Hexaaluminate catalysts for the partial oxidation of middle distillate fuels

Studies were conducted on active metals (i.e., Co, Fe and Ni) substituted into the lattice of hexaaluminate compounds to reform liquid hydrocarbon fuels into H2-rich synthesis gas for fuel cell applications. Both the concentration of active metals substituted into the lattice and the different mirror cations, (i.e., Ba, La and Sr) were investigated for their effect on the catalytic properties of the hexaaluminate compound. In these studies, n-tetradecane was used as a model middle distillate fuel. The synthesized catalysts were characterized by a series of techniques including: N2 BET surface area, powder XRD, TPR, H2 pulse chemisorption, bulk elemental analysis by ICP, and surface analysis by XPS.;The catalysts were shown to exhibit P63/mmc crystal symmetry which was indicative of the hexaaluminate structure. TPR experiments on the catalysts indicated that the substitution of cobalt, iron and nickel cations into the lattice stabilized their reducibility. The reduction temperature for the nickel series of catalysts correlated with the type of mirror cation substituted into the lattice. H2 pulse chemisorption performed on reduced nickel hexaaluminate catalysts confirmed that the number of active nickel sites that were reduced in the lattice was influenced by the mirror cation. XPS analysis of LaNi0.4Al11.6O19-delta , SrNi0.4Al11.6O19-delta and BaNi 0.4Al11.6O19-delta catalysts indicated that the variation in the nickel surface concentration of the oxide catalysts also correlated with the mirror cation.;The activity of the synthesized catalysts toward the partial oxidation of n-tetradecane was examined by temperature programmed reaction between 750 to 900°C. Iron substituted into the hexaaluminate lattice was shown to exhibit relatively poor catalytic activity and selectivity at all concentrations during the temperature programmed reaction with n-tetradecane. Cobalt substituted into the hexaaluminate lattice at concentrations of y ≤ 0.8 (LaCo yAl12-yO19-delta) exhibited equally poor catalytic activity and selectivity. However, the LaCoAl11O19-delta catalyst exhibited equilibrium CO and H2 yields.;The LaNiyAl12-yO19-delta (y = 0.2, 0.4, 0.8 and 1.0) series and the MINi0.4Al11.6 O19-delta (MI = Ba, La and Sr) series of catalysts possessed the greatest H2 and CO activity and selectivity over the temperature region examined. Both the LaNi0.2Al11.8O 19-delta and the BaNi0.4Al11.6O19-delta catalysts exhibited sharp increases in H2 yield at 850 and 875°C, respectively. The increase in H2 yield in this region corresponded to a decrease in CH4 yield indicating that the additional H2 produced was derived from CH4.;The role that the mirror cation produced on nickel substituted hexaaluminate stability during n-tetradecane isothermal partial oxidation was also examined. Nickel catalysts with Ba2+ and Sr2+ mirror cations exhibited greater stability during n-tetradecane partial oxidation than did the La3+ cation. The catalytic behavior induced by the mirror cation suggested that its influence on controlling carbon deposition was structural

Order Execution Quality in Equity Options Markets

In Part 1, we examine the effects of an order cancellation fee on limit order behavior and execution quality on the NASDAQ OMX PHLX. We find that the cancellation fee is effective in reducing the rate at which limit orders are submitted and subsequently deleted. Order volume declines, however, the remaining displayed orders appear to constitute more genuine liquidity, as the duration of canceled orders lengthens. The reduction in order cancellation activity is associated with lower effective spreads and higher order fill rates. We also find that differences in trading venues and option characteristics are important determinants of order cancellations in options markets. Overall, our results suggest that reducing excessive order cancellation activity may improve the quality of liquidity provision and, consequently, enhance order execution quality. In Part 2, we examine if the priority rules, such as price-time or pro-rata, which govern the order matching process on an exchange, affect limit order quality and transaction outcomes. Our multivariate tests show that the probability of execution is higher in the price-time model, while time-to-execution is significantly shorter in the pro-rata model. We also provide evidence that traders risk over-trading in the pro-rata model by submitting large order sizes to achieve a desire fill amount and then cancel the remaining contracts. In Part 3, we examine the impact of option quote stuffing and trading spikes on market quality. We find that quote stuffing and trading spikes in U.S. equity options are more frequently observed on exchanges using price-time priority, relative to exchanges using pro-rata priority. Our multivariate analysis shows that quote stuffing reduces the probability of execution and lengthens the time-to-execution on option orders. We also find that both quote stuffing and trading spikes are associated with transitory frictions in option order execution prices. In addition, we find that bid-ask spreads in the underlying securities increase, with a one-minute lag, around option quote stuffing episodes. Overall, our analysis provides evidence that quote stuffing and trade spikes reduce both liquidity and order execution quality in securities markets

