2,126 research outputs found

    The bluff body stabilized premixed flame in an acoustically resonating tube: combustion CFD and measured pressure field

    Get PDF
    The resulting limit cycle amplitude and frequency spectrum of a flame placed in a combustor of rectangular cross section is investigated. The partially premixed flame is stabilized on a bluff body placed in the upstream half of the combustor. The bluff body is an equilateral triangular wedge with one of the edges pointing in upstream direction. Acoustically there is an open downstream end and theer are variable acoustic conditions at the upstream end.\ud In order to assess the properties of the flame in this combustor, steady state flame simulations have been performed of the flame in the enclosure. These provided the fields of the mixing of gases, temperature and the velocity.\ud A test rig was manufactured for this burner at the University of Twente. In a first set of experiments, gas temperature, pressure field and flame chemiluminescence in the combustor were measured as a function of power and acoustic inlet condition. It was observed that the combustor exhibited strong natural pressure oscillations. The measured pressure, temperature and chemiluminescence data are compared to the CFD simulations and to numerical calculations of the acoustics presented in a companion paper by M.Heckl

    Rough Set Applied to Air Pollution: A New Approach to Manage Pollutions in High Risk Rate Industrial Areas

    Get PDF
    This study presents a rough set application, using together the ideas of classical rough set approach, based on the indiscernibility relation and the dominance-based rough set approach (DRSA), to air micro-pollution management in an industrial site with a high environmental risk rate, such as the industrial area of Syracuse, located in the South of Italy (Sicily). This new data analysis tool has been applied to different decision problems in various fields with considerable success, since it is able to deal both with quantitative and with qualitative data and the results are expressed in terms of decision rules understandable by the decision-maker. In this chapter, some issue related to multi-attribute sorting (i.e. preference-ordered classification) of air pollution risk is presented, considering some meteorological variables, both qualitative and quantitative as attributes, and criteria describing the different objects (pollution occurrences) to be classified, that is, different levels of sulfur oxides (SOx), nitrogen oxides (NOx), and methane (CH4) as pollution indicators. The most significant results obtained from this particular application are presented and discussed: examples of ‘if, … then’ decision rules, attribute relevance as output of the data analysis also in terms of exchangeable or indispensable attributes/criteria, of qualitative substitution effect and interaction between them

    Design, Synthesis and Study of Novel Nucleobase Analogs

    Get PDF
    This thesis focused on nucleobase modified peptide nucleic acid (PNA) and DNA to expand the repertoire of available nucleobase analogs used in the study of nucleic acids. More specifically, we are interested in modification of the nucleobases such that they retain their ability to undergo Watson-Crick base pairing. Moreover, our goal is to modify the nucleobases in order to engender them with useful photophysical properties such that they may be used as biomolecular tools to investigate nucleic acid structure and dynamics. To that end, a derivative of 5-aminouracil (5-AU) labelled with the amine-reactive chromophore 9-chloroacridine was prepared for the purpose of investigating its potential as a base-discriminating fluorophore. This modified nucleobase was incorporated into PNA by fluorenylmethyloxycarbonyl (Fmoc)-based oligomerization chemistry. During study of its hybridization to complementary DNA (cDNA), the 5-substitution was found to be thermally labile and hydrolyzed to a small degree in neutral aqueous solution, thus liberating the highly fluorescent acridone moiety. Moreover, three novel fluorescent 7-deaza-2´-deoxyadenosine analogs were successfully synthesized via the Sonogashira cross-coupling reaction of 7-iodo-7-deaza-2´-deoxyadenosine with 1-ethynylpyrene, 2-ethynyl-6-methoxynaphthalene, and 9-ethynylphenanthrene. These analogs were photophysically characterized in dioxane, EtOH, and H2O to evaluate their potential for use as environmentally sensitive fluorescent probes. All three analogs displayed high solvatofluorochromicity in H2O, relative to their emission wavelengths in dioxane and EtOH. Moreover, all three analogs exhibited moderate to high fluorescence quantum yields in dioxane and EtOH, and significantly lower fluorescence quantum yields in H2O, indicating that these analogs display microenvironment sensitivity. Furthermore, the synthesis towards a novel tricyclic adenine analog was attempted by extending the substrate scope of the Sonogashira cross-coupling/heteroannulation chemistry developed in the Hudson groupfor cytidine analogs to adenine analogs. However, unlike the cytidine scaffold, the 7-deazaadenine substrate did not cyclize under the Sonogashira cross-coupling/heteroannulation reaction conditions to give the tricyclic adenine and the straight cross-coupled product was obtained in moderate yield. Lastly, an intrinsic nucleobase quencher was synthesized via the azo coupling reaction between 5-diazouracil and N,N-dimethylaniline. Fluorescence quenching experiments were performed between the nucleobase quencher and the fluorophores phenylpyrrolocytidine (pC), and pyrene to determine viable FRET pairs for use in molecular beacon constructs

    Asymptotic solutions of the Dirichlet problem for the heat equation with impulses

    No full text
    We propose an algorithm for the construction of asymptotic expansions for solutions of the Dirichlet problem for the heat equation with impulses.Запропоновано алгоритм побудови асимптотичних розвинень для розв'язків задачі Діріхле для рівняння теплопровідності з імпульсною дією

    Post-2020 EU Roma Strategy: The Way Forward

    Get PDF
    The 2011 EU Framework for National Roma Integration Strategies (the EU Roma Framework) set ambitious goals to close the gap between Roma and non-Roma in education, employment, housing, and health, as well as to protect Roma against discrimination. While there have been many achievements since 2011, the EU Roma Framework has failed to reach its goals in all policy areas, including combating discrimination. Its objectives were unrealistic and did not consider crucial missing elements.This report recommends the creation of a fully-fledged strategy on Roma and the EU, not just a framework, and how to make future goals more concrete and achievable

    Influences of a Luck Game on Offers in Ultimatum and Dictator Games: Is There a Mediation of Emotions?

    Get PDF
    The ultimatum (UG) and dictator (DG) games are two tasks where a sum of money has to be divided between two players: a proposer and a receiver. Following the rational choice theory, proposers should offer the minimum in the UG and nothing in the DG, due to the presence/absence of the receivers’ bargaining power. The fact that people generally make non-negligible offers in both games has suggested divergent explicative hypotheses and has generated extensive research to examine exogenous and endogenous factors underlying such decisions. Among the contextual factors affecting the proposers’ offers, the sense of entitlement or of ownership has been shown to reduce offers significantly. A frequent way to induce the sense of entitlement/ownership has been to assign the role of proposer to the player who apparently has better scored in skill tasks executed before the UG or DG or has more contributed, through a previous luck game, to the amount to be shared. Such manipulations, however, could produce a possible overlapping between “ownership” and “merit,” that in this study we aimed to disentangle. We manipulated the participants’ initial endowment through a luck game, by increasing, decreasing or leaving it unchanged, to investigate whether winnings or losses by chance influenced offers in UG and DG in similar or different ways depending on their respective features. All participants played as proposers but this role was apparently random and disconnected from the outcomes of the luck game. Furthermore, we investigated whether the putative effect of experimental manipulation was mediated by the changes in emotions elicited by the luck game and/or by the emotions and beliefs related to decision-making. We used a non-economic version of the games, in which tokens were divided instead of money. In the study, 300 unpaid undergraduates (M = 152) from different degree programs, aged between 18 and 42 years, participated. The results revealed that the effect of outcome manipulation on offers was moderated by the specific structure of the UG and DG. Instead, emotional reactions barely mediated the effect of the experimental manipulation, suggesting that their role in those decisions is less relevant than is assumed in the literature
    corecore