247 research outputs found

    Modeling and simulation of film blowing process

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    Film blowing process is a flexible mass production technology used for manufacturing thin polymeric films. Its flexibility in using an existing die to produce films of different width and thickness, just by controlling process conditions such as, extrudate velocity, excess pressure, and line speed, makes it an attractive process with less capital investment. Controlling the process conditions to obtain a stable bubble, however, is not a trivial task. It is a costly trial and error procedure, which could result is a large wastage of material and other resources. Hence, it is necessary to develop methods to simulate the process and design it using numerical experiments. This important need of the industry defines the objective of this work. In this dissertation, a transient, axisymmetric, nonisothermal, viscoelastic model is developed to simulate the process, and it is solved using finite element method. Material behavior of polymer melt is described using a modified Phan-Thien-Tanner model in the liquid??like region, and anisotropic Kelvin??Voight model in the solid zone, and the transition is modeled using a simple mixture theory. Crystallization kinetics is described using a modified Avrami model with factors to account for the influence of temperature and strain. Results obtained are compared with available experimental results and the model is used to explore stability issues and the role of different parameters. Software developed using this model comes with a GUI based pre- and post-processor, and it can be easily adapted to use other constitutive models

    Modeling and simulation of film blowing process

    Get PDF
    Film blowing process is a flexible mass production technology used for manufacturing thin polymeric films. Its flexibility in using an existing die to produce films of different width and thickness, just by controlling process conditions such as, extrudate velocity, excess pressure, and line speed, makes it an attractive process with less capital investment. Controlling the process conditions to obtain a stable bubble, however, is not a trivial task. It is a costly trial and error procedure, which could result is a large wastage of material and other resources. Hence, it is necessary to develop methods to simulate the process and design it using numerical experiments. This important need of the industry defines the objective of this work. In this dissertation, a transient, axisymmetric, nonisothermal, viscoelastic model is developed to simulate the process, and it is solved using finite element method. Material behavior of polymer melt is described using a modified Phan-Thien-Tanner model in the liquid??like region, and anisotropic Kelvin??Voight model in the solid zone, and the transition is modeled using a simple mixture theory. Crystallization kinetics is described using a modified Avrami model with factors to account for the influence of temperature and strain. Results obtained are compared with available experimental results and the model is used to explore stability issues and the role of different parameters. Software developed using this model comes with a GUI based pre- and post-processor, and it can be easily adapted to use other constitutive models

    Wireless strain sensing system for assessing condition of civil infrastructure facilities

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    Bežični senzori i senzorske mreže postaju zamjena za tradicionalne sustave za praćenje ponašanja konstrukcija. Njihova je prednost u nižoj cijeni ugradnje jer nema potrebe za polaganjem dugih kabela između senzora i sustava za prikupljanje podataka. U radu se opisuju istraživanja provedena u svrhu ocjenjivanja učinkovitosti bežičnih senzora za mjerenje relativnih deformacija. Dan je primjer primjene bežičnog senzorskog sustava pri mjerenju ponašanja konstrukcije željezničkog mosta te je napravljena usporedba s primjenom klasičnih sustava.Wireless sensors and sensor networks are emerging as substitutes for traditional structural monitoring systems. Their benefit lies in a lower cost of installation because extensive wiring is no longer required between sensors and the data acquisition system. Studies carried out to evaluate performance of wireless strain measurement units are described in this paper. An example is given of a wireless system used for measuring behaviour of a railway bridge, and comparison with traditional systems is made

    Spectrum and quench-induced dynamics of spin-orbit coupled quantum droplets

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    We investigate the ground state and dynamics of one-dimensional spin-orbit coupled (SOC) quantum droplets within the extended Gross-Pitaevskii approach. As the SOC wavenumber increases, stripe droplet patterns emerge, with a flat-top background, for larger particle numbers. The surface energy decays following a power-law with respect to the interactions. At small SOC wavenumbers, a transition from Gaussian to flat-top droplets occurs for either a larger number of atoms or reduced intercomponent attraction. The excitation spectrum shows that droplets for relatively small SOC wavenumbers are stable, otherwise stripe droplets feature instabilities as a function of the particle number or the interactions. We also witness rich droplet dynamical features using velocity imprinting and abrupt changes in the intercomponent interaction or the SOC parameters. Characteristic responses include breathing oscillations, expansion, symmetric and asymmetric droplet fragmentation, admixtures of single and stripe droplet branches, and erratic spatial distributions suggesting the triggering of relevant instabilities. Our results reveal the controlled dynamical generation and stability properties of stripe droplets that should be detectable in current cold-atom experiments.Comment: 18pages, 13figure

    COMPARATIVE DOCKING STUDIES ON THE EFFECT OF COMMERCIAL DRUGS ON DIPEPTIDYL PEPTIDASE-4 (DPP-4)

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    Objective: The aim of our study was to validate the accuracy of computational tools in drug discovery and molecular interaction studies by studying the inhibitory activity of various commercial drugs on DPP-4.Methods: In order to validate the accuracy of computational tools, 50 commercially available drugs were docked with DPP-4, a major target for type 2 diabetes treatment. Studies were performed using Discovery studio 3.5.Results: The analysis showed that out of the fifty selected drugs, 33 drugs passed the Lipinski's rule and commercially prescribed drugs namely Sulfonylurea, Pregabalin and Metaformin were found to have maximum interaction with the target.Conclusion: These major drugs which yielded the best results were found to be used in the treatment of diabetes which reconfirms the efficacy of these drugs, druggability of the target as well as the accuracy of the tool used

    Development of CMAS Resistant Thermal Barrier Coatings: Challenges and Implications

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    Intelligent Financial Fraud Detection Practices: An Investigation

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    Financial fraud is an issue with far reaching consequences in the finance industry, government, corporate sectors, and for ordinary consumers. Increasing dependence on new technologies such as cloud and mobile computing in recent years has compounded the problem. Traditional methods of detection involve extensive use of auditing, where a trained individual manually observes reports or transactions in an attempt to discover fraudulent behaviour. This method is not only time consuming, expensive and inaccurate, but in the age of big data it is also impractical. Not surprisingly, financial institutions have turned to automated processes using statistical and computational methods. This paper presents a comprehensive investigation on financial fraud detection practices using such data mining methods, with a particular focus on computational intelligence-based techniques. Classification of the practices based on key aspects such as detection algorithm used, fraud type investigated, and success rate have been covered. Issues and challenges associated with the current practices and potential future direction of research have also been identified.Comment: Proceedings of the 10th International Conference on Security and Privacy in Communication Networks (SecureComm 2014

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