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Important Directions (important + direction)
Selected AbstractsNovel nickel-based catalyst for low temperature hydrogen production from methane steam reforming in membrane reformerASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010Yazhong Chen Abstract Hydrogen production from various hydrocarbon fuels, particularly biomass-derived fuels, has attracted worldwide attention due to its potential for application to fuel cells, a device which converts chemical energy into electricity efficiently and cleanly. However, current technology, such as natural gas steam reforming, could not meet the specific requirements of hydrogen for fuel cells. Therefore, novel processes are intensively investigated, aiming to develop economic and efficient ones for the specific purpose. An important direction is the integrated membrane reformer for one-step high-purity hydrogen production. However, for the commercial realization of this technology, there are still some difficulties to overcome. By comparison with previous investigations with a similar membrane, this work showed that catalyst also played an important role in determining membrane reformer performance. We proposed that when thickness of membrane was several micrometers, the permeance of membrane became less important than the kinetics of catalyst, due to the fact that under such conditions, hydrogen permeation rate was faster than the kinetics of steam reforming reaction when commercial catalyst was applied, but further evidence is indispensable. In this initial work, we focused on developing efficient nickel catalyst for low temperature steam reforming. Nickel-based catalyst was developed by deposition,coprecipitation and used as pre-reduced, showing high performance for methane steam reforming at low temperatures and good durability, which may find practical application for the integrated membrane reforming process. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Considering effective divorce mediation: Three potential factorsCONFLICT RESOLUTION QUARTERLY, Issue 4 2002Jerry Gale The purpose of this exploratory, qualitative stgdy was to examine mediator efect by employing a repeated measures research design in which we videotaped mediators working with actors and a scripted divorce case scenario. What factors distinpish higher-rated mediators from lower-rated ones? Our discourse analysys of four divorce mediations suggested three signijcant factors of injuence that finction interactively and afect both mediation outcome and process. Ethical implications regarding how mediators achieve success in these three domains are discussed. This article presents implications for researchers, trainers, and practitioners; it suggests important directions for fiture research with nonsimulated mediation. [source] District magnitude, electoral formula, and the number of partiesEUROPEAN JOURNAL OF POLITICAL RESEARCH, Issue 2 2001KENNETH BENOIT Duverger's propositions concerning the psychological and mechanical consequences of electoral rules have previously been examined mainly through the lens of district magnitude, comparing the properties of single,member district plurality elections with those of multimember proportional representation elections. The empirical consequences of multimember plurality (MMP) rules, on the other hand, have received scant attention. Theory suggests that the effect of district magnitude on the number and concentration of parties will differ with regard to whether the allocation rules are plurality,based or proportional. I test this theory by drawing on a uniquely large,sample dataset where district magnitude and electoral formula vary but the basic universe of political parties is held constant, applying regression analysis to data from several thousand Hungarian local bodies elected in 1994 consisting of municipal councils, county councils, and mayors. The results indicate that omitting the variable of electoral formula has the potential to cause significant bias in estimates of Duvergerian consequences of district magnitude. In addition, the analysis of multi,member plurality elections from the local election dataset reveals counter,intuitively that candidate and party entry may increase with district magnitude under MMP, suggesting important directions for future investigation of MMP rules. [source] Technology and the World the Slaves MadeHISTORY COMPASS (ELECTRONIC), Issue 2 2006Robert Gudmestad The study of American slavery is a crowded field and each year the historical profession witnesses the publication of several new books. Despite this steady onslaught of scholarship, significant gaps remain in our understanding of slavery and its influence on the South. One area that has lacked sustained attention is the nexus of slavery and technological development. Several new books demonstrate that changes in technology profoundly altered the lives and labor of slaves. Historians have approached the presence of technology in a slave society from several different traditions. Some scholars argued that plantation development and mechanical progress were difficult to wed together, while others noted the progressive nature of southern agricultural production, but discussions of white attitudes and behavior overshadowed the effects of machinery on the lives of slaves. An innovative approach has emphasized the employment of slaves in factories, but such works have done little to provide insight into how technological innovation influenced plantation slaves. Several new studies have reversed these trends and promise to lead us in important directions. Examinations of the cotton gin, steamboats, sugar plantations, and clocks have revealed that technology brought enormous change to the bulk of slaves, not just those living in urban areas or working in factories. Patterns and practices of work, opportunities for autonomy, and time away from the master's unstinting gaze, all changed because of mechanical innovation. Taken together, these new works also provide clues to the making and remaking of the southern economy and society. [source] Extended anti-windup control schemes for LTI and LFT systems with actuator saturationsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 15 2004Fen Wu Abstract In this paper, the popular anti-windup control scheme will be extended in two important directions. The first scenario is the control of LTI systems subject to actuators with both magnitude and rate constraints. The second case of extension is LFT systems with input saturations. Based on the extended Circle criterion, we will develop convex anti-windup control synthesis conditions in the form of LMIs for each class of systems. The explicit anti-windup controller formula are also provided to facilitate compensator construction. The effectiveness of proposed anti-windup control schemes will be demonstrated using a flight control example. Copyright © 2004 John Wiley & Sons, Ltd. [source] The Next Generation of Collective Action ResearchJOURNAL OF SOCIAL ISSUES, Issue 4 2009Stephen C. Wright The articles presented in this volume describe part of a new generation of interest and