Ionic liquids as diathermic fluids for solar trough collectors’ technology: A corrosion study

The AISI 304 and AISI 1018 steels (frequently used in solar collectors’ plants) in contact with four different ionic liquids (ILs) suitable as diathermic fluids, were studied. Immersion tests were performed at 220 °C (the working temperature in such plants) for 10 days. The corrosion morphologies of the steels were investigated by scanning electron microscopy coupled with energy dispersive X-ray (EDX) microanalysis and the content of metals in the solution were detected via ICP-OES. The tests showed that the most performing IL is the ethyl-dimethyl-propyl-ammonium-bis(trifluoromethylsulphonyl)imide. The corrosion properties of the two alloys in contact with such IL were investigated by means of Tafel plots and resistance polarization at room temperature in open-to-air vessels.     

Effective wind actions on ideal and real structures

Gust buffeting of structures is analyzed by Double Modal Transformation, a method consisting in the joint transformation into principal components of structural displacements (modal analysis) and of wind loading (proper orthogonal decomposition). It commonly occurs that modal truncation applies to both the series of structural and loading modes; besides, many loading modes are almost orthogonal respect the dominant structural modes, so they do not contribute to structural response. This set of conditions allows the introduction of an effective action, defined as the loading process reconstructed retaining only those loading modes that excite the structure. This paper discusses this method and the related concepts by analyzing a set of simple ideal structures in closed form; this approach allows the formulation of general criteria aimed at defining the effective wind action as a function of non-dimensional structural and wind parameters. The numerical analysis of a real structure confirms the tendencies pointed out by the analytical solutions.     

Soft-Seeded Pomegranate (<Emphasis Type="Italic">Punica granatum</Emphasis> L.) Varieties: Preliminary Characterization and Quality Changes of Minimally Processed Arils During Storage

A preliminary characterization of two new soft-seeded pomegranate varieties (MR-100® and KINGDOM®) based on their main physico-chemical and nutritional parameters was reported. The two varieties showed significant differences (p ≤ 0.05) in polyphenols, anthocyanins and antioxidant activity. Kingdom pomegranate had higher polyphenols (2524.73 mg GAE/L), anthocyanins (752.49 mg C₃gE/L) and antioxidant activity (EC₅₀ 13.58 μL/mL) than MR-100 (1792.74 mg GAE/L, 141.29 mg C₃gE/L and EC₅₀ 47.53 μL/mL, respectively). Moreover, minimally processed arils of the two varieties were packaged in semipermeable and micro-perforated film at 5 °C, and the quality changes that occurred during storage condition (15 days) were investigated. During storage, Kingdom arils exhibited a better performance in terms of antioxidant activity, polyphenols and anthocyanin content with respect to MR-100. Furthermore, the packaging systems did not affect the estimated quality parameters for both varieties. Based on the sensory evaluation and microbial counts, both aril varieties reached, at 15-day storage, suitable values for commercial purpose.     

An experimental and kinetic modeling study of cyclopentadiene pyrolysis: First growth of polycyclic aromatic hydrocarbons

The importance of 1,3-cyclopentadiene (CPD) and cyclopentadienyl (CPDyl) moieties in the growth of polycyclic aromatic hydrocarbons (PAHs) was studied using new experimental data and ab initio calculations. The experimental investigation was performed in a tubular continuous flow pyrolysis reactor under both high (24molN₂/molCPD)$(24{\text{mol}}_{{\text{N}}_2}/{\text{mol}}_{\text{CPD}})$ and low (5molN₂/molCPD)$(5{\text{mol}}_{{\text{N}}_2}/{\text{mol}}_{\text{CPD}})$ nitrogen dilutions, covering a temperature range of 873–1123 K, at a fixed pressure of 1.7 bara. At the most severe conditions up to 84% of CPD is converted, and the amount of PAHs is more than 65 wt%. Major products observed during CPD pyrolysis were benzene, indene, methyl-indenes and naphthalene, in line with previous studies. On-line GC × GC-FID/(TOF-MS) also allowed to quantify minor species (methane, toluene, styrene, phenanthrene, anthracene, etc.), never reported before at this level of accuracy. The new experimental data have been used to further analyze the role of the successive interactions of CPD, indene, and naphthalene as well as the recombination and addition reactions of their resonantly stabilized radicals and refine their kinetics. The results of the modeling study are in good agreement with existing and new experimental observations.     

