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Mecanismo de aglomeración para la recuperación de materia orgánica a partir de jales de plantas lavadoras
No full textDurante los procesos de extracción y beneficio de carbón una gran cantidad de
partículas finas de carbón son generados (>500 mm). En México más de 5
millones de toneladas de finos de carbón son anualmente formadas y
almacenadas en las presas de jales de las Plantas lavadoras de Carbón. Y de
estos residuos, solamente un 20 a 30% de ellos, son utilizados nuevamente,
mientras que el resto son desechados formando residuos con alto valor energético
que está expuesto al medio ambiente.
Es por ello que ante la caída sobre los rendimientos de recuperación de mineral de
valor durante los procesos convencionales de beneficio de carbón como son los
procesos de: medio denso, jiggs, hidro-ciclones y flotación con espuma. Siendo
este último quien normalmente es utilizado para la recuperación de partículas finas
mayores a 500 m. El proceso de flotación, es reportado como un proceso
prometedor para la desulfurización de carbón. Sin embargo, este no parece ser
eficiente cuando el tamaño de partícula es inferior a 28 mallas.
En la actualidad existen algunos procesos alternativos para la recuperación de
partículas de carbón menores a 75 m como son: el proceso de aglomeración con
aceite, el cual es un proceso químico que involucra la adhesión de aceita a una
mezcla de carbón mezclado a alta velocidad para promover la formación de
aglomerados ricos en carbón. Otra proceso alternativo que puede ser combinado
entre el proceso de flotación y microorganismos biológicos, están atrayendo la
atención en todo el mundo. El proceso de bioflotación ha llegado a ser un método
esencial para el beneficio de minerales, ya que la bacteria remplaza a los reactivos
químicos convencionales o bien trabajan en sinergia ambos para producir un alto
grado de concentración con una razonable recuperación de valor.Para este proyecto se evaluó dos procesos químicos y biológicos para desarrollar
un proceso de recuperación de partículas finas de carbón a partir de residuos
mineros.
Para este trabajo se utilizaron dos muestras carbón fino recolectadas de dos
plantas lavadoras de carbón diferente localizadas sobre dos Sub-cuencas
diferentes en la Región Carbonífera de Coahuila. La primera de ellas corresponde
a Sub-cuenca de Rio Escondido (CFM), mientras que la otra muestra pertenece a
la Sub-cuenca Sabinas (CFP). Se utilizaron como colectores en el proceso
químico cuatro reactivos biodegradables conformados por: dos aceites vegetales
(A1O, A2G), un aceite mineral (A3M) y otro automotriz (A4K) y como colectores
biológicos se utilizó la bacteria Staphylococus carnosus.
Los resultados obtenidos de este proyecto indicaron que:
En el proceso químico, los aceites que mostraron una mejor recuperación de
materia orgánica fueron los aceites de tipo vegetal, debido a que requieren de una
menor concentración en peso de aceite (5%wa), comparado con el resto de los
aceites. Finalmente esto para el sector minero resulta ser económicamente
conveniente. La razón es porque los aceites vegetales presentan la ventaja de
contener grupos funcionales oxigenados, que favorecen el proceso de flotación.
Mientras que en el proceso biológico, la formación de biopelícula en la superficie
del mineral de valor, favorece al cambio de la carga superficial de la partícula de
carbón logrando favorecer el proceso de bioflotación, con rendimientos superiores
al 80% en tiempo de flotación de hasta 5 minutos.
Por lo tanto, ambos procesos resultan ser buenas alternativas para la
recuperación de carbón con tamaño mayores a 44m y con apariencia oxidados.
Debido a los tiempos de ambos procesos, el proceso químico resulta ser más
factible para el sector minero, dado que los tiempos de permanencia son menores
comparados al proceso biológico.During the processes of coal extraction and a lot of fine carbon particles are
generated (> 500 mm). In Mexico more than 5 million tons of coal fines are
annually formed and stored in the tailings dams of coal washing plants. And this
waste, only 20-30% of them, are again used, while the rest are discarded forming
high energy waste is exposed to the environment.
That is why before the fall of yields valuable mineral recovery processes for
conventional coal beneficiation processes such as: dense medium, jigs, hydro
cyclones and froth flotation. The latter one is normally used for the recovery of fine
particles larger than 500 m. The flotation process is reported as a promising
process for the desulfurization of coal. However, this does not seem efficient when
the particle size is less than 28 meshes.
At present there are some alternative processes for the recovery of coal particles
less than 75 m as are the oil agglomeration process, which is a chemical process
that involves bonding oiled to a mixture of coal high speed mixing to promote the
formation of agglomerates rich in coal. Another alternative process that can be
combined between the flotation and biological organisms, are attracting attention
worldwide. Bio-flotation process has become an essential method for the
beneficiation of minerals, since bacteria replace conventional chemical reagents or
both work synergistically to produce a high concentration with reasonable recovery
value.
For this project two chemical and biological to develop a process of recovery of fine
coal particles from mining waste processes are evaluated.
For this work two fine coal samples collected from two different coals washing
plants located on two different sub-basins in the Carboniferous Region of Coahuila
plants are used. The first is for Sub-basin of Rio Escondido (CFM), while the other
shows part of the Sub-basin Sabinas (CFP). two vegetable oils (A1O, A2G),
mineral oil (A3M) and other automotive (A4K) and as biological collectors bacteriaStaphylococcus carnosus was used: four reagents comprised of biodegradable
used as collectors in the chemical process.
The results of this project indicated that:
In the chemical process, the oils showed better recovery of organic matter were
vegetal oils, because they require less weight concentration of oil (5% w),
compared with other oils. Finally this for the mining sector turns out to be
economically convenient. The reason is that vegetable oils have the advantage of
containing oxygenated functional groups, favoring the flotation process.
While in the biological process, biofilm formation on the surface of mineral value,
favors change the surface charge of the coal particle making process bio-flotation
promote, with yields higher than 80% by flotation time up 5 minutes.
Therefore, both processes are good alternatives for recovering larger sized coal
and oxidized 44m appearance. Because the times of both processes, the
chemical process turns out to be more feasible for the mining sector, as dwell
times are minor compared to the biological process
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
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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