Now showing 1 - 10 of 47499
  • Publication
    Read Rate Optimization of an RFID Tunnel Gate by Using the Concept of an Electromagnetic Reverberation Chamber with Different Q Factors
    ( 2018)
    Schwarz, Sebastian
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    Magdowski, Matthias
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    Vick, Ralf
    ;
    ;
    In this paper, an RFID tunnel gate is optimized in terms of the read rate for bulk reading of several UHF transponders in the frequency range around 865 MHz. Four test series are conducted in order to find the optimum configuration with respect to the transport velocity of transponders and the duration of a pause inside the tunnel, the transmitted power level, additional loading of the tunnel with absorbers and their specific location. The results show that the tunnel behaves like an electromagnetic reverberation chamber with an almost statistically homogenous and isotropic field. The quality factor is one important parameter, whose influence on the read rate is investigated.
  • Publication
    Charakterisierung von Betriebsmitteln für reine Anwendungen
    - Problemstellung und Motivation - Ziel: Beurteilung der Reinraumtauglichkeit von Betriebsmitteln - Grundlagen - kritische Kontaminationen (Überblick) - Reinheits- und Reinraumtauglichkeit - Einflussfaktoren auf die Reinraumtauglichkeit - Grundvoraussetzung Versuchsinfrastruktur - Produktionskette - Einzelne Komponenten des Betriebsmittels - Vorgehensweise der Reinraumtauglichkeits-Klassifizierung (VDI 2083, Blatt 9.1) - Beispiele: Untersuchungen an repräsentativen Betriebsmitteln - Zusammenfassung
  • Publication
    Innovative manufacturing of 3D-lightweight components
    ( 2011) ;
    Dubratz, Markus
    ;
    Stimpfl, Joffrey
    ;
    Emonts, Michael
    Fibre-reinforced plastics (or: fibre-reinforced polymers, FRPs) - a group of materials with excellent and largely adjustable properties - have found their way into many industries over the past years and have established themselves in various sectors. Continuous FRPs have a wide potential for lightweight designs due to their ability to withstand high mechanical loads despite their tare weight. Today's air and space technologies or the wind power industry are unimaginable without this material. Fibre-reinforced components will form one of the most importantkey factors for the European industry with its energy-efficient production to fulfil the increasing global demands e.g. energy efficiency, waste avoidance and reduction of CO2-emissions.
  • Publication
    Wireless multi-gigabit data transmission using active MMIC components at 220 GHz
    ( 2012)
    Antes, J.
    ;
    Lopez-Diaz, D.
    ;
    ; ;
    Massler, Hermann
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    Zwick, T.
    ;
    Ambacher, O.
    ;
    Kallfass, Ingmar
    In this paper we present a wireless data link for multi-gigabit transmission in the mmW frequency range. The link is realized using waveguide modules based on fully integrated 50 nm metamorphic high electron mobility transistor (mHEMT) transmit and receive millimeter wave monolithic integrated circuits (MMICs) and provides transmission of data rates up to 12.5 Gbit/s modulated on a 220 GHz carrier. The receiver input sensitivity is characterized down to values of -38.6 dBm and shows an error rate of 3.0 × 10 -9. Measurements using a coherent link setup show bit error rates better than 1.6 × 10 -9 for a data rate of 10 Gbit/s and a transmission distance of 2 m. For a distance of 20 m a real-time Digital Video Broadcasting - Satellite (DVB-S) television transmission is realized. The signal quality after the wireless link is sufficient for a commercial DVB-S receiver to display the television programs.
  • Publication
    Consideration of inhomogeneous shrinkages for LTCC-applications in panel-level processes
    The aim of our study is a knowledge-based consideration of the inhomogeneous lateral shrinkage (shrinkage field) of commercial Low temperature co-fired ceramic (LTCC-) materials under free sintering conditions to improve the geometrical design fidelity and productions yield of system packages and microsystems fabricated in LTCC. Thus the phenomenological investigations of LTCC materials under various lamination and sintering conditions are presented. Deduced from this, feasible approaches for the compensation of the inhomogeneous shrinkages are introduced. Further thermal as well as thermomechanical analysis distinguish the origin of the shrinkage fields and enable the knowledge-based control of the shrinkage behavior in the design and fabrication process as well as in the material development.
  • Publication
    Increase of capacity flexibility in manufacturing systems by substitution of product functions
    ( 2016)
    Holtewert, Philipp
    ;
    In the current competitive market manufacturing companies are driven by significant price pressure as well as high fluctuation in demand. They are faced with the challenge of producing products cost-effectively. Especially, serial and variant manufacturers strive for high capacity utilization to prevent overcapacity and to reduce their fixed costs in production. By applying current approaches companies are able to react on market turbulences by adapting the manufacturing system in the limits of a defined flexibility corridor. However, with these the existence of overcapacity is not eliminated. In particular, an alternative approach for short and medium term adjustments in the existing manufacturing system has to be given. Consequently, the objective is the efficient use of overcapacity. For this purpose, in this article a new approach to increase the capacity flexibility in manufacturing systems is described. The core approach ""Substitution of Product Functions" focuses on manufacturing two different variants of product components with the same product function simultaneously but two different product designs. One of the component designs needs a high process time with low variable costs, the other one a low process time with high variable costs. Thus, two product designs with differentiation in variable costs allow the use of the factor ""manufacturing process time"" as an additional control variable for increasing the capacity flexibility. The main result will be a cost-optimized and highly utilized manufacturing process. Based on previous scientific studies in this article the results of the influence on costs and capacity flexibility by variation of the product design and design of manufacturing system are presented.
  • Publication
    Process monitoring of abrasive waterjet formation
    Difficult to machine materials require innovative processing solutions for a stable and high quality contouring process of complex forms. Abrasive waterjet cutting gains in importance due to the continuous development of novel high performance materials and multi-material components. A reliable process monitoring during the machining operation becomes essential to avoid waste production. However, the measurement of the process conditions during abrasive waterjet cutting is difficult based on the rough environment inside the machining zone. In this paper appropriate methods for in-process monitoring of the jet conditions, in particular the critical nozzle wear as well as other process output parameters are being tested, discussed and classified.
  • Publication
    N-heterocyclic carbene containing element organic frameworks as heterogeneous organocatalysts
    ( 2011)
    Rose, Marcus
    ;
    Notzon, Andreas
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    Heitbaum, Maja
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    Nickerl, Georg
    ;
    Paasch, Silvia
    ;
    Brunner, Eike
    ;
    Glorius, Frank
    ;
    A bifunctional imidazolium linker was used for the production of highly crosslinked element organic frameworks by Suzuki-coupling with tetrafunctional boronic acids. The resulting porous materials are good heterogeneous organocatalysts in the N-heterocyclic carbene-catalyzed conjugated umpolung of a,v-unsaturated cinnamaldehyde.