Papers by Pacifico Cofrancesco
IFAC Proceedings Volumes, Nov 1, 1989
In this paper a software production methodology for process control is presented. The specificati... more In this paper a software production methodology for process control is presented. The specification phase is carri e d out by resorting to the formalism of Petri Nets. By means of a worked example it is shown how Petri Nets are amenable to describe feedback control structures. The implementation of Petri Net models is performed by the use of a data driven architecture. The presence of system tasks supplying standard functions, such as monitor, display, command acquisition is also considered to ease software production.
Ball-milled Mg – Ni – Cu mixtures: phase analysis and sorption performances
ACTA IMEKO
A recent finding at the Castello Sforzesco in Milan of two brass natural horns from the end of th... more A recent finding at the Castello Sforzesco in Milan of two brass natural horns from the end of the 17th century and assigned to the Haas family from Nuremberg brought to light new information about this class of objects. The instruments were heavily damaged, but their historical value was great. In this study, a multidisciplinary approach mainly based on non-invasive analytical techniques and including X-rays investigations (X-ray radiography, X-ray fluorescence and X-ray diffraction) was used. The present study was aimed at: i) pointing out the executive techniques for archaeometric purposes; ii) characterizing the morphological and the chemical features of materials; and iii) identifying and mapping the damages of the structure and the alterations of the surface.
Hydrogen storage in magnesium-metal mixtures: reversibility, kinetic aspects and phase analysis, orage in magnesium – metal mixtures
Elsevier, 2008
The sorption capacity and kinetics of mechanically activated binary mixtures of Mg with nine diff... more The sorption capacity and kinetics of mechanically activated binary mixtures of Mg with nine different metals (Al, Cu, Fe, Mn, Mo, Sn, Ti, Zn, Zr) have been studied to determine whether these metals act as catalyzing/destabilizing agents in formation/decomposition of Mg hydrides. Identification of crystalline phases before and after the absorption/desorption processes assists our understanding of the different behaviors displayed
A new NMR duplexer made with quadrature couplers
Measurement Science and Technology, 1991
A new type of duplexer is presented which employs two 90 degrees couplers. It is an ideally lossl... more A new type of duplexer is presented which employs two 90 degrees couplers. It is an ideally lossless device, with an attenuation of about 1 dB in both receiving and high power (>50 dBm) transmitting modes, and with a transmitter-receiver isolation better than 40 dB. The authors describe two duplexers built with multi-octave couplers, covering the frequency ranges 30-90 MHz and 90-500 MHz, respectively. These broadband devices are conveniently employed in high RF-power, multinuclear NMR spectrometers.
Alteration processes of pigments exposed to acetic and formic acid vapors
2017 IEEE International Conference on Environment and Electrical Engineering and 2017 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2017
This contribution investigates the chemical modifications experienced by different historic inorg... more This contribution investigates the chemical modifications experienced by different historic inorganic pigments when exposed to acetic and formic acid vapors naturally produced by wood. The production of acetic and formic acid vapors by wood is well known phenomenon; their interactions with different materials as metals, limestone or glass were already investigated, but only few researches concern interactions with pigments. Pigments modification processes represent one of the most important causes of artworks deterioration since they are directly involved in the pictorial films and their colors. Polychromatic artworks, such as paintings or manuscripts, are generally held indoor where they could be directly exposed to the acid vapors produced by wood floors or cases. In order to study the interactions between pigments and acid vapors, Azurite, Red Lead, Tin-Lead Yellow, and White Lead pigments were selected on the basis of their chemical composition and historical wide use. Powders of these materials were exposed in a simulated acetic and formic acid environments and their alteration processes were investigated by XRD and SEM analyses. The assessment of chromatic variations was performed through a colorimeter.
Analysis and characterization of ancient mortars of the Medio Volturno River area
Within the framework of an archaeological and historical survey of some Medieval and a few Roman ... more Within the framework of an archaeological and historical survey of some Medieval and a few Roman buildings of the Medio Volturno River area (in the Italian regions of Molise and Campania) conducted by the Laboratorio di Archeologia Tardoantica e Medievale (LATEM) of the University Suor Orsola Benincasa of Naples, we analyzed and characterized the samples of ancient mortars of about 25 historical sites of the area, dating from the 1 st century B.C. to the the 14th century A.D., taken from several different kinds of buildings, with civil, religious, and military uses. The physico-chemical characterization of the mortars was carried out by XRPD with Rietveld refinement, for the quantitative determination of their mineralogical compositions, with subsequent validation by SEM/EDS. Moreover, TGA were performed to determine the water content of the mortars, and microscopic thin sections analyses were made to obtain information about their morphological and basic physical properties. The results of the analyses were mapped by our GIS system, and compared with geological data of the area of interest to find the relation between the composition of the mortars and the typical minerals present in each area.
