518 research outputs found
FUEL-BASED POLLUTANTS REMOVAL FROM WATER: STRUCTURAL EVIDENCES OF ADSORPTION INTO HIGH SILICA ZEOLITES
No full textThe enormous and rapid development of the chemical and agrochemical industries during the last century has resulted in the release of a large number of chemical compounds into the environment. Aquatic ecosystems are especially vulnerable because water bodies are frequently used, directly or indirectly, as recipients of potentially toxic liquids and solids from domestic, agricultural and industrial wastes. Removal of fuel-based compounds from natural water is of considerable interest due to the harmful effects of these pollutants on the environment, even at very low concentration [1]. Among this category of compounds, toluene, 1,2-dichloethane and methyl-tert-buthyl-ether are of special relevance since are toxic and commonly found in natural water. Research on hydrocarbon removal has been mainly focussed on single components from air matrix, whereas the studies involving aqueous dilute solutions are few [2-5]. Adsorption is a reliable alternative to eliminate these organic compounds from wastewaters because of the flexibility of the system, low energy and cheap operation costs. Moreover, the process does not induce the formation of oxidation intermediates which are, to date, mostly unknown. The presence of natural organic matter can significantly affect organic pollutant adsorption by either competing for adsorption sites, or restricting access to (micro)pores.
This work is a part of a wider project whose purpose is to study the interaction and mobility of ground water pollutants adsorbed in the zeolites pores. Organophilic synthetic zeolites which are cheap and available on the market, differing in topology, channel systems and free window apertures, and fuel-based-pollutants differing in chemical properties and molecular dimensions, were tested. In particular, structural evidences of adsorption from dilute solutions into organophilic zeolite as well as the competitive role of humic acid monomers, the effect of the temperature in the adsorption processes will be discussed. The selected adsorbents were commercial as-synthesized hydrophobic ZSM-5 and Y zeolites with high SiO2/Al2O3. Kinetics and adsorption isotherm batch data were obtained via Headspace Solid Phase Microextraction-GC. X-ray powders patterns were collected before and after adsorption on a Bruker D8 Advance diffractometer equipped with SOL-X detector. Thermal analyses (TG and DTA) were performed in air up to 900°C at 10°C/min. Infrared spectra were collected on a Thermo Electron Corporation FT Nicolet 5700 Spectrometer. This combined diffractometric, thermogravimetric, chromatographic and spectroscopic study allowed us to: 1) measure the sorption capacity of hydrophobic zeolite materials weighed against organic pollutants dissolved in water; 2) characterise the structure after contaminants adsorption; 3) localise the organic species in the zeolite channel systems; 4) highlight the role of humic acid monomers in the pollutants removal; 5) probe the interaction between the adsorbate and the zeolite framework. The very favorable adsorption kinetics along with the effective and highly irreversible adsorption into zeolite pores make these cheap and environmental friendly materials applicable for the treatment of water contaminated with fuel-based pollutants.
References. [1] Trindade P.V.O., Sobral L.G. , Rizzo A.C.L., Leite S.G.F. (2005) Chemosphere, 58, 515–522; [2] L.Abu-Lail, J. A. Bergendahl, R. W. Thompson, Journal of Hazardous Materials 2010, 178, 363-369. [3] Martucci A., Pasti L., Nassi M., Alberti A., Arletti R., Bagatin R., Vignola R., Sticca, R. (2012) Micropor. Mesopor. Mater. 148, 174-183. [4] Arletti, R., Martucci, A., Alberti, A., Pasti, L., Nassi, M., Bagatin, R. (2012) Journal of Solid State Chemistry, 194, 135-142.[5] Pasti L., Martucci A., Nassi M., Cavazzini A., Alberti A., Bagatin, R. (2012) Microporous and Mesoporous Materials, 160, 182-193
Consenso informato e tradizione islamica. Confronto culturale e legislativo a fini medico-legali.
