1,720,956 research outputs found
Diseño y construcción de un equipo didáctico de acondicionamiento de aire tipo "Mini Split", para el laboratorio de refrigeración de la Universidad Pontificia Bolivariana
No full text110 p.La contaminación y los cambios climáticos son fenómenos que se han venido presentando durante los últimos años, adquiriendo cada vez más fuerza. Por esta razón las personas buscan tener mejores condiciones ambientales haciendo uso de los sistemas de acondicionamiento de aire. Este trabajo de grado consiste en el diseño y construcción de un equipo de acondicionamiento de aire tipo mini split con fines educativos, con este se pretende mostrar el proceso de instalación que requieren estos equipos, el ahorro significativo que puede llegar a tener una instalación adecuada siguiendo las prácticas de instalación, mantenimiento y uso recomendadas, el monitoreo de las variables involucradas en el proceso por medio de unos sensores de presión y temperatura, se ubicará un medidor del consumo energético para observar el comportamiento del equipo bajo diferentes condiciones de operación. En el ciclo de refrigeración correspondiente se emplea el refrigerante R410A (implementado en este trabajo). Para ello se elaboró una estructura (chasis) en perfiles de aluminio en la cual se ubican las unidades del mini Split que son el evaporador y el condensador. La principal característica del diseño del equipo es la parte didáctica la cual permite por medio de unas guías elaboradas para el laboratorio de la Universidad Pontificia Bolivariana (CIRCLI) que todos los estudiantes de pregrado, postgrado e inclusive técnicos, medir y controlar las variables del proceso, con esto se puede monitorear posibles fallas, malas prácticas, fugas de líquido refrigerante, obstrucciones, entre otras y realizar un plan de mantenimiento adecuado a apuntando a la reducción del consumo energético de estos equipos
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
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
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
Análisis comparativo de sistemas de refrigeración doméstica utilizando refrigerantes R600a y R134a
No full textThis article presents a comparative analysis of three no frost refrigerators same characteristics that work with refrigerant HC R600a and HFC R134a. For analyzing the measured operating temperature, also the power consumption is determined and finally the coefficient of performance (COP) for each set is calculated. The three domestic refrigerators used were the same model and capacity with the difference that a 1/4 hp compressor charged with R134a used in the first and in the other two coolers compressors used 1/4 hp and 1/6 hp charged with R600a. From this it was determined that the COP of the refrigerator with R600a and 1/4 hp compressor is 2.7 and to 1/6 hp compressor is 4.8, whereas with R134a and 1/4 hp compressor is 3.5 ; also the maximum temperatures reached on the elements of the cooling system and charged with R600a 1/6 hp compressor were -33.92 °C to the evaporator income, 60.73 °C at the outlet of the compressor, 37.53 °C to the compressor income and 36.75 °C at the condenser outlet.Este artículo presenta un análisis comparativo de tres refrigeradores no frost de iguales características, que funcionan con refrigerante HC R600a y refrigerante HFC R134a. Para el análisis se midió las temperaturas de funcionamiento, además se determinó el consumo de energía y, por último, se calculó el coeficiente de desempeño (COP) para cada caso. Los tres refrigeradores domésticos utilizados fueron de igual modelo y capacidad, con la diferencia que en el primero se utilizó un compresor de 1/4 hp cargado con R134a, mientras en los otros dos refrigeradores se utilizó compresores de 1/4 hp y 1/6 hp cargados con R600a. De esta dinámica se determinó que el COP del refrigerador con R600a y compresor de 1/4 hp es de 2.7 y con el compresor de 1/6 hp es de 4.8, mientras que con el refrigerante R134a y compresor de 1/4 hp es de 3.5; además las temperaturas máximas alcanzadas en los elementos del sistema de refrigeración cargado con R600a y compresor de 1/6 hp fueron de -33.92°C al ingreso del evaporador, 60.73°C a la salida del compresor, 37.53°C al ingreso del compresor y 36.75°C a la salida del condensador
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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