209 research outputs found

    Review on quality assurance along the CFRP value chain - Non-destructive testing of fabrics, preforms and CFRP by HF radio wave techniques

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    Eddy current testing is well established for non-destructive testing of electrical conductive materials [1]. The development of radio frequency (RF) eddy current technology with frequency ranges up to 100 MHz made it possible to extend the classical fields of application even towards less conductive materials like CFRP [2][3](Table 2). It turns out that RF eddy current technology on CFRP generates a growing number of valuable information for comprehensive material diagnostic. Both permittivity and conductivity of CFRP influence the complex impedance measured with RF eddy current devices. The electrical conductivity contains information about fiber texture like orientations, gaps or undulations in a multilayered material. The permittivity characterization influenced by dielectric properties allows the determination of local curing defects on CFRP e.g. hot spots, thermal impacts or polymer degradation. An explanation for that effect is seen in the measurement frequency range and the capacitive structure of the carbon rovings. Using radio wave frequencies for testing, the effect of displacement currents cannot be neglected anymore. The capacitive structures formed by the carbon rovings is supposed to further strengthen the dielectric influences on eddy current measurement signal [3]. This report gives an overview of several realized applications and should be understood as a general introduction of CFRP testing by HF Radio Wave techniques

    The International Virus Bioinformatics Meeting 2023

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    The 2023 International Virus Bioinformatics Meeting was held in Valencia, Spain, from 24–26 May 2023, attracting approximately 180 participants worldwide. The primary objective of the conference was to establish a dynamic scientific environment conducive to discussion, collaboration, and the generation of novel research ideas. As the first in-person event following the SARS-CoV-2 pandemic, the meeting facilitated highly interactive exchanges among attendees. It served as a pivotal gathering for gaining insights into the current status of virus bioinformatics research and engaging with leading researchers and emerging scientists. The event comprised eight invited talks, 19 contributed talks, and 74 poster presentations across eleven sessions spanning three days. Topics covered included machine learning, bacteriophages, virus discovery, virus classification, virus visualization, viral infection, viromics, molecular epidemiology, phylodynamic analysis, RNA viruses, viral sequence analysis, viral surveillance, and metagenomics. This report provides rewritten abstracts of the presentations, a summary of the key research findings, and highlights shared during the meeting

    Collusive Effects of a Monopolist's Use of an Intermediary to Deliver to Retailers

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    A manufacturer contracting secretly with several downstream competitors faces an opportunism problem, preventing it from exerting its market power. In an infinitely repeated game, the opportunism problem can be relaxed. We show that the upstream firm's market power can be restored even further if the upstream firm chooses a mixed distribution system in which it makes use of an intermediary to distribute the good to a subset of the retailers and delivers directly only to the remaining downstream firms

    Consumer Shopping Costs as a Cause of Slotting Fees: A Rent-Shifting Mechanism

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    Analyzing a sequential bargaining framework with one retailer and two suppliers of substitutable goods, we show that slotting fees may emerge as a result of a rent-shifting mechanism when consumer shopping costs are taken into account. If consumers economize on their shopping costs by bundling their purchases, their buying decision depends rather on the price for the whole shopping basket than on individual product prices. This induces complementarities between the goods offered at a retail outlet. If the complementarity effect resulting from shopping costs dominates the original substitution effect, the wholesale price negotiated with the first supplier is upward distorted in order to shift rent from the second supplier. As long as the first supplier has only little bargaining power, she compensates the retailer for the upward distorted wholesale price by paying a slotting fee. We also show that banning slotting fees causes per- unit price to fall and welfare to increase
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