vigor in the social psychological study of collective action. This new wave builds nicely on the foundation set by social identity, self-categorization, and relative deprivation theories but also introduces a number of important innovative perspectives and variables. In this commentary, I review some of these expansions and additions, raise a number of conceptual concerns that arise out of these new directions, and discuss more generally some novel and important directions that emerge from the work presented in the volume and in other recent work on collective action. [source] Trust in digital informationJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 3 2008Kari Kelton Trust in information is developing into a vitally important topic as the Internet becomes increasingly ubiquitous within society. Although many discussions of trust in this environment focus on issues like security, technical reliability, or e-commerce, few address the problem of trust in the information obtained from the Internet. The authors assert that there is a strong need for theoretical and empirical research on trust within the field of information science. As an initial step, the present study develops a model of trust in digital information by integrating the research on trust from the behavioral and social sciences with the research on information quality and human, computer interaction. The model positions trust as a key mediating variable between information quality and information usage, with important consequences for both the producers and consumers of digital information. The authors close by outlining important directions for future research on trust in information science and technology. [source] Maximum likelihood estimation in semiparametric regression models with censored dataJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 4 2007D. Zeng Summary., Semiparametric regression models play a central role in formulating the effects of covariates on potentially censored failure times and in the joint modelling of incomplete repeated measures and failure times in longitudinal studies. The presence of infinite dimensional parameters poses considerable theoretical and computational challenges in the statistical analysis of such models. We present several classes of semiparametric regression models, which extend the existing models in important directions. We construct appropriate likelihood functions involving both finite dimensional and infinite dimensional parameters. The maximum likelihood estimators are consistent and asymptotically normal with efficient variances. We develop simple and stable numerical techniques to implement the corresponding inference procedures. Extensive simulation experiments demonstrate that the inferential and computational methods proposed perform well in practical settings. Applications to three medical studies yield important new insights. We conclude that there is no reason, theoretical or numerical, not to use maximum likelihood estimation for semiparametric regression models. We discuss several areas that need further research. [source] Dentin matrix proteins and soluble factors: intrinsic regulatory signals for healing and resorption of dental and periodontal tissues?ORAL DISEASES, Issue 2 2004TA Silva Dentin contains numerous polypeptides and signaling molecules sequestered in a mineralized matrix. The exposure and release of these molecules occur as a consequence of injury to the pulp and periodontal ligament, which may result from luxation, orthodontic movement or infections of tooth and periodontal structures. When released at these sites, dentin constituents have the potential to act on different surrounding cells, including periodontal cells, osteoblasts, osteoclasts and inflammatory cells, and to affect the course of dental disease. Experimental studies have highlighted the interactions between dentin and cells from tooth and periodontal tissues and reveal dentin to be a cell adhesive, signaling and migratory stimulus for various mesenchymal and inflammatory cells. These results support the hypothesis that dentin molecules might function as regulatory signals for the healing and resorption of dental and periodontal tissues. Data from recent and classical investigations are summarized, many open questions are discussed, and current hypotheses concerning the mechanisms of tooth resorption and periodontal healing are outlined. Many questions regarding the importance of dentin as a source of multifunctional molecules remain unanswered and provide important directions for future studies. [source] Emotion regulation: Affective, cognitive, and social consequencesPSYCHOPHYSIOLOGY, Issue 3 2002James J. Gross One of life's great challenges is successfully regulating emotions. Do some emotion regulation strategies have more to recommend them than others? According to Gross's (1998, Review of General Psychology, 2, 271,299) process model of emotion regulation, strategies that act early in the emotion-generative process should have a different profile of consequences than strategies that act later on. This review focuses on two commonly used strategies for down-regulating emotion. The first, reappraisal, comes early in the emotion-generative process. It consists of changing the way a situation is construed so as to decrease its emotional impact. The second, suppression, comes later in the emotion-generative process. It consists of inhibiting the outward signs of inner feelings. Experimental and individual-difference studies find reappraisal is often more effective than suppression. Reappraisal decreases emotion experience and behavioral expression, and has no impact on memory. By contrast, suppression decreases behavioral expression, but fails to decrease emotion experience, and actually impairs memory. Suppression also increases physiological responding for suppressors and their social partners. This review concludes with a consideration of five important directions for future research on emotion regulation processes. [source] Model selection tests for nonlinear dynamic modelsTHE ECONOMETRICS JOURNAL, Issue 1 2002Douglas Rivers This paper generalizes Vuong (1989) asymptotically normal tests for model selection in several important directions. First, it allows for incompletely parametrized models such as econometric models defined by moment conditions. Second, it allows for a broad class of estimation methods that includes most estimators currently used in practice. Third, it considers model selection criteria other than the models' likelihoods such as the mean squared errors of prediction. Fourth, the proposed tests are applicable to possibly misspecified nonlinear dynamic models with weakly dependent heterogeneous data. Cases where the estimation methods optimize the model selection criteria are distinguished from cases where they do not. We also consider the estimation of the asymptotic variance of the difference between the competing models' selection criteria, which is necessary to our tests. Finally, we discuss conditions under which our tests are valid. It is seen that the competing models must be essentially nonnested. [source] | ||||||||||||||||