1,720,953 research outputs found
Caratteristiche chimico fisiche dell’argilla espansa: inclusione di ioni metallici.
No full textL’orientamento della UE in materia di riduzione dell’inquinamento ambientale riguarda ormai tutti i prodotti e/manufatti immessi sul mercato, che devono essere in qualche modo certificati per quanto riguarda le emissioni o rilasci nell’ambiente [1, 2].
Il recupero di rifiuti nei cicli di produzione esistenti, favorito da numerose norme europee e nazionali nell’ottica di risparmio di materie prime e combustibili fossili, viene attuato in numerose industrie manifatturiere che impiegano processi ad elevata temperatura, quali l’industria del cemento, dei laterizi, dell’argilla espansa, della ceramica ecc. [3 - 8].
Il processo di produzione standard dell’argilla espansa consiste nel trattamento di un’adatta qualità di argilla con quantità fissate di acqua ed olio a temperatura elevata (circa 1200°C) in modo da ottenere il materiale con le caratteristiche desiderate.
Nel processo sono vantaggiosamente utilizzati combustibili di recupero (rifiuti) quali oli ed emulsioni oleose esausti, solventi esausti, acque ad elevato COD, contenenti piccole quantità di ioni metallici, dell’ordine dei mg / dm3.
Tale pratica immette nel prodotto finale piccole quantità di metalli (ossidi metallici) in esubero rispetto a quanto contenuto nelle materie prime naturali che, alle alte temperature del processo, sono inglobati nella matrice argillosa o cementizia.
L’obiettivo di questo lavoro è di valutare la possibilità di fissare nell’argilla quantità differenti di cationi o di altre specie chimiche in modo irreversibile. Ciò costituirebbe una prova definitiva che un processo di produzione che comporta l’uso di materiale contenente le specie chimiche considerate o loro derivati, non provoca nocumento significativo all’ambiente.
L’indagine è stata condotta in laboratorio confrontando il comportamento al dilavamento di campioni di argilla preparata secondo il “processo normale” e di campioni di argilla preparati con l’aggiunta di soluzioni acquose contenenti quantità crescenti di Cd, Pb, Cr III, Cr VI.
I campioni di argilla preparati con l’aggiunta dei cationi sopra citati sono stati messi a dibattere, secondo la normativa, con un volume di soluzione di tampone acetato a pH = 5 pari a 16 volte quello del solido da estrarre. In alternativa la soluzione tampone era sostituita da acqua [9 - 11].
Nel test di dilavamento del Cromo (VI), il campione era messo a contatto con acqua distillata invece che con il tampone acido acetico/acetato, secondo quanto suggerito dalla norma UNI 10802 [12].
Altra parte dei campioni preparati con l’aggiunta di quantità note di cationi veniva analizzata [13] per verificare che la quantità aggiunta dei cationi veniva ritrovata nel solido.
Entrambi i saggi davano risultati positivi. Le quantità di cationi trovate nelle soluzioni di dilavamento erano molto basse se non al disotto dei limiti di determinazione dell’assorbimento atomico (valori dell’ordine dei ppb). La quantità di cationi trovata nel solido concordava a meno dell’errore sperimentale (entro ± 2 %) con la quantità inizialmente addizionata.
In ogni caso, la concentrazione di ioni metallici nell’acqua di dilavamento era trascurabile in confronto con quella generalmente ammessa nell’acqua potabile [14 - 15].
Ringraziamenti. Si ringrazia la soc. Laterlite S.p.A. che ha reso possibile la realizzazione di questo lavoro.
Bibliografia
[1] M.Giugliano and E. Paggi (1985), Waste Management and Research, 3, 361-368.
[2] H. Skinner (1986), Proceedings of the SEP Pollution, Padova, 267-291.
[3] Council CEE, regulatory 96/61/CEE of 24 September 1996.
[4] CEE- regulatory framework for Registration, Evaluation and Authorisation of Chemicals, 29 October 2003
[5] D.L. n. 152 of 11 May 1999.
[6] “Documento di riferimento sulle BAT nell’industria dell’argilla espansa” – Aprile 2006.
[7] A. Bossi and E. Brustia (1985), Inquinamento, n. 7/8, 75-80.
[8] A. Bossi, U Ghezzi, M. Giugliano, C. Ortolani and A. Rolla (1986), Proceedings of 5th International Recycling Congress and Exhibition, Berlin, October 29-31.
[9] W.M.A. Kox, and E. Van der Vlist (1981), Conservation and Recycling, n.4, 29-38
[10] Lombardy Region – Regional Regulations n. 3 of 9 January 1982.
[11] D.C.I.M. - 27/07/1984.
[12] Rule UNI 10082 - D.M. 13/01/03.
[13] G. Schwarzenbach and H. Flaska, (1965), Die komplexometrische Titration, F.E. Verlag, Stuttgart
[14] D.L. n° 31 of 02/02/2001, relative to directive 98/83/CE, regarding the water quality
devoted to human use.
[15] D.M. of 29 December 2003, regulatory 2003/40/CE, G.U.R.I. n. 302, 31/12/2003
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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