Microstructural investigations on historical organ pipes
Journal of Materials Science, 2017
Organs have always been among the most important musical instruments in Europe. Because of their ... more Organs have always been among the most important musical instruments in Europe. Because of their highly complex mechanical systems and the wide variety of materials they are made of, such as metal, ivory, wood or paperboard, they are considered one of the hardest instruments to preserve. Particularly, the different materials used to make the pipes, mainly tin or lead alloys, are sensitive to environmental conditions such as temperature and moisture, and consequent decay. The alteration processes are mostly due to tin-pest development or to the oxidation. As a consequence, sound quality decreases or, in the worst cases, pipes are completely lost. The aim of this work is to investigate several Italian pipe fragments dating from the seventeenth to twentieth century, in order to: (1) analyse the raw materials and the traditional manufacturing of organ pipes, in relation to conservation issues; (2) characterize the particular decay processes; (3) outline a suitable methodological approach to characterize the most common alterations of metal organ pipes. For this purpose, during the analytical campaign, both non-invasive and micro-destructive methodologies were performed, i.e. stereomicroscopy observations, X-ray fluorescence analysis, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis and X-ray diffraction. The application of the proposed analytical procedure allowed the differentiation of the pipe fragments examined into several groups on the basis of original materials and morphological characteristics.
Determination of the post mortem interval in skeletal remains by the comparative use of different physico-chemical methods: are they reliable as an alternative to 14 C?
HOMO - Journal of Comparative Human Biology, 2017
The determination of the post-mortem interval (PMI) of skeletal remains is a challenging aspect i... more The determination of the post-mortem interval (PMI) of skeletal remains is a challenging aspect in the forensic field. Previous studies focused their attention on different macroscopic and morphological aspects but a thorough and complete evaluation of the potential of chemical and physical analyses in this field of research has not been performed. In addition to luminol test and Oxford histology index (OHI) reported in a recent paper, widely spread and accessible methods based on physical aspect and chemical characteristics of skeletal remains have been investigated as potential alternatives to dating by determination of (14)C. The investigation was performed on a total of 24 archeological and forensic bone samples with known PMI, with inductively coupled plasma optical emission spectrometer (ICP-OES), inductively coupled plasma quadruple mass spectrometry (ICP-MS), Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray analysis (EDX), powder X-ray diffraction analysis (XRPD) and scanning electron microscopy (SEM). Finally, the feasibility of such alternative methods was discussed. Some results such as carbonates/phosphates ratio from FT-IR, the amounts of organic and inorganic matter by EDX, crystallite sizes with XRPD, and surface morphology obtained by SEM, showed significant trends along with PMI. Though, from a chemical point of view cut-off values and gold-standard methods still present challenges, and rather different techniques together can provide useful information toward the assessment of the PMI of skeletal remains. It is however clear that in a hypothetical flowchart those methods may be placed practically at the same level and a choice should always consider the evaluation of results by each technique, execution times and a costs/benefits relationship.
International Journal of Hydrogen Energy, 2016
Magnesium borohydride Mg(BH 4 ) 2 is a promising hydrogen storage material as it releases high hy... more Magnesium borohydride Mg(BH 4 ) 2 is a promising hydrogen storage material as it releases high hydrogen storage capacity at mild desorption temperatures, but it is still limited by slow hydrogen release kinetics and by the harsh conditions required to re-hydrogenate this compound. In this work, composites made of commercial Mg(BH 4 ) 2 and synthesized silica aerogel microparticles were prepared by thermal treatment in hydrogen under 120 bar and 200ºC. As a result, the sorption properties of the hydride are improved: calorimetric measurements show that decomposition temperature is reduced by 60ºC, and the typical 3-step decomposition mechanism of Mg(BH 4 ) 2 changes to a single-step mechanism in range of 220-400°C. The kinetics of the first dehydrogenation at 300ºC was two times faster in Mg(BH 4 ) 2 -SiO 2 composites than in the case of bulk γ-Mg(BH 4 ) 2 . Additionally, the re-hydrogenation of this material at comparatively moderate conditions of 390ºC and 110 bar is presented for the first time, achieving cyclability with a reversible release of hydrogen up to 6wt%. Different amounts of hydrogen were exchanged depending on the temperature of desorption (300ºC or 400ºC) and the presence or absence of silica aerogel. This result indicates that silica aerogel chemically interacts with Mg(BH 4 ) 2 , acting as an additive, which can result in different hydrogenationdehydrogenation routes in which different amounts and types of intermediates are formed, influencing the kinetics and the cyclability.
Fast Field Cycling Relaxometry: Applications to Paramagnetic and Superparamagnetic Systems
Properties of Glauconite/Polyaniline Composite Prepared in Aqueous Solution of Citric Acid
Journal of Polymers and the Environment, 2016
Hybrid composite made of glauconite and polyaniline was prepared in aqueous solution of citric ac... more Hybrid composite made of glauconite and polyaniline was prepared in aqueous solution of citric acid. Scanning electron microscopy combined with energy dispersive X-ray analysis shows uniform aggregates made of glauconite microparticles and polyaniline matrix. The results of X-ray powder diffraction suggest that: (1) citric acid used for the polymerisation of aniline causes formation of emeraldine salt where macromolecular ordering in the amorphous polymer takes place; (2) no chemical interaction between glauconite and emeraldine takes place in the prepared composite. FT-IR spectra of the prepared polymer and composite show features indicating all the functional groups that are present in the diiminoquinone–diaminobenzene state of polyaniline. Thermal stability of the composite was higher than the prepared polymer suggesting the occurrence of an interphase interaction between glauconite and emeraldine. After pyrolysis in purified nitrogen the composite still remained glauconite, and ε-Fe3N together with amorphous and graphitic carbon were found as reaction products. The values of electrical conductivity and magnetization of the composite suggest that optimization of these values might be achieved based upon the relationship between glauconite and polyaniline.
