and interaction strength α at the point of equal adsorption rates yields a dynamic scaling relation which describes the crossover between log-power-law and exponential behavior in L, and is able to fit the entire dependence of tp upon α and L. The phase transition is further explored by varying adsorption rates and is found to follow second-order kinetics. A mean-field approximation is introduced as a comparison for the numerical results.
-
Boundary effects in a surface Reaction Model for CO oxidation
The Journal of Chemical Physics, 1993Co-Authors: Benjamin J. Brosilow, Erdagon Gulari, Robert M. ZiffAbstract:The surface Reaction Model of Ziff, Gulari, and Barshad (ZGB) is investigated on finite systems with ‘‘hard’’ oxygen boundary conditions. The rate of production of CO2 is calculated as a function of y and system size. When the rate of CO adsorption y is above the first‐order transition value y2, the reactive region is found to extend into the system a distance ξ which scales as (y−y2)−0.40 when y→y2.
Kenji Kiyama - One of the best experts on this subject based on the ideXlab platform.
-
a reduced nox Reaction Model for pulverized coal combustion under fuel rich conditions
Fuel, 2002Co-Authors: Masayuki Taniguchi, Kenji Yamamoto, Hironobu Kobayashi, Kenji KiyamaAbstract:Abstract A reduced NO x Reaction Model was developed for analysis of industrial pulverized coal firing boilers. The Model was developed from experiments of laminar premixed combustion under a variety of stoichiometric ratios, burning temperatures, coal ranks (from sub-bituminous coal to anthracite) and particle diameters. Calculations agreed with experimental results for NO x and nitrogen species (NH 3 and HCN), if the Model assumed that the hydrocarbon radicals were formed not only from pyrolysis of volatile matter, but also from char oxidation and gasification. The presence of hydrogen in char at the final burnout stage supported this assumption. NO x reduction by hydrocarbon radicals was the most important Reaction in high temperature (>1500 K), fuel-rich, char combustion regions. NO x reduction from nitrogen species was sensitive to peak NO x concentration in volatile combustion regions, but NO x emission downstream had little influence from the peak NO x concentration. The heterogeneous Reaction between char and NO x was important for fuel-lean or low-temperature conditions.
Masayuki Taniguchi - One of the best experts on this subject based on the ideXlab platform.
-
a reduced nox Reaction Model for pulverized coal combustion under fuel rich conditions
Fuel, 2002Co-Authors: Masayuki Taniguchi, Kenji Yamamoto, Hironobu Kobayashi, Kenji KiyamaAbstract:Abstract A reduced NO x Reaction Model was developed for analysis of industrial pulverized coal firing boilers. The Model was developed from experiments of laminar premixed combustion under a variety of stoichiometric ratios, burning temperatures, coal ranks (from sub-bituminous coal to anthracite) and particle diameters. Calculations agreed with experimental results for NO x and nitrogen species (NH 3 and HCN), if the Model assumed that the hydrocarbon radicals were formed not only from pyrolysis of volatile matter, but also from char oxidation and gasification. The presence of hydrogen in char at the final burnout stage supported this assumption. NO x reduction by hydrocarbon radicals was the most important Reaction in high temperature (>1500 K), fuel-rich, char combustion regions. NO x reduction from nitrogen species was sensitive to peak NO x concentration in volatile combustion regions, but NO x emission downstream had little influence from the peak NO x concentration. The heterogeneous Reaction between char and NO x was important for fuel-lean or low-temperature conditions.
