Researcher:
Baloch, Shadi Khan

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PhD Student

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Shadi Khan

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Baloch

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Baloch, Shadi Khan

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2017 - 20183

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Researcher Of Publications: search.filters.isAuthorOfPublication.5186b646-0e5d-42d5-929c-bdbea8c3b750

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    Characterization of fluid mixtures at high pressures using frequency response of microcantilevers
    (2017) Bozkurt, Asuman Aşıkoğlu; Jonas, Alexandr; Department of Chemical and Biological Engineering; N/A; Department of Physics; Department of Mechanical Engineering; Department of Chemical and Biological Engineering; Eris, Gamze; Baloch, Shadi Khan; Kiraz, Alper; Alaca, Burhanettin Erdem; Erkey, Can; Researcher; PhD Student; Faculty Memeber; Faculty Member; Faculty Member; Department of Physics; Department of Mechanical Engineering; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); College of Engineering; Graduate School of Sciences and Engineering; College of Sciences; College of Engineering; College of Engineering; N/A; N/A; 22542; 115108; 29633
    The frequency response of ferromagnetic nickel microcantilevers immersed in binary mixtures of carbon dioxide (CO2) and nitrogen (N-2) at 308 K and pressures up to 23 MPa was investigated. Experimental data were analyzed using the model developed by Sader for a clamped oscillatory beam immersed in a fluid and a very good agreement between the measured resonant frequencies and quality factors (Q factors) and the theoretical predictions of the model with cantilever characteristic parameters regressed from experimental data was observed. This suggested that the data could be used to simultaneously measure the density and the viscosity of fluid mixtures over a wide range of pressures. Subsequently, density and viscosity of binary mixtures of CO2 and N-2 were determined using N-2 as the reference fluid and compared to the predictions of Gerg equation of state and Chung equation, respectively. For the studied fluids with different compositions, the average relative difference between the experimental density values and the values predicted using Gerg equation of state and NIST database ranged from 1.0 to 13%. The average relative difference between the experimental viscosity values and the values obtained using Chung equation and NIST database ranged from 2.4 to 15%. Since the resonant frequency and Q factor were found to vary with composition at a fixed temperature and pressure, the technique can in principle also be used to measure the composition of a binary mixture at a fixed temperature and pressure. The study represents the first systematic attempt to use microcantilevers for the characterization of high-pressure fluid mixtures and paves the way for devising portable sensors for in-line monitoring of thermophysical properties and composition of fluid mixtures under a wide range of environmental conditions. (C) 2017 Elsevier B.V. All rights reserved.
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    Sensitivity of compositional measurement of high-pressure fluid mixtures using microcantilever frequency response
    (Elsevier Science Sa, 2018) Jonas, Alexandr; Department of Physics; Department of Mechanical Engineering; Department of Chemical and Biological Engineering; N/A; Kiraz, Alper; Alaca, Burhanettin Erdem; Erkey, Can; Baloch, Shadi Khan; Faculty Member; Faculty Member; Faculty Member; PhD Student; Department of Physics; Department of Mechanical Engineering; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); College of Sciences; College of Engineering; College of Engineering; Graduate School of Sciences and Engineering; 22542; 115108; 29633; N/A
    Frequency response of an oscillating microcantilever immersed in a fluid mixture can be used to determine the composition of the mixture over a wide range of temperatures and pressures. The Limit of Detection (LOD) in such measurements carried out at high pressures is of great interest for monitoring technologically important processes such as supercritical drying of aerogels. We studied compositional measurement sensitivity of cantilevers defined as the derivative of the cantilever resonant frequency or quality factor with respect to the fluid mixture composition. On the basis of Sader's model of hydrodynamic interaction of an oscillating immersed cantilever with the surrounding fluid, we derived analytical expressions for the sensitivity that were found to be complex functions of the density and viscosity of the mixture as well as the length, width, thickness, and density of the cantilever. We measured the frequency response of cantilevers immersed in ethanol-CO2 mixtures containing 0 - 0.04 wt fraction of ethanol at 318 K and within the pressure range 10-21 MPa. Using the measured resonant frequency and quality factor together with previously published density and viscosity data for ethanol-CO2 mixtures of various compositions, we calculated the sensitivity at each pressure and temperature and determined the LOD of the measurement. In particular, with our current setup, the LOD ranged from 0.0009 to 0.0071 wt fraction of ethanol in the mixture in the pressure range 10-21 MPa for a 150 mu m long cantilever. Our results convincingly illustrate the potential of miniature cantilever-based probes for fast and sensitive in-situ detection of the composition of fluid mixtures in practical technological processes carried out at high pressures.
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    Determination of composition of ethanol-CO2 mixtures at high pressures using frequency response of microcantilevers
    (Elsevier Science Bv, 2018) Jonas, Alexandr; Department of Physics; Department of Mechanical Engineering; Department of Chemical and Biological Engineering; N/A; Kiraz, Alper; Alaca, Burhanettin Erdem; Erkey, Can; Baloch, Shadi Khan; Faculty Member; Faculty Member; Faculty Member; PhD Student; Department of Physics; Department of Mechanical Engineering; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); College of Sciences; College of Engineering; College of Engineering; Graduate School of Sciences and Engineering; 22542; 115108; 29633; N/A
    The measurement of the composition of ethanol-CO2 mixtures at high pressures is important in many applications involving supercritical fluids such as drying of alcogels or release of MEMs. Resonant frequency and quality factor (Q-factor) of microcantilevers immersed in ethanol-CO2 mixtures were measured at a temperature of 308 K and pressure range from 8 MPa to 22 MPa. The measurements were carried out for different mixture compositions ranging from 0.91 to 6.16 wt% of ethanol in CO2. At a given pressure and temperature, the resonant frequencies were found to decrease linearly with the increasing ethanol weight percent in the mixture. The sensitivity of the resonant frequency to changes in composition was found to increase with decreasing pressure. The experimental results show that ethanol-CO2 mixture composition can be determined with good accuracy using mainly the measured resonant frequency of microcantilevers.