Classification and Use of Terms for Amplification and Related Reactions

1999 ◽  
Vol 71 (7) ◽  
pp. 1331-1335
Author(s):  
D. T. Burns ◽  
A. Townshend
Keyword(s):  
Classification Scheme ◽  
Systematic Classification

A systematic classification scheme is given for the various types of amplification and related reactions currently available. The report extends and refines earlier IUPAC recommendations (Pure Appl. Chem.54 (1982), 2553-2556) to include non-multiplication reactions.

scholarly journals Kinetic regimes and limiting cases of gas uptake and heterogeneous reactions in atmospheric aerosols and clouds: a general classification scheme

2013 ◽  
Vol 13 (1) ◽  
pp. 983-1044
Author(s):  
T. Berkemeier ◽  
A. J. Huisman ◽  
M. Ammann ◽  
M. Shiraiwa ◽  
T. Koop ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Classification Scheme ◽  
Transport Processes ◽  
Heterogeneous Reactions ◽  
Diffusion Reaction ◽  
Systematic Classification ◽  
Gas Uptake ◽  
Reaction Systems

Abstract. Heterogeneous reactions are important to atmospheric chemistry and are therefore an area of intense research. In multiphase systems such as aerosols and clouds, chemical reactions are usually strongly coupled to a complex sequence of mass transport processes and results are often not easy to interpret. Here we present a systematic classification scheme for gas uptake by aerosol or cloud particles which distinguishes two major regimes: a reaction-diffusion regime and a mass-transfer regime. Each of these regimes includes four distinct limiting cases, characterized by a dominant reaction location (surface or bulk) and a single rate-limiting process: chemical reaction, bulk diffusion, gas-phase diffusion or mass accommodation. The conceptual framework enables efficient comparison of different studies and reaction systems, going beyond the scope of previous classification schemes by explicitly resolving interfacial transport processes and surface reactions limited by mass transfer from the gas phase. The use of kinetic multi-layer models instead of resistor model approaches increases the flexibility and enables a broader treatment of the subject, including cases which do not fit into the strict limiting cases typical of most resistor model formulations. The relative importance of different kinetic parameters such as diffusion, reaction rate and accommodation coefficients in this system is evaluated by a quantitative global sensitivity analysis. We outline the characteristic features of each limiting case and discuss the potential relevance of different regimes and limiting cases for various reaction systems. In particular, the classification scheme is applied to three different data sets for the benchmark system of oleic acid reacting with ozone. In light of these results, future directions of research needed to elucidate the multiphase chemical kinetics in this and other reaction systems are discussed.

Pillared Clays and Pillared Layered Solids

1999 ◽  
Vol 71 (12) ◽  
pp. 2367-2371 ◽  
Author(s):  
R. A. Schoonheydt ◽  
T. Pinnavaia ◽  
Gerhard Lagaly ◽  
Nick Gangas
Keyword(s):  
Classification Scheme ◽  
Pillared Clays ◽  
Inorganic Compound ◽  
Layered Compound ◽  
Systematic Classification ◽  
Characterization Methods ◽  
Interlayer Region ◽  
Layered Solid

Pillaring is a commonly used procedure to transform a layered crystalline inorganic compound into a material with microporosity and mesoporosity. First, the terms "layered compound, pillaring, pillaring agent and interlayer region" are defined, and then the term pillared layered solid or pillared compound. In the second part, the standard characterization methods and procedures and a systematic classification scheme are proposed.

scholarly journals Kinetic regimes and limiting cases of gas uptake and heterogeneous reactions in atmospheric aerosols and clouds: a general classification scheme

2013 ◽  
Vol 13 (14) ◽  
pp. 6663-6686 ◽  
Author(s):  
T. Berkemeier ◽  
A. J. Huisman ◽  
M. Ammann ◽  
M. Shiraiwa ◽  
T. Koop ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Gas Phase ◽  
Atmospheric Chemistry ◽  
Classification Scheme ◽  
Transport Processes ◽  
Heterogeneous Reactions ◽  
Diffusion Reaction ◽  
Systematic Classification ◽  
Gas Uptake ◽  
Reaction Systems

Abstract. Heterogeneous reactions are important to atmospheric chemistry and are therefore an area of intense research. In multiphase systems such as aerosols and clouds, chemical reactions are usually strongly coupled to a complex sequence of mass transport processes and results are often not easy to interpret. Here we present a systematic classification scheme for gas uptake by aerosol or cloud particles which distinguishes two major regimes: a reaction-diffusion regime and a mass transfer regime. Each of these regimes includes four distinct limiting cases, characterised by a dominant reaction location (surface or bulk) and a single rate-limiting process: chemical reaction, bulk diffusion, gas-phase diffusion or mass accommodation. The conceptual framework enables efficient comparison of different studies and reaction systems, going beyond the scope of previous classification schemes by explicitly resolving interfacial transport processes and surface reactions limited by mass transfer from the gas phase. The use of kinetic multi-layer models instead of resistor model approaches increases the flexibility and enables a broader treatment of the subject, including cases which do not fit into the strict limiting cases typical of most resistor model formulations. The relative importance of different kinetic parameters such as diffusion, reaction rate and accommodation coefficients in this system is evaluated by a quantitative global sensitivity analysis. We outline the characteristic features of each limiting case and discuss the potential relevance of different regimes and limiting cases for various reaction systems. In particular, the classification scheme is applied to three different datasets for the benchmark system of oleic acid reacting with ozone in order to demonstrate utility and highlight potential issues. In light of these results, future directions of research needed to elucidate the multiphase chemical kinetics in this and other reaction systems are discussed.