Technical issues of Fast Field Cycling NMR Relaxometry
Instructional Process and Digital Resources
Sintesi meccanochimica del metaniobato di litio (LiNbO3)
The huge quantity of data, media, applications, and services-in one word, resources-that are accu... more The huge quantity of data, media, applications, and services-in one word, resources-that are accumulating day after day on the Web makes it more and more difficult to search the network in an effective and helpful way. We usually spend a lot of the time trying to "filter out" what we consider "noise" added to the "good information" for which we are looking. Whatever the search domain, this messy and discouraging situation cannot be handled by general search engine, such as Google. We also face similar problems in the instructional domain. In this paper we focus on the need for creating tools that can help classifying and retrieving digital Web resources for Computer-Aided Instruction processes. We propose a strong, but simple and flexible, classification scheme, which can be easily and profitably used by a Web community (of teachers, learners, and others) to create a database of references to digital instructional resources. Our classification scheme us...
Monitorare la formazione degli studenti universitari: il caso della Facoltà di Farmacia dell’Università di Pavia
Journal of e-Learning and Knowledge Society - Italian Version, 2011
Questo lavoro descrive l’utilizzo di una piattaforma e-learning per la costruzione di un sistema ... more Questo lavoro descrive l’utilizzo di una piattaforma e-learning per la costruzione di un sistema in grado di registrare, in progress , il percorso accademico dello studente. La preparazione degli studenti all’inizio della carriera accademica e stata valutata tramite un test d’ingresso non selettivo, implementato sulla stessa piattaforma e-learning utilizzata in seguito durante il corso di studi; la progressione accademica dello studente e stata invece valutata analizzando i risultati delle prove di profitto in un insegnamento pilota, anch’esse implementate in piattaforma. L’analisi della storia dello studente (tipo di scuola, punteggio di maturita) e delle votazioni riportate ai test d’ingresso e alle prove di profitto dell’insegnamento pilota ha evidenziato l’effetto considerevole della motivazione sulla performance accademica; l’analisi delle attivita in piattaforma ha d’altra parte identificato alcuni strumenti utili ad aumentare tale motivazione. Questo lavoro prelude alla costr...
Risorse Web per didattica assistita da computer: uno schema di classificazione misto
Journal of e-Learning and Knowledge Society - Italian Version, 2011
La grande quantita di dati, media, applicazioni e servizi - in una parola, risorse - che si accum... more La grande quantita di dati, media, applicazioni e servizi - in una parola, risorse - che si accumulano giorno per giorno sul Web, rende sempre piu difficile eseguire ricerche in rete utili ed efficaci. Solitamente si perde molto tempo a cercare di "filtrare" quello che si considera "rumore", sovrapposto alle "informazioni buone" che si stanno cercando. Qualunque sia l'ambito della ricerca che stiamo svolgendo, i motori di ricerca di tipo generale, alla Google, non sono in grado di gestire questa complessa e scoraggiante situazione. Anche nel campo della didattica si ha lo stesso tipo di problemi. In questo articolo focalizziamo la nostra attenzione sulla necessita di creare degli strumenti di supporto alla catalogazione e ricerca di risorse Web utilizzabili nella didattica assistita da computer ( Computer-Aided Instruction , CAI). In particolare, proponiamo un robusto ma semplice schema di classificazione, che possa essere utilizzato in modo facile ...
Dalla Via Latina alla Francigena, ricostruzione del percorso tra Cassino e Benevento e sua pubblicazione in webGIS/cloudGIS
La recente riscoperta degli antichi cammini europei di epoca medioevale se da una parte rappresen... more La recente riscoperta degli antichi cammini europei di epoca medioevale se da una parte rappresenta una condivisibile azione culturale, dall’altra parte puo offrire ai luoghi attraversanti una notevole risonanza mediatica e di conseguenza significative ricadute economiche. Il presente contributo ha l’obiettivo di riscoprire l’antico percorso di una delle Francigene del sud, nel tratto che da Cassino conduce a Benevento, passando per la media valle del Volturno e la bassa valle del Calore. Allo stesso tempo si vuole mostrare come l’utilizzo di moderne tecnologie per la produzione di cartografia digitale interattiva, mediante GIS e successiva pubblicazione in webGIS, possa, da un lato, supportare proficuamente l’attivita d’indagine e, dall’altro, consentire al pubblico generale di Internet un facile accesso ai risultati della ricerca, mediante i moderni dispositivi di navigazione sul Web (telefoni mobili e tablet), con positivi effetti in termini di promozione turistica dei territori ...
Zn ion diffusion in spinel-type cathode materials for rechargeable batteries: the role of point defects
Materials Today Communications
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Papers by Pacifico Cofrancesco