821 research outputs found

    Investigating the Effects of Flue Gas Injection, Hot Water Distribution, and Fill Distribution on Natural Draft Wet Cooling Tower Performance

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    Natural draft wet cooling towers (NDWCT) are a common method of heat removal in powerplants. This study employs a numerical cooling tower model developed by Eldredge, Benton & Hodgson (1997) to examine whether utilizing nonuniform water, fill profiles, and flue gas injection can improve NDWCT efficiency. The results show that each of these variables can be optimized to lower outlet water temperature. Within the range tested for each parameter, the water profile had the most significant effect on outlet water temperature, followed by the flue gas temperature and then the fill profile. The optimum parameter combination reduced the predicted outlet water temperature by 0.5 °C which corresponds to annual fuel savings of up to 55 million dollars and 1.83 million metric tons of carbon dioxide for fossil plants in the United States

    Down but Not Out: Reforming Social Assistance Rules that Punish the Poor for Saving

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    Reform is required for social program rules that prevent the poor from saving in Registered Retirement Savings Plans (RRSPs) and Tax Free Savings Accounts (TFSAs), according to this study. The author says that encouraging asset accumulation, even in small amounts, is crucial in helping to lift people out of poverty. Yet most Canadian welfare, disability and social service programs deny or cancel benefits if applicants or recipients place a modest level of savings in an RRSP or TFSA. Barring a province-led effort at reform, says Stapleton, the federal government should take the lead by calling on provinces and territories to exempt meaningful RRSP and TFSA amounts from their welfare asset rules, leaving individual jurisdictions to decide the appropriate levels.Social Policy, Registered Retirement Savings Plan (RRSP), Tax Free Savings Account (TFSA), social assistance

    No Strings Attached: How The Tax-Free Savings Account Can Help Lower-Income Canadians Get Ahead

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    The federal government’s new Tax-Free Savings Accounts (TFSAs) can help correct the problem of government clawback provisions that discourage or effectively prohibit spersonal saving, provided that provinces and territories refrain from imposing new asset tests and clawbacks that undo savers’ potential gains.fiscal policy, tax-free savings accounts (TFSA)

    A Normal Form for Spider Diagrams of Order

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    We develop a reasoning system for an Euler diagram based visual logic, called spider diagrams of order. We de- fine a normal form for spider diagrams of order and provide an algorithm, based on the reasoning system, for producing diagrams in our normal form. Normal forms for visual log- ics have been shown to assist in proving completeness of associated reasoning systems. We wish to use the reasoning system to allow future direct comparison of spider diagrams of order and linear temporal logic

    A New Language for the Visualization of Logic and reasoning

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    Many visual languages based on Euler diagrams have emerged for expressing relationships between sets. The expressive power of these languages varies, but the majority can only express statements involving unary relations and, sometimes, equality. We present a new visual language called Visual First Order Logic (VFOL) that was developed from work on constraint diagrams which are designed for software specification. VFOL is likely to be useful for software specification, because it is similar to constraint diagrams, and may also fit into a Z-like framework. We show that for every First Order Predicate Logic (FOPL) formula there exists a semantically equivalent VFOL diagram. The translation we give from FOPL to VFOL is natural and, as such, VFOL could also be used to teach FOPL, for example

    On the Completeness of Spider Diagrams Augmented with Constants

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    Diagrammatic reasoning can be described formally by a number of diagrammatic logics; spider diagrams are one of these, and are used for expressing logical statements about set membership and containment. Here, existing work on spider diagrams is extended to include constant spiders that represent specific individuals. We give a formal syntax and semantics for the extended diagram language before introducing a collection of reasoning rules encapsulating logical equivalence and logical consequence. We prove that the resulting logic is sound, complete and decidable

    Some Results for Drawing Area Proportional Venn3 With Convex Curves

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    Many data sets are visualized effectively with area proportional Venn diagrams, where the area of the regions is in proportion to a defined specification. In particular, Venn diagrams with three intersecting curves are considered useful for visualizing data in many applications, including bioscience, ecology and medicine. To ease the understanding of such diagrams, using restricted nice shapes for the curves is considered beneficial. Many research questions on the use of such diagrams are still open. For instance, a general solution to the question of when given area specifications can be represented by Venn3 using convex curves is still unknown. In this paper we study symmetric Venn3 drawn with convex curves and show that there is a symmetric area specification that cannot be represented with such a diagram. In addition, by using symmetric diagrams drawn with polygons, we show that, if area specifications are restricted so that the double intersection areas are no greater than the triple intersection area then the specification can be drawn with convex curves. We also propose a construction that allows the representation of some area specifications when the double intersection areas are greater than the triple intersection area. Finally, we present some open questions on the topic

    Drawing Area-Proportional Euler Diagrams Representing Up To Three Sets

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    Area-proportional Euler diagrams representing three sets are commonly used to visualize the results of medical experiments, business data, and information from other applications where statistical results are best shown using interlinking curves. Currently, there is no tool that will reliably visualize exact area-proportional diagrams for up to three sets. Limited success, in terms of diagram accuracy, has been achieved for a small number of cases, such as Venn-2 and Venn-3 where all intersections between the sets must be represented. Euler diagrams do not have to include all intersections and so permit the visualization of cases where some intersections have a zero value. This paper describes a general, implemented, method for visualizing all 40 Euler-3 diagrams in an area-proportional manner. We provide techniques for generating the curves with circles and convex polygons, analyze the drawability of data with these shapes, and give a mechanism for deciding whether such data can be drawn with circles. For the cases where non-convex curves are necessary, our method draws an appropriate diagram using non-convex polygons. Thus, we are now always able to automatically visualize data for up to three sets

    How Should We Use Colour in Euler Diagrams?

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    This paper addresses the problem of how best to use colour in Euler diagrams. The choice of using coloured curves, rather than black curves, possibly with coloured fill is often made in tools that automatically draw Euler diagrams for information visualization as well as when they are drawn manually. We address the problem by empirically evaluating various different colour treatments: coloured or black curves combined with either no fill or coloured fill. By collecting performance data, we conclude that Euler diagrams with coloured curves and no fill significantly outperform all other colour treatments. Most automated layout algorithms adopt colour fill and are, thus, reducing the effectiveness of the Euler diagrams produced. As Euler diagrams can be used in a multitude of areas, ranging from crime control to social network analysis, our results stand to increase the ability of users to accurately and quickly extract information from their visualizations

    Does the Orientation of an Euler Diagram Affect User Comprehension?

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    Euler diagrams, which form the basis of numerous visual languages, can be an effective representation of information when they are both well-matched and well-formed. However, being well-matched and well-formed alone does not imply effectiveness. Other diagrammatical properties need to be considered. Information visualization theorists have known for some time that orientation has the potential to affect our interpretation of diagrams. This paper begins by explaining why well-matched and well-formed drawing principles are insufficient and discusses why we should study the orientation of Euler diagrams. To this end an empirical study is presented, designed to observe the effect of orientation upon the comprehension of Euler diagrams. The paper concludes that the orientation of Euler diagrams does not significantly affect comprehension
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