scholarly journals Nomenclature of structural and compositional characteristics of ordered microporous and mesoporous materials with inorganic hosts(IUPAC Recommendations 2001)

2001 ◽  
Vol 73 (2) ◽  
pp. 381-394 ◽  
Author(s):  
L. B. McCusker ◽  
F. Liebau ◽  
G. Engelhardt
Keyword(s):  
Chemical Composition ◽  
Mesoporous Materials ◽  
Classification Scheme ◽  
Inorganic Materials ◽  
Crystal Chemical ◽  
Chemical Formula ◽  
Crystal Chemical Formula ◽  
Pore System ◽  
Systematic Classification ◽  
Guest Species

A system of terms applicable to ordered microporous and mesoporous materials is proposed, and rules for writing a standardized crystal chemical formula for such materials are presented. The recommendations are based both on common usage and on a systematic classification scheme. The nomenclature has been developed to encompass all inorganic materials with ordered, accessible pores with free diameters of less than 50 nm. The crystal chemical formula describes the chemical composition of both the guest species and the host, the structure of the host, the structure of the pore system, and the symmetry of the material. This formula can be simplified or expanded to suit the user's requirements.

Statistical analysis of classification

1966 ◽  
Vol 24 ◽  
pp. 188-189
Author(s):  
T. J. Deeming
Keyword(s):  
Multivariate Analysis ◽  
Statistical Analysis ◽  
Classification Scheme ◽  
Analytical Procedure ◽  
Narrow Band ◽  
Scientific Research ◽  
Maximum Amount ◽  
Amount Of Information

If we make a set of measurements, such as narrow-band or multicolour photo-electric measurements, which are designed to improve a scheme of classification, and in particular if they are designed to extend the number of dimensions of classification, i.e. the number of classification parameters, then some important problems of analytical procedure arise. First, it is important not to reproduce the errors of the classification scheme which we are trying to improve. Second, when trying to extend the number of dimensions of classification we have little or nothing with which to test the validity of the new parameters.Problems similar to these have occurred in other areas of scientific research (notably psychology and education) and the branch of Statistics called Multivariate Analysis has been developed to deal with them. The techniques of this subject are largely unknown to astronomers, but, if carefully applied, they should at the very least ensure that the astronomer gets the maximum amount of information out of his data and does not waste his time looking for information which is not there. More optimistically, these techniques are potentially capable of indicating the number of classification parameters necessary and giving specific formulas for computing them, as well as pinpointing those particular measurements which are most crucial for determining the classification parameters.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

A Perturbation Theory for the Population of Atomic Energy Levels in Non-Lte Plasmas

1988 ◽  
Vol 102 ◽  
pp. 343-347
Author(s):  
M. Klapisch
Keyword(s):  
Perturbation Theory ◽  
Small Parameter ◽  
Classification Scheme ◽  
Sum Rules ◽  
Energy Levels ◽  
Natural Classification ◽  
Quantum Numbers ◽  
Formal Expansion ◽  
Atomic Energy Levels ◽  
As Effects

AbstractA formal expansion of the CRM in powers of a small parameter is presented. The terms of the expansion are products of matrices. Inverses are interpreted as effects of cascades.It will be shown that this allows for the separation of the different contributions to the populations, thus providing a natural classification scheme for processes involving atoms in plasmas. Sum rules can be formulated, allowing the population of the levels, in some simple cases, to be related in a transparent way to the quantum numbers.

The value of Electron Microscope studies of imperfect natural diamonds

1990 ◽  
Vol 48 (4) ◽  
pp. 194-195
Author(s):  
J C Walmsley ◽  
A R Lang
Keyword(s):  
Electron Microscope ◽  
Classification Scheme ◽  
Natural Diamond ◽  
Sudden Change ◽  
Growth Conditions ◽  
Diamond Growth ◽  
Major Constituent ◽  
Natural Diamonds ◽  
Type Ia ◽  
Platelet Defects

Interest in the defects and impurities in natural diamond, which are found in even the most perfect stone, is driven by the fact that diamond growth occurs at a depth of over 120Km. They display characteristics associated with their origin and their journey through the mantle to the surface of the Earth. An optical classification scheme for diamond exists based largely on the presence and segregation of nitrogen. For example type Ia, which includes 98% of all natural diamonds, contain nitrogen aggregated into small non-paramagnetic clusters and usually contain sub-micrometre platelet defects on {100} planes. Numerous transmission electron microscope (TEM) studies of these platelets and associated features have been made e.g. . Some diamonds, however, contain imperfections and impurities that place them outside this main classification scheme. Two such types are described.First, coated-diamonds which possess gem quality cores enclosed by a rind that is rich in submicrometre sized mineral inclusions. The transition from core to coat is quite sharp indicating a sudden change in growth conditions, Figure 1. As part of a TEM study of the inclusions apatite has been identified as a major constituent of the impurity present in many inclusion cavities, Figure 2.

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