School Of Basic And Applied Sciences

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Subject: search.filters.subject.Deposition rates

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    Guided run-and-tumble active particles: wall accumulation and preferential deposition
    (Royal Society of Chemistry, 2021-09-20T00:00:00) Singh, Chamkor
    Bacterial biofilms cost an enormous amount of resources in the health, medical, and industrial sectors. To understand early biofilm formation, beginning from planktonic states of active suspensions (such asEscherichia coli) to micro-colonization, it is vital to study the mechanics of cell accumulation near surfaces and subsequent deposition. Variability in bacterial motion strategies and the presence of taxis fields make the problem even more multifaceted. In this study, analytical expressions for the density and angular distributions, mean orientation, and deposition rates in such bacterial suspensions are derived, with and without the effects of external guiding or taxis fields. The derived results are closely verified by simulations of confined active particles using run-and-tumble statistics from multiple past experiments and utilizing a preferential sticking probability model for deposition. The behavioral changes in cell running strategies are modeled by varying the run-time distribution from an exponential to a heavy-tailed one. It is found that the deposition rates can be altered significantly by a guiding torque but are less affected by a change in the cell running behavior. However, both the mechanisms alter the pair correlation function of the deposited structures. The factor behind the changes in the architecture of deposited biomass under a torque generating guiding field turns out to be an asymmetrical rotational drift of planktonic cells, which can be an important physical mechanism behind the organization in confined active particle suspensions. � The Royal Society of Chemistry 2021.
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    Paschen curve approach to investigate electron density and deposition rate of Cu in magnetron sputtering system
    (Taylor and Francis Inc., 2016) Gopikishan, S.; Banerjee, I.; Bogle, K.A.; Das, A.K.; Pathak, A.P.; Mahapatra, S.K.
    In this work, Paschen curve for argon gas was obtained during copper deposition using a DC magnetron sputtering system. Five process parameters of Paschen curve were used to obtain the electron density and deposition rate of the deposited nanostructured thin films. Plasma parameter such as electron density was correlated with the deposition rate. It is observed that a minimum deposition rate was obtained for the plasma process parameter corresponding to the Paschen minimum. This investigation helps to understand and optimize the quality of nanostructured thin films depending on the process parameters. ? 2016 Informa UK Limited, trading as Taylor & Francis Group.
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    Axial distribution of plasma fluctuations, plasma parameters, deposition rate and grain size during copper deposition
    (Taylor and Francis Inc., 2017) Gopikishan, S.; Banerjee, I.; Pathak, Anand; Mahapatra, S. K.
    Floating potential fluctuations, plasma parameters and deposition rate have been investigated as a function of axial distance during deposition of copper in direct current (DC) magnetron sputtering system. Fluctuations were analyzed using phase space, power spectra and amplitude bifurcation plots. It has been observed that the fluctuations are modified from chaotic to ordered state with increase in the axial distance from cathode. Plasma parameters such as electron density (ne), electron temperature (Te) and deposition rate (Dr) were measured and correlated with plasma fluctuations. It was found that more the deposition rate, greater the grain size, higher the electron density, higher the electron temperature and more chaotic the oscillations near the cathode. This observation could be helpful to the thin film technology industry to optimize the required film. ? 2017 Informa UK Limited, trading as Taylor & Francis Group.