Characterisation of microsatellites for Litoria nannotis (Amphibia : Hylidae), an endangered waterfall frog endemic to the Australian Wet Tropics

Litoria nannotis is an endangered waterfall frog from the wet tropics region in north Queensland that has suffered significant population declines due to the emerging fungal disease known as chytridiomycosis. The species has two deeply divergent lineages, and we used 454 shotgun sequencing of DNA extracted from one individual of the northern lineage to identify and design PCR primers for 576 microsatellite loci. Thirty markers were tested for amplification success and variability in a population sample from each lineage. Of these, 17 were found to be polymorphic in the northern lineage and 10 loci were polymorphic in the southern lineage. Numbers of alleles per locus ranged from 2 to 14 (mean = 6.47, s.d. = 4.02) for the northern lineage (17 polymorphic loci), and from 2 to 8 (mean = 5.40, s.d. = 2.55) in the southern lineage (10 polymorphic loci). Levels of heterozygosity were high in both lineages (northern meanHE = 0.63, s.d. = 0.21, range = 0.27–0.89; southern mean HE = 0.57, s.d. = 0.25, range = 0.18–0.81). These loci will be useful in understanding the genetic variation and connectivity amongst populations of this species recovering from mass population declines due to disease

Songbird organotypic culture as an in vitro model for interrogating sparse sequencing networks

Sparse sequences of neuronal activity are fundamental features of neural circuit computation; however, the underlying homeostatic mechanisms remain poorly understood. To approach these questions, we have developed a method for cellular-resolution imaging in organotypic cultures of the adult zebra finch brain, including portions of the intact song circuit. These in vitro networks can survive for weeks, and display mature neuron morphologies. Neurons within the organotypic slices exhibit a diversity of spontaneous and pharmacologically induced activity that can be easily monitored using the genetically encoded calcium indicator GCaMP6. In this study, we primarily focus on the classic song sequence generator HVC and the surrounding areas. We describe proof of concept experiments including physiological, optical, and pharmacological manipulation of these exposed networks. This method may allow the cellular rules underlying sparse, stereotyped neural sequencing to be examined with new degrees of experimental control

Finding and Mitigating Geographic Vulnerabilities in Mission Critical Multi-Layer Networks

Title from PDF of title page, viewed on June 20, 2016Dissertation advisor: Cory BeardVitaIncludes bibliographical references (pages 232-257)Thesis(Ph.D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2016In Air Traffic Control (ATC), communications outages may lead to immediate loss of communications or radar contact with aircraft. In the short term, there may be safety related issues as important services including power systems, ATC, or communications for first responders during a disaster may be out of service. Significant financial damage from airline delays and cancellations may occur in the long term. This highlights the different types of impact that may occur after a disaster or other geographic event. The question is How do we evaluate and improve the ability of a mission-critical network to perform its mission during geographically correlated failures? To answer this question, we consider several large and small networks, including a multi-layer ATC Service Oriented Architecture (SOA) network known as SWIM. This research presents a number of tools to analyze and mitigate both long and short term geographic vulnerabilities in mission critical networks. To provide context for the tools, a disaster planning approach is presented that focuses on Resiliency Evaluation, Provisioning Demands, Topology Design, and Mitigation of Vulnerabilities. In the Resilience Evaluation, we propose a novel metric known as the Network Impact Resilience (NIR) metric and a reduced state based algorithm to compute the NIR known as the Self-Pruning Network State Generation (SP-NSG) algorithm. These tools not only evaluate the resiliency of a network with a variety of possible network tests, but they also identify geographic vulnerabilities. Related to the Demand Provisioning and Mitigation of Vulnerabilities, we present methods that focus on provisioning in preparation for rerouting of demands immediately following an event based on Service Level Agreements (SLA) and fast rerouting of demands around geographic vulnerabilities using Multi-Topology Routing (MTR). The Topology Design area focuses on adding nodes to improve topologies to be more resistant to geographic vulnerabilities. Additionally, a set of network performance tools are proposed for use with mission critical networks that can model at least up to 2nd order network delay statistics. The first is an extension of the Queueing Network Analyzer (QNA) to model multi-layer networks (and specifically SOA networks). The second is a network decomposition tool based on Linear Algebraic Queueing Theory (LAQT). This is one of the first extensive uses of LAQT for network modeling. Benefits, results, and limitations of both methods are described.Introduction -- SWIM Network - Air traffic Control example -- Performance analysis of mission critical multi-layer networks -- Evaluation of geographically correlated failures in multi-layer networks -- Provisioning and restoral of mission critical services for disaster resilience -- Topology improvements to avoid high impact geographic events -- Routing of mission critical services during disasters -- Conclusions and future research -- Appendix A. Pub/Sub simulation model description -- Appendix B. ME Random Number Generatio

