Flavour profile of capers (Capparis spinosa L.) from the Eolian Archipelago by HS-SPME/GC–MS

This paper presents the first investigation of the flavour profile of capers (Capparis spinosa L.) from the Eolian Archipelago. In all, 145 volatile compounds were identified and quantified in capers, by HS-SPME/GC–MS analysis. Aldehydes (22.2%) and esters (21%) were the most abundant chemical classes; five sesquiterpenes and ten monoterpenes were identified for the first time; among sulphur compounds (8.42%), methyl-isothiocyanate was the major one, followed by benzyl-isothiocyanate. The application of this solvent-free extraction technique combined with the GC–MS analysis, showed its potential as a simple routine method for analyzing food flavour.     

A Review on Agri-food Supply Chain Traceability by Means of RFID Technology

Radio Frequency Identification (RFID) is a technology which provides appealing opportunities to improve the management of information flow within the supply chain and security in the agri-food sector. Nowadays, food safety is considered a major requirement in several countries, in particular, the traceability of food products which is mandatory by law. Thus, technological implementation leading to traceability strengthening in the agri-food sector is crucial. The first aim of this review is to analyze the current developments in RFID technology in the agri-food sector, through an operative framework which organizes the literature and facilitate a quick content analysis identifying future research direction. RFID technology seems to be able to bring great opportunities to this sector; nevertheless, several constraints are slowing its adoption. This survey may provide readers with an exhaustive overview of opportunities and constraints for the wide adoption of RFID. The second aim of this review is to provide an updated analysis on the current developments of RFID technology for different product typologies within the agri-food industry, discussing at the same time its potential in technological and logistical development regarding different sectors of the production/distribution chain. As referenced here, RFID implementations in the agri-food sector are increasing at a fast rate, and technological advancement follows the applicability opportunities. However, real applications of RFID technologies are still limited because of various technical and economical obstacles which are also discussed.     

Technology up date and new strategies on fuel cells

This paper reports the state of art on fuel cells technology, outlines the most significant results reached all over the world and summarises the strategies developed by researchers and producers to get the commercialisation of these systems. In particular, the authors have examined three potential application fields for fuel cells: (i) stationary power plant for electricity production; (ii) portable power applications; (iii) electric vehicles.

The potential market area for each sector of application has been defined and the research activity necessary to overcome the technical problems that are still open have been detailed. The significant projects of main fuel cells producers are also mentioned.     

Performance and life-time behaviour of NiCu–CGO anodes for the direct electro-oxidation of methane in IT-SOFCs

An anodic cermet of NiCu alloy and gadolinia doped ceria has been investigated for CH₄ electro-oxidation in IT-SOFCs. Polarization curves have been recorded in the temperature range from 650 to 800 °C. A maximum power density of 320 mW cm⁻² at 800 °C has been obtained in the presence of dry methane in an electrolyte-supported cell. The electrochemical behaviour during 1300 h operation in dry methane and in the presence of redox-cycles has been investigated at 750 °C; variation of the electrochemical properties during these experiments have been interpreted in terms of anode morphology modifications. The methane cracking process at the anode catalyst has been investigated by analysing the oxidative stripping of deposited carbon species.     

Optical design of a high-spatial-resolution extreme-ultraviolet spectroheliograph for the transition region

A spectroheliograph dedicated to the observation of the solar disk in the extreme-ultraviolet OV spectral line at 62.97 nm is described. As demonstrated in the Skylab SO-82A spectroheliograph [Appl. Opt. 16, 870 (1977)], this line is uniquely suited to characterize solar plasma in the important 250, 000 K temperature regime. No multilayer coating or suitable filter is yet available to select this wavelength, so an optical design based on a double spectrograph with a spatial filter to remove the unwanted radiation has been developed. Analysis of the optical design shows that this instrument can obtain a 1 arcsec spatial resolution (two pixels) with a relatively high image-acquisition cadence. A preliminary tolerance analysis has been performed. A simple method of instrument alignment in visible light is also described.     

Reactions of Polyfluorobenzenes With Nucleophilic Reagents

Nucleophilic reactions of hexafluorobenzene and related polyfluorobenzenes were studied in detail. Reaction of hexafluorobenzene with hydroxides, alcoholates, aqueous amines, and organolithium compounds led to the substitution of one or more fluorine atoms. The structures of the products were determined, using near infrared and nuclear magnetic resonance spectra. Fluorine is replaced more readily than chlorine, bromine, iodine, or other groups. In the majority of the products in which two of the fluorines in hexafluorobenzene were replaced, the substituting groups were para to each other. However, depending on the reagents other orientation effects were noted. The reaction mechanisms were a function of reagents and conditions. The most prevalent mechanism is presumably the displacement of a fluoride anion by another anion, probably via the formation of transition complexes of different lifetimes. However, simple ionization or attack by neutral species may occur under some conditions. The diazotization and oxidation of pentafluoroaniline were also investigated.     

Processi di Markoff del primo ordine derivanti da processi di Markoff di ordine superiore

Sommario Si studia quando un processo di Markoff del primo ordine si può considerare derivato da un processo di markoff di ordine superiore a uno. Ciò viene fatto essenzialmente utilizzando la nozione di grafo associato ad un processo di Markoff.

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Summary We study when a process of Markoff of the first order may be considered derived from a process of Markoff of higher order. This is obtained by using the notion of graph associated to a process of Markoff.

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Lavoro eseguito nell'ambito dell'attività del G.N.S.A.G.A. e del G.N.A.F.A. del Comitato per le Scienze Matematiche del C.N.R.     

Satisfaction with social networks: An examination of socioemotional selectivity theory across cohorts.

This study examines L. L. Carstensen's (see records 1993-98639-005 and 1996-22608-001) socioemotional selectivity theory within and across three cohorts spanning 4 decades. Socioemotional selectivity theory predicts that as individuals age, they narrow their social networks to devote more emotional resources to fewer relationships with close friends and family. Data from 3 cohorts of nationally representative samples were analyzed to determine whether respondents' satisfaction with the size of their social networks differed by age, cohort, or both. Results support socioemotional selectivity theory: More older adults than younger adults were satisfied with the current size of their social networks rather than wanting larger networks. These findings are consistent across all cohorts. Results are discussed with respect to social relationships across the life course. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kinetics of acetone hydrogenation over Pt/Al2O3 catalysts

The hydrogenation of acetone to isopropanol has been studied in the vapour phase over Pt/Al₂O₃ catalysts. The rate law obtained at a total pressure of 1 atm and temperatures between 303 and 363 K is of the form V=kP⁰_aP^1/2_H exp (-44 kJ mol^?1 RT^?1). The kinetic results are consistent with a Langmuir-Hinshelwood hydrogenation mechanism involving a half hydrogenated species and a non-competitive chemisorption of acetone and hydrogen on the platinum surface. The specific activity (calculated per platinum surface atom) has been found to be scarcely dependent on the platinum particle size. It is suggested that the chemisorption sites are made of a very small ensemble of platinum atoms.     

Mechanism of O2 evolution on TiO2 photoanodes

The mechanism of O₂ evolution over titanium oxide photoanodes has been studied by relating structural properties, derived from XRD and XPS, and electrochemical properties currents, (cyclic voltammetry and flatband potentials) to the performance in PEC cells of five specimens of lowest and highest photoelectrochemical efficiency.