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158 results on '"Ooi, Chin Hong"'

18. Controllable high-performance liquid marble micromixer

Author

Nguyen, Nhat-Khuong, primary, Singha, Pradip, additional, Dai, Yuchen, additional, Rajan Sreejith, Kamalalayam, additional, Tran, Du Tuan, additional, Phan, Hoang-Phuong, additional, Nguyen, Nam-Trung, additional, and Ooi, Chin Hong, additional

Published
2022
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26. Dynamic Behaviours of Monodisperse Double Emulsion Formation in a Tri-Axial Capillary Device.

Author

Dai, Yuchen, Cha, Haotian, Nguyen, Nhat-Khuong, Ouyang, Lingxi, Galogahi, Fariba, Yadav, Ajeet Singh, An, Hongjie, Zhang, Jun, Ooi, Chin Hong, and Nguyen, Nam-Trung

Subjects
EMULSIONS, CAPILLARIES, COMPUTATIONAL fluid dynamics
Abstract

We investigated experimentally, analytically, and numerically the formation process of double emulsion formations under a dripping regime in a tri-axial co-flow capillary device. The results show that mismatches of core and shell droplets under a given flow condition can be captured both experimentally and numerically. We propose a semi-analytical model using the match ratio between the pinch-off length of the shell droplet and the product of the core growth rate and its pinch-off time. The mismatch issue can be avoided if the match ratio is lower than unity. We considered a model with the wall effect to predict the size of the matched double emulsion. The model shows slight deviations with experimental data if the Reynolds number of the continuous phase is lower than 0.06 but asymptotically approaches good agreement if the Reynolds number increases from 0.06 to 0.14. The numerical simulation generally agrees with the experiments under various flow conditions. [ABSTRACT FROM AUTHOR]

Published
2022
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27. Wide-Band-Gap Semiconductors for Biointegrated Electronics: Recent Advances and Future Directions

Author

Nguyen, Nhat-Khuong, primary, Nguyen, Thanh, additional, Nguyen, Tuan-Khoa, additional, Yadav, Sharda, additional, Dinh, Toan, additional, Masud, Mostafa Kamal, additional, Singha, Pradip, additional, Do, Thanh Nho, additional, Barton, Matthew J., additional, Ta, Hang Thu, additional, Kashaninejad, Navid, additional, Ooi, Chin Hong, additional, Nguyen, Nam-Trung, additional, and Phan, Hoang-Phuong, additional

Published
2021
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39. Liquid Marble Based Digital Microfluidics

Author

Nguyen, Nam-Trung, Dao, Dzung V, Ooi, Chin Hong, An, Hongjie, Kamalalayam Rajan, Sreejith, Nguyen, Nam-Trung, Dao, Dzung V, Ooi, Chin Hong, An, Hongjie, and Kamalalayam Rajan, Sreejith

Abstract

Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Eng & Built Env, Science, Environment, Engineering and Technology, Sample handling with liquid marbles is a recent advancement in digital microfluidics. Liquid marbles are liquid droplets coated with fine hydrophobic/oleophobic particles. The external particle coating isolates the liquid droplet from the surrounding ensuring a contamination-free environment for the droplet. Mobility manipulation of the liquid marble is easier and well developed compared to the droplet counterpart. These advantages have promoted the usage of liquid marbles as a microreactor for a range of biological applications. Liquid marbles may help in reducing the non-reusable contaminated plastic waste generated in conventional biochemical reaction chambers such as plastic vials and microfluidic chips. However, the use of liquid marble as a microreactor is limited to room-temperature applications as they are susceptible to the problems of evaporation at elevated temperatures. The development of a liquid marble based digital platform for biochemical applications at elevated temperature would broaden the scope of liquid marbles, reducing the generation of contaminated plastic waste. Polymerase Chain Reaction (PCR), a DNA amplification technique is a high-temperature process, which finds application in medical diagnosis, agriculture and forensics. Millions of PCRs are carried out in plastic vials and conventional microfluidic chips annually, contributing to the increasing problem of plastic waste. So developing a liquid marble based digital microfluidic platform tailored for PCR has an immense significance. This Ph.D. thesis focusses on the development of a liquid marble-based digital microfluidic platform particularly for carrying out PCR. A basic PCR process consists of three different phases namely sample dispersion, thermal cycling, and output monitoring. Sample dispersion process should be precise and contamination-free. Manual intervention in sample dispersion should be minimised to avoid the contamination of the sample and to achieve the precise volume. We

