2,424 research outputs found
Phase Equilibria for Quaternary Mixtures in Esterification Reaction Systems
This paper examines the effect of the simultaneous chemical and phase equilibrium on the conceptual design of reactive distillation processes. Esterification of acetic acid with methanol, ethanol and butanol are examined. Using commercial software, azeotropic points, residue curve maps and distillation line diagrams having been calculated. The analyzed systems have showed different behavior when phase equilibrium parameters and chemical equilibrium constants are changed. The methyl acetate system does not change the topological features of residue curve maps and distillation line diagrams. The ethyl acetate system and the butyl acetate system change the topological features of the graphs when different chemical equilibrium constants are used.Fil: Campanella, Enrique Angel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de Desarrollo TecnolĂłgico para la Industria QuĂmica. Universidad Nacional del Litoral. Instituto de Desarrollo TecnolĂłgico para la Industria QuĂmica; ArgentinaFil: Mandagaran, Beatriz Adriana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de Desarrollo TecnolĂłgico para la Industria QuĂmica. Universidad Nacional del Litoral. Instituto de Desarrollo TecnolĂłgico para la Industria QuĂmica; Argentin
Distribution Coefficient Calculation in Ternary Liquid-Liquid Systems
A good description of liquid-liquid equilibrium is important to design extraction separation processes. Equilibrium data are normally needed as distribution coefficients for each individual component. In this paper we have combined activity coefficient models with Hand?s equation for tie lines to calculate distribution coefficients in ternary systems. The proposed method gives betterdistribution coefficients than those calculated using only activity coefficient models. Besides, the proposed method could be employed to extrapolate experimental information when liquid-liquid equilibrium data are few.Fil: Mandagaran, Beatriz Adriana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de Desarrollo TecnolĂłgico para la Industria QuĂmica. Universidad Nacional del Litoral. Instituto de Desarrollo TecnolĂłgico para la Industria QuĂmica; ArgentinaFil: Campanella, Enrique Angel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de Desarrollo TecnolĂłgico para la Industria QuĂmica. Universidad Nacional del Litoral. Instituto de Desarrollo TecnolĂłgico para la Industria QuĂmica; Argentin
Quasi-Ballistic Electron Transport in Random Superlattices
We theoretically study electron transport in disordered, quantum-well based,
semiconductor superlattices with structural short-range correlations. Our
system consists of equal width square barriers and quantum wells with two
different thicknesses. The two kinds of quantum wells are randomly distributed
along the growth direction. Structural correlations are introduced by adding
the constraint that one of the wells always appears in pairs. We show that such
correlated disordered superlattices exhibit a strong enhancement of their dc
conductance as compared to usual random ones, giving rise to quasi-ballistic
electron transport. Our predictions can be used to demonstrate experimentally
that structural correlations inhibit the localization effects of disorder. We
specifically describe the way superlattices should be built and experiments
should be carried out for that purpose.Comment: REVTeX 3.0, 7 pages, 4 figures on request from FD-A
([email protected]). Submitted to Physical Review B. Preprint
MA/UC3M/12/199
Absence of localization and large dc conductance in random superlattices with correlated disorder
We study how the influence of structural correlations in disordered systems
manifests itself in experimentally measurable magnitudes, focusing on dc
conductance of semiconductor superlattices with general potential profiles. We
show that the existence of bands of extended states in these structures gives
rise to very noticeable peaks in the finite temperature dc conductance as the
chemical potential is moved through the bands or as the temperature is
increased from zero. On the basis of these results we discuss how dc
conductance measurements can provide information on the location and width of
the bands of extended states. Our predictions can be used to demonstrate
experimentally that structural correlations inhibit the localization effects of
disorder.Comment: REVTeX 3.0, 14 pages, 11 figures available on request from ED
([email protected]). Submitted to Phys Rev B. MA/UC3M/06/9
Excitation decay in one-dimensional disordered systems with paired traps
Incoherent transport of excitations in one-dimensional disordered lattices
with pairs of traps placed at random is studied by numerically solving the
corresponding master equation. Results are compared to the case of lattices
with the same concentration of unpaired traps, and it is found that pairing of
traps causes a slowdown of the decay rate of both the mean square displacement
and the survival probability of excitations. We suggest that this result is due
to the presence of larger trap-free segments in the lattices with paired
disorder, which implies that pairing of traps causes less disruption on the
dynamics of excitations. In the conclusion we discuss the implications of our
work, placing it in a more general context.Comment: REVTeX 3.0, 10 pages, 7 figures available on request from FD-A
([email protected]), Universidad Carlos III preprint MA/UC3M/08/9
Incoherent Exciton Trapping in Self-Similar Aperiodic Lattices
Incoherent exciton dynamics in one-dimensional perfect lattices with traps at
sites arranged according to aperiodic deterministic sequences is studied. We
focus our attention on Thue-Morse and Fibonacci systems as canonical examples
of self-similar aperiodic systems. Excitons progressively extend over the
lattice on increasing time and, in this sense, they act as a probe of the
particular arrangements of traps in each system considered. The analysis of the
characteristic features of their time decay indicates that exciton dynamics in
self-similar aperiodic arrangements of traps is quite close to that observed in
periodic ones, but differs significatively from that corresponding to random
lattices. We also report on characteristic features of exciton motion
suggesting that Fibonacci and Thue-Morse orderings might be clearly observed by
appropriate experimental measurements. In the conclusions we comment on the
implications of our work on the way towards a unified theory of the orderings
of matter.Comment: REVTeX 3.0, 10 pages, 2 figures on request from FD-A
([email protected]). Submitted to Phys Rev B. MA/UC3M/11/9
Monetary Policy Targeting in Argentina and Canada in the 1990s: A Comparison, Some Contrasts, and a Tentative Evaluation
There are two generally accepted ways of plotting the aggregate demand (AD) and aggregate supply (AS) curves in the goods market. One puts the price level on the vertical axis (the P - y approach); the other plots the real interest rate on the vertical axis (the r - y approach). This paper develops the theoretical connections between these two approaches that permit one to tell a coherent dynamic story with the AD-AS model and also explores the conditions under which one approach or the other yields greater insight into the working of the model.Monetary Policy; Monetary; Policy
Accuracy Assessment of a Drone Mapping System
The practical application of drones is dependent on the accuracy of their sensors. This study was conducted to statistically compare the California Department of Transportation’s (Caltrans) existing data with the newly acquired data created with a DJI Phantom 4 Pro. To better serve California, Caltrans requested this study to assess the use of drones in highway planning and design. Caltrans historically outsourced its aerial imagery acquisition to third party contractors. This process takes months for the imagery to be delivered, is expensive, and prone to delays. Determining the accuracy of drone mapping would allow the organization to have an in-house team dedicated to creating new data with a turnaround time of hours rather than months if the accuracy meets industry standards
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