Factors affecting broadband acoustic emission measurements of a heterogeneous reaction

The Analyst ◽  
2006 ◽  
Vol 131 (2) ◽  
pp. 323-330 ◽  
Author(s):  
Alison Nordon ◽  
Yvonne Carella ◽  
Anthony Gachagan ◽  
David Littlejohn ◽  
Gordon Hayward
2018 ◽  
Vol 140 (9) ◽  
Author(s):  
A. Rakhshi ◽  
T. Wiltowski

A kinetics assessment of the quasi-global homogeneous and heterogeneous reaction mechanisms is carried out for entrained flow coal gasification modeling. Accurate closure of the chemical source term in gasification modeling necessitates a detailed study of turbulence-chemistry interaction. Toward this end, a time-scale analysis of the homogeneous reactions is discussed using eigenvalue analysis of the reaction rate Jacobian matrix. A singular value decomposition (SVD) of the stoichiometric reaction matrix is performed to assess the behavior of the homogeneous reactions in a reduced species vector space. The significant factors affecting the heterogeneous char reactions are assessed, and the relative importance of bulk diffusion and inherent char kinetics is analyzed in a gasifier. The overall study is carried out using numerical and experimental results of an actual pilot scale gasifier.


The Analyst ◽  
2004 ◽  
Vol 129 (5) ◽  
pp. 463 ◽  
Author(s):  
Alison Nordon ◽  
Ruth J. H. Waddell ◽  
Luke J. Bellamy ◽  
Anthony Gachagan ◽  
Douglas McNab ◽  
...  

Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.


Author(s):  
Christine M. Dannels ◽  
Christopher Viney

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.


1990 ◽  
Vol 54 (11) ◽  
pp. 638-643 ◽  
Author(s):  
PC Damiano ◽  
ER Brown ◽  
JD Johnson ◽  
JP Scheetz

Sign in / Sign up

Export Citation Format

Share Document