IRS-III: A broker-based approach to semantic Web services

A factor limiting the take up of Web services is that all tasks associated with the creation of an application, for example, finding, composing, and resolving mismatches between Web services have to be carried out by a software developer. Semantic Web services is a combination of semantic Web and Web service technologies that promise to alleviate these problems. In this paper we describe IRS-III, a framework for creating and executing semantic Web services, which takes a semantic broker-based approach to mediating between service requesters and service providers. We describe the overall approach and the components of IRS-III from an ontological and architectural viewpoint. We then illustrate our approach through an application in the eGovernment domain.     

Bisorbicillinoids Produced by the Fungus <Emphasis Type="Italic">Trichoderma citrinoviride</Emphasis> Affect Feeding Preference of the Aphid <Emphasis Type="Italic">Schizaphis graminum</Emphasis>

We report the effects of some bisorbicillinoids isolated from biomass of the fungus Trichoderma citrinoviride on settling and feeding preference of the aphid Schizaphis graminum. Purification of the fungal metabolites was carried out by a combination of column chromatography and thin-layer chromatography using direct and reverse phases. Chemical identification was performed by spectroscopic methods including nuclear magnetic resonance and mass spectrometry. The identified bisorbicillinoids appeared to be bislongiquinolide, its 16,17-dihydro derivative, trichodimerol, and dihydrotrichodimerol. A feeding preference test with alate morphs of S. graminum was used to identify the active fractions. Among the four bisorbicillinoids, dihydrotrichodimerol and bislongiquinolide influenced aphid feeding preference, restraining specimens from settling on leaves treated with metabolites. Taste neurons sensitive to these compounds, particularly to bislongiquinolide, were located on tarsi of the S. graminum alate morphs.     

Traffic analysis of peer-to-peer IPTV communities

The Internet is currently experiencing one of the most important challenges in terms of content distribution since its first uses as a medium for content delivery: users from passive downloaders and browsers are moving towards content producers and publishers. They often distribute and retrieve multimedia contents establishing network communities. This is the case of peer-to-peer IPTV communities.In this work we present a detailed study of P2P IPTV traffic, providing useful insights on both transport- and packet-level properties as well as on the behavior of the peers inside the network. In particular, we provide novel results on the (i) ports and protocols used; (ii) differences between signaling and video traffic; (iii) behavior of the traffic at different time scales; (iv) differences between TCP and UDP traffic; (v) traffic generated and received by peers; (vi) peers neighborhood and session duration. The knowledge gained thanks to this analysis is useful for several tasks, e.g. traffic identification, understanding the performance of different P2P IPTV technologies and the impact of such traffic on network nodes and links, and building more realistic models for simulations.¹     

A study of heat distribution and dissipation in a micromachined chemoresistive gas sensor

A micromachined chemoresistive gas sensor was studied from the point of view of heat distribution and thermal dissipation: this innovative device for environmental pollutant gas monitoring, is based on a sensitive film of semiconductor metal oxides, kept in temperature by a platinum resistor. In order to avoid electrical interactions between the film heater and the contacts for the film reading, the heater is driven by a square wave, and the film is read when no voltage is provided. Since the working temperature of the film is extremely important for its operation, it is crucial to maintain the temperature fluctuations within few degrees; to this end, in this work we study the heat distribution and dissipation of such a device, aiming to set a proper heating frequency, which will assure a right stability of the working temperature.