Dispersion of mass is a measure of the deviation of transportation of fluid in a reactor
from ideal reactor behavior (perfect mixing or plug flow) caused by the combined effects of
diffusion, convection and migration.
Axial dispersion is always undesirable because it reduces the driving force of the reaction
and therefore causes a lower level of conversion. On the other hand, transverse dispersion is
often a desirable feature since good transverse mixing will reduce the transverse concentration
and temperature gradients and hence improve the selectivity of a thermochemical reactor.
Transverse dispersion of mass is of more importance in a three-dimensional flow-by
electrochemical reactor than that in a thermochemical reactor because the potential drop is in the
transverse direction and the reaction rate and selectivity are determined by the potential as well as
concentration and temperature distributions. The transverse dispersion of mass is expected to
have a more profound effect on the performance of a 3D electrochemical reactor due to the
strong interaction among the concentration, temperature and potential distributions in the
transverse direction.
In the present work, the axial and transverse dispersion of mass were studied with a twodimensional
dispersion model in two types of rectangular packed bed: i) randomly packed glass
beads with the average bead diameter of 2 mm and a macroscopic bed porosity of 0.41; ii) a
representation of a 3D flow-by electrode - consisting of a bed of carbon felt with the carbon fibre
diameter of 20 urn and a macroscopic bed porosity of 0.95.
A tracer stimulation-response system was set up and axial and transverse dispersion of
In Blackfoot, DPs appear to take obligatory wide scope with respect to the universal quantifier
while bare nouns take obligatory narrow scope with respect to the universal quantifier. I propose that the
difference in scope-taking properties of Blackfoot nominals is a consequence of their syntactic position. I
propose that over argument DPs are adjoined to the clause whereas bare nouns are base generated in an
argument position. I suggest that the scope properties fall out from this distinction in the syntax.
The Blackfoot universal quantifier, ohkan-, is a preverb. That is, ohkan- occurs as a part of the
verb stem preceding the verb root itself. I propose that ohkan- is head of its own QP which takes the VP
as its complement. I follow Sportiche (1998) in categorizing ohkan- as a stranded quantifier since it is
base generated external to VP.
Bare nouns, since they are generated within VP, are structurally inferior to ohkan-, since they are
within its c-command domain. The adjoined DPs, however, are structurally superior to ohkan-, since they
are adjoined to the clause. I propose that the structural superiority of DPs translates to their obligatory
wide scope. Conversely, the structural inferiority of bare nouns translates to their obligatory narrow
scope.
Blackfoot is a relatively understudied Algonquian language spoken in Southern Alberta and
Northern Montana. The Blackfoot data presented in this work come primarily from my own work with
two Blackfoot speakers. Both of my language consultants hail from Southern Alberta speak and the Blood
dialect of Blackfoot.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/11282 |
| Date | 05 1900 |
| Creators | Glougie, Jennifer R. S. |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
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