Mechanical Engineering / Makina Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4129

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Browsing Mechanical Engineering / Makina Mühendisliği by Department "İzmir Institute of Technology. Photonics"

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    Conference Object
    Bir Ameliyat Robotunun Denetimi için Basitleştirilmiş Dinamik Modeli
    (Otomatik Kontrol Türk Milli Komitesi, 2018-09) Ayit, Orhan; Yaşır, Abdullah; Vardarlı, Eren; Kiper, Gökhan; Dede, Mehmet İsmet Can
    Bu çalışmanın temel konusu minimal invaziv tipi bir ameliyat olan endoskopik hipofiz tümörü ameliyatında kullanılan endoskopun hareket denetimi için geliştirilen robotik sistemdir. Geliştirilen sistemin bu bildiride ele alınan kısmı, ameliyat sırasında sadece ameliyat bölgesi içinde endoskopu cerrahın anlık isteklerine göre yönlendiren, aktif robot yapısıdır. Söz konusu robot uzak hareket merkezli, 3 serbestlik dereceli, paralel kinematik mimariye sahiptir. Bu çalışmada robotun denetimi için uygun görülen hesaplanmış tork yöntemi için gerekli robotun dinamik analizi sunulmaktadır. Denetim algoritmasının yüksek frekansta çalışabilmesi için dinamik denklemlerde yapılan basitleştirmeler ve bunun sonucunda elde edilen hesaplama zamanı sunulmaktadır.
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    Article
    Citation - WoS: 12
    Citation - Scopus: 13
    Parametrizing Nonbonded Interactions Between Silica and Water From First Principles
    (Elsevier, 2020) Özçelik, H. Gökberk; Sözen, Yiğit; Şahin, Hasan; Barışık, Murat
    Silica has been used in a vast number of micro/nano-fluidic technologies where interactions of water with silica at the molecular level play a key role. In such small systems, an understanding of mass and heat transport or surface wetting relies on accurate calculations of the water-silica interface coupling through atomic interactions. Molecular dynamics (MD) is a convenient tool for such use, but force field parameters for nonbonded interactions are required as an input, which are very limited in literature. These interaction parameters can be predicted by density functional theory, but dispersion forces are not calculated in standard models for electron correlations that additional correction models have been proposed at different levels of sophistications, and still under development. Accordingly, this work employs state of the art quantum chemistry to compute the binding energies. Force field parameters for silica/water van der Waals interactions were calculated, and later tested in MD simulations of water droplet on silica surface. While the standard dispersion corrections overestimated the binding energy, Becke-Johnson model yielded interactions parameters recovering experimentally measured wetting behavior of silica with a water contact angle of approximately 12.4 degrees on the flat and clean silica surface. Results will be useful for the current molecular modelling attempts by providing transferable parameters for simple silica/water van der Waals interactions as an alternative to existing complex surface interaction models.