The Impact of Biodiesel-based Na on the Durability of Cu-Zeolite SCR Catalysts and Other Diesel Aftertreatment Devices

Biodiesel fuel has increased in popularity in recent years as an alternative fuel choice, but there are concerns related to the impact it will have on diesel engines and aftertreatment systems relative to conventional diesel fuel. One major concern is the presence of sodium (Na) in finished biodiesel fuel due to the use of Na-hydroxyl as a liquid-phase catalyst during biodiesel synthesis. The current study focuses on determining the impact of biodiesel-based Na on the performance and materials characterization of diesel aftertreatment devices including lean NOx traps (LNT), diesel oxidation catalysts (DOC), diesel particulate filters (DPF), and Cu-zeolite selective catalytic reduction (SCR) catalysts. Long-term engine aged LNT, DOC, and DPF samples are provided by research partners, while a 517 cc single-cylinder Hatz diesel engine is used to perform accelerated Na-aging of aftertreatment systems consisting of a DOC, SCR, and DPF in either the light-duty (DOC-SCR-DPF) or heavy-duty (DOC-DPF-SCR) configuration. Bench-flow reactor (BFR) evaluations reveal that the performance of LNT and DOC catalysts is negligibly affected by exposure to Na, but that Cu-zeolite SCR in the light-duty configuration suffers a drastic reduction in nitrogen oxide (NOx) performance. The performance loss can be avoided by placing the SCR downstream of the DPF in the heavy-duty aftertreatment configuration, but electron microprobe analysis (EPMA) of the DPF from this configuration identifies excessive Na ash buildup and migration of Na into the DPF substrate. v EPMA analysis of the Na-aged SCR determined that the contamination pattern is similar to that observed in the long-term engine-aged DOC and LNT samples, providing credibility to the accelerated Na-aging process. Materials characterization techniques including diffuse-reflective infrared Fourier transform spectroscopy (DRIFTS), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and BET surface area measurements determined that loss of catalyst surface area and a decrease in the number of active Cu sites for ammonia (NH3) adsorption and SCR reactions are the most likely cause of the reduced nitrogen oxides (NOx) performance in the light-duty configuration accelerated Na-aged SCR. Finally, mathematical modeling successfully predicts the performance of fresh SCR catalysts, but is less accurate for catalysts exposed to elevated levels of Na

Factors Associated with Family Counseling Practices: The Effects of Training, Experience, and Multicultural Counseling Competence

The ACA code of ethics encourages the inclusion of family in the therapeutic process when doing so can be considered positive (ACA, 2014). Additionally, family dynamics are an important component of counseling for clients from diverse cultural backgrounds. A critical review of the literature reveals that there are differences between conceptual and physical inclusions of families in counseling. Counselors can use a family systems theoretical lens and or incorporate family-based interventions. The purpose of this study was to investigate how counselors include families in counseling and what factors are associated with family counseling practice. Variables assessed include training and coursework, experience, and multicultural competence. A MANOVA showed that there is a significant difference between family counseling practice groups (High, Low, Inconsistent) and the multivariate dependent variables. Post Hoc analysis further described these differences as being focused on training in family counseling and also in reported multicultural counseling competence (as measured by the MCKAS). Limitations, implications for training and practices, and future directions for research are discussed

Synthetic sequence generator for recommender systems - memory biased random walk on sequence multilayer network

Personalized recommender systems rely on each user's personal usage data in the system, in order to assist in decision making. However, privacy policies protecting users' rights prevent these highly personal data from being publicly available to a wider researcher audience. In this work, we propose a memory biased random walk model on multilayer sequence network, as a generator of synthetic sequential data for recommender systems. We demonstrate the applicability of the synthetic data in training recommender system models for cases when privacy policies restrict clickstream publishing.Comment: The new updated version of the pape

Variable length-based genetic representation to automatically evolve wrappers

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-12433-4_44Proceedings 8th International Conference on Practical Applications of Agents and Multiagent SystemsThe Web has been the star service on the Internet, however the outsized information available and its decentralized nature has originated an intrinsic difficulty to locate, extract and compose information. An automatic approach is required to handle with this huge amount of data. In this paper we present a machine learning algorithm based on Genetic Algorithms which generates a set of complex wrappers, able to extract information from theWeb. The paper presents the experimental evaluation of these wrappers over a set of basic data sets.This work has been partially supported by the Spanish Ministry of Science and Innovation under the projects Castilla-La Mancha project PEII09-0266-6640, COMPUBIODIVE (TIN2007-65989), and by V-LeaF (TIN2008-02729-E/TIN)

