1,721,093 research outputs found
Susceptibility of plastic packages to insect pests attacks
No full textPackaging represents the ultimate defence of pasta producers against insect pests; even if the product comes out uncontaminated from the production line, this does not guarantee that it will reach the consumer in the same condition. The ability of some pests to pierce different plastic material is well known: insects are attracted by odors, therefore it is necessary to take in consideration the barrier properties to volatile compounds, Pasta packages are characterized by numerous pinholes which are mechanically produced to avoid having swollen bags after sealing: these pre-existing holes are often exploited by most pests as a preferential entrance to packages, and they are detected by insects by following the outflow of attractive odors. Packaging, therefore, represents a critical point in the quality preservation of packed pasta. Insect pests are commonly present in the production and storage environments, and their presence is favoured by unappropriate prevention measures. Common pests that affect pasta and starchy products usually belong to the genera: Tribolium, Sitophilus, Plodia and Rhyzopenha. The aim of the study was to evaluate the resistance to piercing of three plastic materials (polypropylene obtained with different processing techniques) by Tribolium spp>, Sitophilus spp, and Rhyzoperíha Dominica, and the relative ability of each pest to enter the packages. Two tests were carried out, the first one was aimed at evaluating the resistance of the plastic materials, the latter evaluated the ability of the species tested to enter pasta bags. Results confirmed the good resistance of PP to the penetration of insect pests, and highlighted the highest penetration ability of Sitophilus spp. The optimization and suitable design of the packaging system, which should consider the reduction of the hole diameter, would allow to reduce the risk of pests penetration
Extended through-short-delay tecnique for the calibration ofvector network analyzers with nonmating waveguide ports
No full textOrthomode Transducer for Millimeter-Wave Correlation Receivers
No full textThis paper presents a novel orthomode-transducer (OMT) architecture,which is particularly suitable for correlation receivers at millimeter waves. By exploiting an on-axis reverse-coupling structure, a compact OMT configuration is obtained, which provides high levels of channel equalization. The Ka-band prototypes exhibit very good electric performances in terms of isolation, cross-polarization, return loss, and channel equalizatio
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
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