No full textThe Arabic Manuscripts on Grammar from the Kahle Fonds: Some Research Proposals
No full textThe Paul Kahle Fonds, preserved at the University of Turin, gather together printed books,
manuscripts and papers related to the activities of Paul Ernst Kahle (1875-1964) as an orientalist scholar. In the
Islamic manuscripts section, a big number of them deal with the Arabic grammar tradition. Most of the works
included in the manuscripts date back to the post-classical age (from XI to XIX century), with a particular
concentration in the XIV century. Almost all the works are commentaries of first or second order to previous
treatises by well known grammarians. From a point of view both chronological and structural, these works can
be placed in the pedagogic stage of the Arabic grammar tradition, characterized by a change in the organisation
of the topics and in the way topics relating to syntax or morphology were dealt with. On the basis of two main
perspectives, some clusters are identifiable to illustrate the different relations one can recognize between the
original independent treatises and their commentaries or between commentaries of the same/different order. In
such a way, scholars are also allowed to check for possible and more complex inter-text relationships, to
highlight mutual influences among authors and/or commentators, to investigate topics or methods peculiar to one
author/commentator and to follow up their developments
From ʿilm al-naḥw to maʿānī l-naḥw in ʿAbd al-Qāhir al-Ǧurǧānī’s linguistic thinking
No full textʿAbd al-Qāhir al-Ǧurǧānī (d. 471/1078) is today known for being the author of two fundamental treatises: Dalāʾil al- ʾiʿǧāz and ʾAsrār al-balāġa. The first one is about ʿilm al-maʿānī, a discipline labelled by some modern scholars as “syntax semantics”, “grammatical semantics”, “syntax stylistics” and even as “functional grammar”. The second treatise is about the study of rhetoric (ʿilm al-balāġa). However, most of Ǧurǧānī’s works are about grammar (naḥw), dealing with topics such as grammatical operativity (ʿamal), desinential inflection (ʾiʿrāb), noun and verb morphology, etc. As a rule, ancient and modern scholars have kept separate the two methods of his linguistic thinking: the descriptive and at times pedagogical approach; and the theoretical, semantic-oriented approach, concerning which Ǧurǧānī is acknowledged among the pioneers. Thus, his works would have been addressed to various kinds of readers and have known a different fortune depending on the time, the geographical area and the cultural environment of their reception. It is, however, possible to suppose a continuity in Ǧurǧānī’s linguistic thinking connecting the two groups of works. Following this line of enquiry, one is supposed to find in his grammatical dissertations the seeds of what would have become his “theory of meaning” within the Dalāʾil al-ʾiʿǧāz
High-reliability fault tolerant digital systems in nanometric technologies: Characterization and design methodologies
No full textThis paper reports the main contribution of a project devoted to the definition of techniques to design and evaluate fault tolerant systems implemented using the SoPC paradigm, suitable for missionand safety-critical application environments. In particular, the effort of the five involved research units has been devoted to address some of the main issues related to the specific technological aspects introduced by these flexible platforms. The overall target of the research is the development of a design methodology for highly reliable systems realized on reconfigurable platforms based on a System-on-Programmable Chip (SoPC), as discussed in the next sectio
The Arabic Manuscripts on Grammar from the Kahle Fonds: Some Research Proposals
No full textThe Paul Kahle Fonds, preserved at the University of Turin, gather together printed books, manuscripts and papers related to the activities of Paul Ernst Kahle (1875-1964) as an orientalist scholar. In the Islamic manuscripts section, a big number of them deal with the Arabic grammar tradition. Most of the works included in the manuscripts date back to the post-classical age (from XI to XIX century), with a particular concentration in the XIV century. Almost all the works are commentaries of first or second order to previous treatises by well known grammarians. From a point of view both chronological and structural, these works can be placed in the pedagogic stage of the Arabic grammar tradition, characterized by a change in the organisation of the topics and in the way topics relating to syntax or morphology were dealt with. On the basis of two main perspectives, some clusters are identifiable to illustrate the different relations one can recognize between the original independent treatises and their commentaries or between commentaries of the same/different order. In such a way, scholars are also allowed to check for possible and more complex inter-text relationships, to highlight mutual influences among authors and/or commentators, to investigate topics or methods peculiar to one author/commentator and to follow up their developments
Il Mi’at ‘āmil fī an-naḥw di ‘Abd al-Qāhir al-Ğurğānī. Un trattato didattico sugli operanti grammaticali in arabo
No full textIl volume contiene un'edizione critica del breve trattato di ‘Abd al-Qāhir al-Ğurğānī sugli operanti grammaticali intitolato Mi’at ‘āmil fī an-naḥw (Centro operanti grammaticali).The so-called theory of grammatical opertors represents one of the cornerstones of the Arabic grammatical tradition, a fundamental chapter in the works of the classical age and the following centuries. Through it, the grammarians explained what was to them the distinctive feature of their language model, that is, the inflection of nouns and verbs. The Mi’at ‘āmil fī an-naḥw (One Hundred Grammatical Operators) by ‘Abd al-Qāhir al-Ğurğānī is a short treatise of the 11th century which aims to provide a classification of such operators, enriched by some semantic clarifications. It is considered one of the first treatises of the “pedagogical phase” of the Arabic grammatical tradition, and among the most commented by the subsequent grammarians. From a linguistic point of view, the relevance of the work arises in so far as it is integrated with the other grammatical treatises of the same author. In this way, it is possible to grasp the theoretical approach given to the operativeness issue, and reflect on the relationship between syntax and meaning, whose full formulation would have appeared in the theory of speech as we find it in the semantic-rhetorical works, for which al-Ğurğānī is above all known today
A new linear amplifier for the RFX electron energy analyzer
No full textA simple low cost novel linear amplifier has been developed for the electron energy analyzer employed on the reversed field pinch experiment RFX. The amplifier is designed to provide a 1 kV output voltage from a 10 V input. The current rating is ± 50 mA. It utilizes a configuration of four blocks in series, each of them with an output totem-pole configuration. The rise and fall times are of a few milliseconds. A fast protection against output short circuit has been implemented. The amplifier has been used in various experimental campaigns on RFX and multiple time resolved measurements of the edge electron energy distribution in a single plasma discharge have been obtained
The power supply system for Langmuir probes on RFX
No full textA power supply system for Langmuir probes to be used on the reversed field pinch (RFP) thermonuclear fusion experiment RFX has been developed. It is based on a full-bridge converter concept, using a pulse width modulation (PWM) technique, and is characterized by a 5 A, ±150 V rating. The power supply has been designed to ensure compatibility with the electromagnetic noise close to the machine and with the plasma, which behaves as a nonlinear rapidly varying load. The system has been optimized by numerical simulations. Tests in the laboratory and on the experiment have been performed in a wide range of working conditions, and the system has been proven to suit fairly well the RFX experimental conditions
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