Modeling practical thinking

Intellectualists about knowledge how argue that knowing how to do something is knowing the content of a proposition (i.e, a fact). An important component of this view is the idea that propositional knowledge is translated into behavior when it is presented to the mind in a peculiarly practical way. Until recently, however, intellectualists have not said much about what it means for propositional knowledge to be entertained under thought's practical guise. Carlotta Pavese fills this gap in the intellectualist view by modeling practical modes of thought after Fregean senses. In this paper, I take up her model and the presuppositions it is built upon, arguing that her view of practical thought is not positioned to account for much of what human agents are able to do

The nature of an object-oriented program:how do practitioners understand the nature of what they are creating?

Object-oriented programming is seen as a difficult skill to master. There is considerable debate about the most appropriate way to introduce novice programmers to object-oriented concepts. Is it possible to uncover what the critical aspects or features are that enhance the learning of object-oriented programming? Practitioners have differing understandings of the nature of an object-oriented program. Uncovering these different ways of understanding leads to agreater understanding of the critical aspects and their relationship tothe structure of the program produced. A phenomenographic studywas conducted to uncover practitioner understandings of the nature of an object-oriented program. The study identified five levels of understanding and three dimensions of variation within these levels. These levels and dimensions of variation provide a framework for fostering conceptual change with respect to the nature of an object-oriented program

Local Causal States and Discrete Coherent Structures

Coherent structures form spontaneously in nonlinear spatiotemporal systems and are found at all spatial scales in natural phenomena from laboratory hydrodynamic flows and chemical reactions to ocean, atmosphere, and planetary climate dynamics. Phenomenologically, they appear as key components that organize the macroscopic behaviors in such systems. Despite a century of effort, they have eluded rigorous analysis and empirical prediction, with progress being made only recently. As a step in this, we present a formal theory of coherent structures in fully-discrete dynamical field theories. It builds on the notion of structure introduced by computational mechanics, generalizing it to a local spatiotemporal setting. The analysis' main tool employs the \localstates, which are used to uncover a system's hidden spatiotemporal symmetries and which identify coherent structures as spatially-localized deviations from those symmetries. The approach is behavior-driven in the sense that it does not rely on directly analyzing spatiotemporal equations of motion, rather it considers only the spatiotemporal fields a system generates. As such, it offers an unsupervised approach to discover and describe coherent structures. We illustrate the approach by analyzing coherent structures generated by elementary cellular automata, comparing the results with an earlier, dynamic-invariant-set approach that decomposes fields into domains, particles, and particle interactions.Comment: 27 pages, 10 figures; http://csc.ucdavis.edu/~cmg/compmech/pubs/dcs.ht

Impact of Fuel Metal Impurities on the Durability of a Light-Duty Diesel Aftertreatment System

Alkali and alkaline earth metal impurities found in diesel fuels are potential poisons for diesel exhaust catalysts. A set of diesel engine production exhaust systems was aged to 150,000 miles. These exhaust systems included a diesel oxidation catalyst, selective catalytic reduction (SCR) catalyst, and diesel particulate filter (DPF). Four separate exhaust systems were aged, each with a different fuel: ultralow sulfur diesel containing no measureable metals, B20 (a common biodiesel blend) containing sodium, B20 containing potassium, and B20 containing calcium, which were selected to simulate the maximum allowable levels in B100 according to ASTM D6751. Analysis included Federal Test Procedure emissions testing, bench-flow reactor testing of catalyst cores, electron probe microanalysis (EPMA), and measurement of thermo-mechanical properties of the DPFs. EPMA imaging found that the sodium and potassium penetrated into the washcoat, while calcium remained on the surface. Bench-flow reactor experiments were used to measure the standard nitrogen oxide (NOx) conversion, ammonia storage, and ammonia oxidation for each of the aged SCR catalysts. Vehicle emissions tests were conducted with each of the aged catalyst systems using a chassis dynamometer. The vehicle successfully passed the 0.2 gram/mile NOx emission standard with each of the four aged exhaust systems