Combining a Dispersal Model with Network Theory to Assess Habitat Connectivity

Assessing the potential for threatened species to persist and spread within fragmented landscapes requires the identification of core areas that can sustain resident populations and dispersal corridors that can link these core areas with isolated patches of remnant habitat. We developed a set of GIS tools, simulation methods, and network analysis procedures to assess potential landscape connectivity for the Delmarva fox squirrel (DFS; Sciurus niger cinereus), an endangered species inhabiting forested areas on the Delmarva Peninsula, USA. Information on the DFS’s life history and dispersal characteristics, together with data on the composition and configuration of land cover on the peninsula, were used as input data for an individual-based model to simulate dispersal patterns of millions of squirrels. Simulation results were then assessed using methods from graph theory, which quantifies habitat attributes associated with local and global connectivity. Several bottlenecks to dispersal were identified that were not apparent from simple distance-based metrics, highlighting specific locations for landscape conservation, restoration, and/or squirrel translocations. Our approach links simulation models, network analysis, and available field data in an efficient and general manner, making these methods useful and appropriate for assessing the movement dynamics of threatened species within landscapes being altered by human and natural disturbances

Neighborhood context and financial strain as predictors of marital interaction and marital quality in African American couples

Demographic characteristics, family financial strain, neighborhood–level economic disadvantage, and state of residence were tested as predictors of observed warmth, hostility, and self–reported marital quality. Participants were 202 married African American couples who resided in a range of neighborhood contexts. Neighborhood–level economic disadvantage predicted lower warmth during marital interactions, as did residence in the rural south. Consistent with the family stress model (e.g., Conger & Elder, 1994), family financial strain predicted lower perceived marital quality. Unexpectedly, neighborhood–level economic disadvantage predicted higher marital quality. Social comparison processes and degree of exposure to racially based discrimination are considered as explanations for this unexpected result. The importance of context in relationship outcomes is highlighted

Existence and stability of hole solutions to complex Ginzburg-Landau equations

We consider the existence and stability of the hole, or dark soliton, solution to a Ginzburg-Landau perturbation of the defocusing nonlinear Schroedinger equation (NLS), and to the nearly real complex Ginzburg-Landau equation (CGL). By using dynamical systems techniques, it is shown that the dark soliton can persist as either a regular perturbation or a singular perturbation of that which exists for the NLS. When considering the stability of the soliton, a major difficulty which must be overcome is that eigenvalues may bifurcate out of the continuous spectrum, i.e., an edge bifurcation may occur. Since the continuous spectrum for the NLS covers the imaginary axis, and since for the CGL it touches the origin, such a bifurcation may lead to an unstable wave. An additional important consideration is that an edge bifurcation can happen even if there are no eigenvalues embedded in the continuous spectrum. Building on and refining ideas first presented in Kapitula and Sandstede (Physica D, 1998) and Kapitula (SIAM J. Math. Anal., 1999), we show that when the wave persists as a regular perturbation, at most three eigenvalues will bifurcate out of the continuous spectrum. Furthermore, we precisely track these bifurcating eigenvalues, and thus are able to give conditions for which the perturbed wave will be stable. For the NLS the results are an improvement and refinement of previous work, while the results for the CGL are new. The techniques presented are very general and are therefore applicable to a much larger class of problems than those considered here.Comment: 41 pages, 4 figures, submitte