A unified model for top fired methane steam reformers using three-dimensional zonal analysis

Recently, the HST imaging observations have revealed that the central arc second region in NGC 1068 has a clumpy structure (Macchetto et al., 1994) and the HST UV imaging polarimetry has revealed the centrosymmetric pattern of the position angles of polarization (Capetti et al., 1995), which indicates that the medium in this region is actually scattering the radiation from a small source, in accordance with the unified model of active galactic nuclei (Antonucci & Miller, 1985).

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Implicit-Explicit Formulations of a Three-Dimensional Nonhydrostatic Unified Model of the Atmosphere (NUMA)

SIAM Journal on Scientific Computing ◽

10.1137/120876034 ◽

2013 ◽

Vol 35 (5) ◽

pp. B1162-B1194 ◽

Cited By ~ 84

Author(s):

F. X. Giraldo ◽

J. F. Kelly ◽

E. M. Constantinescu

Keyword(s):

Three Dimensional ◽

Unified Model

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An Enhanced Sherwood Number to Model the Hydrogen Transport in Membrane Steam Reformers

Membranes ◽

10.3390/membranes11110805 ◽

2021 ◽

Vol 11 (11) ◽

pp. 805

Author(s):

Maria Anna Murmura ◽

Chiara Rocchetti ◽

Maria Cristina Annesini

Keyword(s):

Sherwood Number ◽

Gas Flow ◽

Operating Conditions ◽

Membrane Reactors ◽

Methane Steam Reforming ◽

Concentration Gradients ◽

Methane Steam ◽

Simplifying Assumptions ◽

1D Model ◽

Steam Reformers

It is well known that membrane reactors are inherently two-dimensional systems in which species concentrations vary as a consequence of both the reaction and permeation across the membrane, which occurs in the direction perpendicular to that of the main gas flow. Recently, an expression for an enhanced Sherwood number was developed to describe the hydrogen concentration gradients arising in methane steam-reforming membrane reactors as a consequence of the combined effect of hydrogen production, dispersion, and permeation. Here, the analysis is developed in further detail with the aim of (i) assessing the validity of the simplifying assumptions made when developing the 1D model and (ii) identifying the operating conditions under which it is possible to employ the 1D model with the enhanced Sherwood number.

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A UNIFIED MODEL AND METHODOLOGY FOR TEMPORAL OBJECT DATABASES

International Journal of Cooperative Information Systems ◽

10.1142/s0218215793000101 ◽

1993 ◽

Vol 02 (02) ◽

pp. 201-223 ◽

Cited By ~ 3

Author(s):

NIKI PISSINOU ◽

KIA MAKKI

Keyword(s):

Information Systems ◽

Geographic Information Systems ◽

Three Dimensional ◽

Geographic Information ◽

Unified Model ◽

Space Model ◽

Database Visualization ◽

Temporal Object ◽

Object Databases ◽

And Robotics

This paper identifies, explores and provides an approach to handling temporal information in object databases. It specifically involves the design and development of the Temporal Three Dimensional Information Space model that integrates time with objects. The model is based on a small number of simple temporal object constructs and provides a user with the basic primitives for temporal object definition, manipulation and retrieval. This research presents a step towards defining the concepts and techniques for incorporating time in object databases, and provides concrete experimental framework for demonstration thereof. Target Application environments include management and geographic information systems, database visualization and robotics.

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