1,721,000 research outputs found
Phosphorous removal and recovery methods. An application on a real municipal wastewater treatment plant.
Full text linkIl fosforo (P) è un elemento chiave nell’approvvigionamento alimentare mondiale ma la sua disponibilità sta giungendo al termine, dal momento che il fosforo è una risorsa non rinnovabile. Inoltre, l’accumulo di fosforo nelle acque reflue è una delle cause principali di eutrofizzazione. Ciò, in aggiunta al previsto esaurimento del fosforo, conduce alla necessità di tecnologie di rimozione e recupero dagli impianti di trattamento delle acque reflue, anche in prospettiva di un’economia circolare. Inoltre, la rimozione e la riduzione della concentrazione del fosforo dalla linea fanghi
dell’impianto di trattamento può comportare un miglioramento della rimozione del fosforo dalla linea di trattamento principale dell’impianto. Molti studi si sono focalizzati su questo argomento negli ultimi anni e nella letteratura scientifica sono disponibili molti metodi legati alla rimozione e al recupero del fosforo. Questi studi includono
metodi biologici e chimici e sono stati realizzati molti impianti pilota sperimentali per testare le migliori configurazioni impiantistiche, sia da un punto di vista economico che operativo. In alcuni casi il prodotto della precipitazione chimica può essere riutilizzato in agricoltura, come nel caso della struvite e dell’idrossiapatite che possono essere utilizzati come fertilizzanti a lento rilascio. Sia la formazione della struvite che quella dell’idrossiapatite avvengono in base a determinati valori di pH e di concentrazione dei reagenti ed entrambe richiedono precise condizioni di equilibrio chimico. In accordo con la Strategia Nazionale di Specializzazione Intelligente (SNSI), il tema
della ricerca, finanziato dal Ministero dell'Università e della Ricerca (MUR) attraverso il Programma Operativo Nazionale "Ricerca e Innovazione 2014-2020" (borsa di dottorato, grant number DOT130UZWT n. 2), consiste nel considerare il mondo della depurazione dell'acqua come una "Fabbrica Intelligente ". Dopo l’analisi dei metodi di recupero e rimozione del fosforo attualmente presenti nella letteratura scientifica è stato indagato il recupero di fosforo, in forma di struvite ed idrossiapatite, dal centrato dell’impianto di trattamento delle acque reflue municipali
del Comune di Andria, a diversi pH e diverse concentrazioni di reagenti. Le analisi sono state effettuate sia per via fisica che informatica (mediante il software Visual MINTEQ) ed hanno condotto a risultati comparabili tra loro.
Il miglior risultato riscontrato al termine della campagna sperimentale ha evidenziato un recupero massimo di P dell' 87.3% che ha portato ad una quantità stimata annua di 92,0 tonnellate e 33,2 tonnellate di struvite e idrossiapatite, rispettivamente, recuperati dall’impianto di depurazione di Andria. Da una stima economica dei costi dei reagenti, il loro consumo è risultato essere circa la metà del valore di mercato del fosforo. Testando il metodo su altri impianti di depurazione ed effettuando una analisi dei potenziali impatti ambientali (Life Cycle Assessment) si potrebbe giungere ad un'applicazione del metodo su larga scala.Phosphorous (P) is a key element in the global food supply but its availability is coming to an end, because P is a non-renewable resource. Furthermore, the accumulation of phosphorous in the wastewater is one of the main causes of eutrophication. This, in addition to P depletion, leads to the need to adopt technologies to remove and recover P from the wastewater treatment plants (WWTP), also in a circular economy perspective. Specifically, the removal and recovery of P concentration from the sludge line of WWTP may result into an improvement in the P removal from the
mainstream of WWTP. Many studies have been focused on this topic in the last years and many methods linked to both P removal and recovery are available in the scientific literature. These include biological- and chemical-based technologies and many experimental pilot plants have been realized to test the best plant configuration also
from an economic and operational point of view. In some cases, the products of the chemical precipitation could be reused in agriculture, as in the case of the struvite and hydroxyapatite that can be used as slow-release fertilizers. Both struvite and hydroxyapatite precipitation take place according to determinate pH values and reagents kinds
and doses. According to the National Strategy of Intelligent Specialization (SNSI), the theme of research, financed by the Italian Ministry of University and Research (MUR) through the National Operational Programme "Research and Innovation 2014- 2020" (PhD fellowship, grant number DOT130UZWT n. 2), consists in looking at the water purification world as a "Smart Factory". After the analysis of P removal and recovery methods currently present in scientific literature, P recovery in form of struvite and hydroxyapatite from the centrate deriving from a centrifuge of the WWTP of Andria Municipality was investigated at varying pH values and reagents kinds and concentrations. The analyses were carried out both physically and informatic (using the Visual MINTEQ software) and led to comparable
results. The best result found at the end of the experimental campaign highlighted a maximum P recovery of 87.3% leading to an estimated quantity of 92.0 tons/years and 33.2 tons/years of struvite and hydroxyapatite, respectively, recovered from the WWTP of Andria. By an economic estimation of the reagent costs, the consumption of them is
almost 50% of the mean P market value. Testing the method on other WWTP and carrying out an analysis of the potential environmental impacts (Life Cycle Assessment) could lead to a large-scale application of the method
The Circulation of Mercury in the Italian economy
No full textMercury has been a metal with a very significant role in many production cycles (such as chlor-alkali industry), and, despite its toxicity, it continues to have a great importance.
On the contrary, the content of mercury in many common commodities (batteries, dental amalgams, lighting, electrical and electronics equipment and others) is very high. This exposes the population to enormous risks due to the chemical and physical characteristics of this metal.
Mercury could be considered a global pollutant: it can be easily transported over great distances by air flows and its residence time in the atmosphere is about one year: this is a long time during which mercury can circulate all around the world several times.
The reason of this is the chemical feature of the mercury in atmosphere (more than 90% is represented by elemental gaseous form Hg0, slightly soluble and relatively inert). In addition, after its oxidation to divalent mercury HgII, part of this metal enters the soil and surface water. From here, a low part of it can be reduced to the volatile elemental form that is emitted into the atmosphere once again (the so-called re-emission). The third atmospheric form of mercury is the Hgpart, in which the metal is associated to particulate, often emitted by combustion industries and power plants.
The entire bio-geo-chemical cycle of mercury demonstrates its danger. Despite of enormous damages produced by this metal and the many legislative measures to limit the mercury content in several goods, the direct emissions and the indirect ones (due to fossil fuel combustion) recorded in some countries, as China and India, are increasing.
The aim of this note is to identify the flows of this metal related to its circulation in Italy, in order to describe the amount of mercury contained in commodities and its use in industry
Physical activity for coronary heart disease: cardioprotective mechanisms and effects on prognosis
No full textAbstract: A sedentary lifestyle is one of the five major risk factors for coronary heart disease (CHD) along with hypertension, abnormal values of blood lipids, smoking and obesity. After an acute myocardial infarction, risk factors continue to contribute synergically to the clinical progression and prognosis of CHD. Regular physical exercise has been shown to improve exercise capacity and quality of life, to reduce symptoms and to decrease the risk of new coronary events in patients with CHD. Regular physical activity with its favourable effects on coronary risk factors, endothelial dysfunction, inflammation, tendency to thrombosis, on autonomic tone and myocardial ischemia, may play a role in reducing the risk of new coronary events and death. In view of the clinical benefits yielded and its well-documented cardioprotective mechanisms, regular physical activity should be regarded, by general practitioners and cardiologists, as a true and effective form of therapy for patients with CHD
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
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