Published
2020

40. Direct measurement of the contents, thickness, and internal pressure of molybdenum disulfide nanoblisters

Author

Tan, Beng Hau, Zhang, Jun, Jin, Jing, Ooi, Chin Hong, He, Yi, Zhou, Renwu, Ostrikov, Kostya, Nguyen, Nam Trung, An, Hongjie, Tan, Beng Hau, Zhang, Jun, Jin, Jing, Ooi, Chin Hong, He, Yi, Zhou, Renwu, Ostrikov, Kostya, Nguyen, Nam Trung, and An, Hongjie

Abstract

Nanoblisters have attracted attention due to their ability to controllably modulate the properties of two-dimensional materials. The accurate measurement or estimation of their properties is nontrivial and largely based on Hencky's theory. However, these estimates require a priori knowledge of material properties and propagate large errors. Here we show, through a systematic atomic force microscopy study, several strategies that lead to vastly enhanced characterization of nanoblisters. First, we find that nanoblisters may contain both liquid and gas, resolving an ongoing debate in the literature. Second, we demonstrate how to definitively determine the membrane thickness of a nanoblister and show that Hencky's theory can only reliably predict membrane thicknesses for small aspect ratios and small membrane thicknesses. Third, we develop a novel technique to measure the internal pressures of nanoblisters, which quantitatively agrees with Hencky's theory but carries a 1 order smaller propagated error.

Published
2020

41. Investigation of liquid marble shell using X‐ray: shell thickness and effective surface tension.

Author

Singha, Pradip, Nguyen, Nhat‐Khuong, Nguyen, Van Thuong, Sreejith, Kamalalayam Rajan, Tran, Du Tuan, Nguyen, Anh V., Nguyen, Nam‐Trung, and Ooi, Chin Hong

Subjects
MARBLE, X-ray computed microtomography, LIQUIDS, LIQUID surfaces, GRAVITATION
Abstract

Liquid marble is a non‐wetting droplet encapsulated by micro‐ or nano‐sized hydrophobic particles. Recently, liquid marble has been emerging as a tool for digital microfluidics. Thus, a detailed understanding of the fundamentals of liquid marble is essential. The shell of a liquid marble has an opaque and fuzzy appearance which hinders in‐depth investigation using conventional optical microscopy. We used X‐ray computerized microtomography (CMT) to generate an image with a visible interface between the core liquid and the shell to overcome this problem. The interface facilitates accurate measurement of the shell thickness and the effective surface tension. This work investigates the effect of liquid marble preparation methods and liquid marble volumes on shell thickness and effective surface tension. We found that increasing the revolution speed during liquid marble preparation increases shell thickness. A liquid marble shell has a uniform packing when the revolution speed is 200–300 rpm. We also found that the effective surface tension of liquid marbles decreases with increasing volume. This could be due to a stronger effect of gravitational force for a large liquid marble. The findings from this work could provide a new insight into the characterization of liquid marble and open up a new direction of fundamental research of liquid marble shell. [ABSTRACT FROM AUTHOR]

Published
2022
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46. Effect of Core Liquid Surface Tension on the Liquid Marble Shell.

Author

Singha, Pradip, Nguyen, Nhat‐Khuong, Sreejith, Kamalalayam Rajan, An, Hongjie, Nguyen, Nam‐Trung, and Ooi, Chin Hong

Subjects
LIQUID surfaces, SURFACE tension measurement, MARBLE, SURFACE tension, CELL culture
Abstract

Liquid marble is a non‐wetting droplet coated with micro‐ or nanometer sized particles and exhibits great versatility as a standalone system. Unique features such as low evaporation rate, low friction, and a porous shell enable it to be a potential tool for gas sensing, cell culture, and drug delivery. With the growing number of interests in these fields, it is important to understand the structure of the liquid marble shell and how it behaves with the variation of the surface tension of the core liquid. This paper investigates the thickness and the mass of liquid marble shell at various surface tension values. Surfactant mediated surface tension reduction allows the encapsulating particles to penetrate more into the core liquid and decreases the shell thickness. The shell thickness decreases significantly with the surface tension, whereas the mass remains almost constant. Interestingly, the trend reverses with further decrease of the surface tension. In this regime, both the thickness and the mass of the shell increase due to interfacial jamming. This work provides a new insight into understanding the contribution of the particle distribution at the shell for the stability and the measurement of the effective surface tension of a liquid marble. [ABSTRACT FROM AUTHOR]

Published
2021
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