1,721,009 research outputs found
Orientation dynamics of anisotropic and polydisperse colloidal suspensions
Get PDFSmall-angle light scattering (SALS) is employed to determine in situ microstructural changes of polydisperse colloidal suspensions under capillary flow. Titanium dioxide (rod-like) bundles and kaolinite nanoclay (platelet) flake-like stacks of particles are suspended in a Newtonian fluid to explore the effects of shape anisotropy. Subjecting the systems to a startup test in a flow cell in Stokes's regime, the evolution of the anisotropy factor (AF), and the average orientation angle (χ) of particles vs strain is probed at different averaged Péclet ([Formula: see text]) numbers. Dilute and semi-dilute concentration regimes are explored in a capillary flow. Moving in the vorticity direction, we show significant changes in χ due to the gradient in shear rate in the capillary flow, while no cross-sectional flow migration was exhibited. In these polydisperse colloidal suspensions, two characteristic stages are observed: initial particle alignment and subsequent orientational demixing. Probing the velocity–vorticity (xy) plane, an initial particle alignment in the flow direction at high [Formula: see text] (> 1) occurs, is demonstrated by an elliptical SALS pattern, and then, an increase in AF is observed due to particles' phase mixing. This behavior is then followed by a breakdown in structure and loss of particle alignment due to orientational demixing. The evolution of the average orientation angle of particles in the xy plane can be clearly observed through these two stages by the help of high-resolution SALS contours. These experimental findings provide novel insights into the flow–microstructure relationship of polydisperse colloidal suspensions for the optimization of many industrial processing schemes.</jats:p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Feasibility Analysis on Geothermal Heat Storage Capacity and Recovery of Alberta’s Decommissioned Wells
No full textprovince of Alberta is home to one of the World’s largest strategic sedimentary basins. The Oil and Gas industry has been Alberta’s major source of economic prosperity for more than half a century. There are plenty of related environmental concerns with the oil and gas operations. The Earth’s thermal energy potential known as Geothermal is one the most reliable sustainable energy sources with the least negative environmental impacts. In this capstone project, a feasibility analysis with numerical model was performed for heat storage and recovery, to create synthetic geothermal reservoirs in Alberta’s cold shallow formations. Additionally, an analytical model was created to recover sustainable heat for space heating applications from hot deep deposited formations using the decommissioned wells. The objective of this study is to provide a sustainable solution to meet some of the Alberta’s growing energy mix demand for the future while lowering the GHG emissions and negative environmental impacts of the abandoned oil and gas wells
The Case for Energy Storage in Alberta, Canada
No full textAround the world, power grids are evolving. They represent a point of convergence for a wide range of policy objectives from economic growth to climate change mitigation. This is the case in the province of Alberta, home of a deregulated electricity market that connects Western Canada to the wider North American Bulk Electric System. Technological advancements and environmental mandates have altered how electricity is produced, distributed, and consumed. Energy storage can help the Alberta Electric System Operator navigate this transition by providing valuable grid services that ensure system reliability and optimize renewable generation. Pumped hydroelectric, lithium ion batteries, compressed air, thermal energy storage, flywheels, and hydrogen fuel cells will be evaluated for feasibility in Alberta. It was found that the deployment of lithium ion batteries and flywheels would best support the energy and regulatory requirements of the Alberta Interconnected Electric System
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Techno-Economic Study on Aircraft Emissions Reduction at YYC Calgary International Airport
No full textA techno-economic study was conducted to identify a set of financial schemes and operational practices that the Calgary Airport Authority can implement to reduce aircraft ground emissions at the YYC Calgary International Airport in three key operational areas: (i) ground support equipment (GSE), (ii) aircraft engines, and (iii) aircraft gate operations. Analysis of the aircraft’s path from taxiing to gate operations shows that energy efficiencies and emission reductions ranging from 85% to 95% could be achieved. These findings are based on models where aircraft are towed to the gate by external electric GSE, the Auxiliary Power Unit (APU) is disconnected and powered by an electric Ground Power Unit (GPU), and all-electric or mixed GSE fleet configurations are used to service the aircraft at the gate. This study proposes an incentive-penalty approach to improve performance in GSE anti-idling practices and APU substitution to reduce emissions
Closed Loop Cryptocurrency Mining in Alberta
No full textIn the highly connected age of information and data, the push for the development of ‘clean data’ has necessitated sustainability strategies for data centers. Green innovations are increasingly implemented to reduce the formidable power consumption of inefficient computing processes while heat reuse solutions repurpose the large volumes of server waste heat, decreasing facility footprint. This project examined the efficiency optimization potential of co-located power generation and greenhouse waste heat reuse for cryptocurrency data center platforms in Alberta. The proposed 45 MW data center capitalized on favorable climatic conditions to reduce energy requirements, improving facility efficiency and decreasing theoretical PUE values from 2.13 to 1.51. Resultant waste heat sufficiently supplied year-round heating to an 8.34-acre greenhouse suitable for commercial cannabis growth. The total annual avoided emissions for this proposed system were calculated at 70,000 tonnes of CO2, illustrating the potential of integrated economizer cyles and waste heat reuse in Alberta
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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