-
char surface Reaction Model for pulverized coal combustion
Transactions of the Japan Society of Mechanical Engineers. B, 1999Co-Authors: Kenji Yamamoto, Hisayuki Orita, Masayuki Taniguchi, Hironobu KobayashiAbstract:Experimental and analytical study was performed for surface Reaction Model that was used for numerical simulation of pulverized coal firing boiler. Combustion efficiency in downstream of premixed flames was examined for a subbituminous coal, two bituminous coals and an anthracite. The influence of SR (stoichiometric ratio), combustion temperature, FR (fuel ratio) and initial particle diameter was examined. Reaction rates of oxidation and gasification, and surface area Model of coal char were examined by comparison between experimental and analytical results. The outer surface area was assumed not to be changed during devolatilization, but to be reduced by surface Reaction. Effective surface area for Reaction was assumed to be decreased when ash content in char was increased. By using this surface area Model, comparison of the predicted combustion efficiency with the experimental data showed good agreement for SR 0.5∼1.5. Reaction rates were decreased when FR of coal increased. The effect of coal type was significant for gasification Reaction. The activation energy of gasification was smaller than the previous study that was obtained without oxygen. The Reaction yield by gasification at SR 0.8 was about 10%, gasification was found to be important for numerical simulation of pulverized coal firing boiler.
Yoshihiro Sugiyama - One of the best experts on this subject based on the ideXlab platform.
-
consideration of switching mechanism of binary metal oxide resistive junctions using a thermal Reaction Model
Applied Physics Letters, 2007Co-Authors: Yoshihiro Sato, Masaki Aoki, Kentaro Kinoshita, Yoshihiro SugiyamaAbstract:The authors investigated the resistive switching of transition metal oxide (TMO) junctions by applying a short voltage pulse and found that the response time of the “reset” process was dependent on the resistance in the low resistive state. By using a thermal conductive equation to calculate the temperature of the filamentary conductive path in the TMO film, the temperature in the reset process was estimated to reach the same temperature grade in each reset. On this basis, the previous experimental relation is well explained by assuming a general thermal chemical Reaction Model for the reset process.
Hironobu Kobayashi - One of the best experts on this subject based on the ideXlab platform.
-
a reduced nox Reaction Model for pulverized coal combustion under fuel rich conditions
Fuel, 2002Co-Authors: Masayuki Taniguchi, Kenji Yamamoto, Hironobu Kobayashi, Kenji KiyamaAbstract:Abstract A reduced NO x Reaction Model was developed for analysis of industrial pulverized coal firing boilers. The Model was developed from experiments of laminar premixed combustion under a variety of stoichiometric ratios, burning temperatures, coal ranks (from sub-bituminous coal to anthracite) and particle diameters. Calculations agreed with experimental results for NO x and nitrogen species (NH 3 and HCN), if the Model assumed that the hydrocarbon radicals were formed not only from pyrolysis of volatile matter, but also from char oxidation and gasification. The presence of hydrogen in char at the final burnout stage supported this assumption. NO x reduction by hydrocarbon radicals was the most important Reaction in high temperature (>1500 K), fuel-rich, char combustion regions. NO x reduction from nitrogen species was sensitive to peak NO x concentration in volatile combustion regions, but NO x emission downstream had little influence from the peak NO x concentration. The heterogeneous Reaction between char and NO x was important for fuel-lean or low-temperature conditions.
-
char surface Reaction Model for pulverized coal combustion
Transactions of the Japan Society of Mechanical Engineers. B, 1999Co-Authors: Kenji Yamamoto, Hisayuki Orita, Masayuki Taniguchi, Hironobu KobayashiAbstract:Experimental and analytical study was performed for surface Reaction Model that was used for numerical simulation of pulverized coal firing boiler. Combustion efficiency in downstream of premixed flames was examined for a subbituminous coal, two bituminous coals and an anthracite. The influence of SR (stoichiometric ratio), combustion temperature, FR (fuel ratio) and initial particle diameter was examined. Reaction rates of oxidation and gasification, and surface area Model of coal char were examined by comparison between experimental and analytical results. The outer surface area was assumed not to be changed during devolatilization, but to be reduced by surface Reaction. Effective surface area for Reaction was assumed to be decreased when ash content in char was increased. By using this surface area Model, comparison of the predicted combustion efficiency with the experimental data showed good agreement for SR 0.5∼1.5. Reaction rates were decreased when FR of coal increased. The effect of coal type was significant for gasification Reaction. The activation energy of gasification was smaller than the previous study that was obtained without oxygen. The Reaction yield by gasification at SR 0.8 was about 10%, gasification was found to be important for numerical simulation of pulverized coal firing boiler.
