Article
Chemistry, Analytical
Chang Chen, Panpan Li, Tianruo Guo, Siyuan Chen, Dong Xu, Huaying Chen
Summary: This study developed a microfluidic device that allows dynamic variations of concentration in a channel and concentration distribution in multiple channels by adjusting the flow resistance using programmable pneumatic microvalves. The device offers superior application potentials in analytical chemistry, drug screening, and cell biology research.
Article
Mechanics
Gloire Imani, Lei Zhang, Chao Xu, Munezero Ntibahanana, Hai Sun, Jun Yao
Summary: In this study, direct numerical simulations were conducted to compare the release conditions of finite droplets and long droplets in three-dimensional constrained channels. The results showed that for finite droplets, the maximum pressure increases with the increase in the contact angle, while for long droplets, the maximum pressure is almost the same in water-wet and neutral-wet conditions. The study also found that droplet size affects the release pressure, with the minimum release pressure of finite droplets increasing linearly with the droplet length in water-wet conditions, and the minimum release pressure of long droplets not changing much as the length increases. Furthermore, the release pressure decreases with the increased tapering angle.
Article
Mechanics
C. Ruyer-Quil, D. Bresch, M. Gisclon, G. L. Richard, M. Kessar, N. Cellier
Summary: A mathematical and numerical framework is proposed to compute the displacement and merging dynamics of sliding droplets under the action of a constant shear exerted by a gas flow. The model includes surface tension with the full curvature of the free surface, shallow-water evolution equations, and an additional quantity taking into account capillary effects and enstrophy. The model is hyperbolic and considers the effect of viscosity and shear stress. The model is completed with a disjoining pressure formulation that accounts for the hysteresis of the static contact angle.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Engineering, Chemical
O. Orozovic, A. Lavrinec, R. McCloy, M. H. Meylan
Summary: This paper addresses the challenge of relating the dynamic properties of individual slugs to steady feed rates by developing a numerical framework for modeling single slugs. The framework, based on finite difference approximation, provides a fundamental and quantitative tool for analyzing slug dynamics and serves as a foundation for further research.
Article
Robotics
Sagar Joshi, Jamie Paik
Summary: Soft actuators using pressurized air are widely used in soft robotics, and optimizing the pneumatic supply system (PSS) is crucial for meeting the desired soft actuator performance and specifications.
Article
Nanoscience & Nanotechnology
Sagar N. Agnihotri, Mohammad Reza Raveshi, Rajneesh Bhardwaj, Adrian Neild
Summary: This paper demonstrates a selective multisite splitting and merging system using single-layer microfluidic valves, offering simplicity, biocompatibility, and high-speed operation. These valves control the generation of droplets and splitting locations, as well as allow for merging different types of droplets.
MICROFLUIDICS AND NANOFLUIDICS
(2021)
Article
Nanoscience & Nanotechnology
Lang Nan, Tianjiao Mao, Ho Cheung Shum
Summary: This study proposes a microfluidic design for the self-synchronization of reinjected droplets, enabling high-efficiency merging. The design utilizes droplet blocking to induce periodic increase in hydrodynamic resistance, allowing automatic droplet pairing. The system achieves 100% synchronization efficiency, even with a 10% mismatch rate, and can synchronize over 98% of droplets at nonuniform sizes and fluctuating reinjection flow rates. In addition, the system allows for flexible adjustment of droplet pairing ratio for on-demand sample addition.
MICROSYSTEMS & NANOENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
H. J. Holweger, M. Jamali, H. Vahedi Tafreshi
Summary: This study presents the first experimental-computational research on the centrifugal detachment of compound droplets from a fiber, focusing on the interplay between interfacial and external forces. Experimental observations showed differences in behavior between silicone-oil-cloaked droplets and mineral-oil-cloaked droplets, as well as a decrease in detachment force with increasing oil-to-water volume ratio. Simulations using the Surface Evolver code revealed the evolution of interfacial forces and allowed for the definition of effective interfacial tensions and contact angles for detaching compound droplets, showing reasonable agreement with experimental measurements.
Article
Biochemical Research Methods
Saurabh Vyawahare, Michael Brundage, Aleksandra Kijac, Michael Gutierrez, Martina de Geus, Supriyo Sinha, Andrew Homyk
Summary: The study introduces a new droplet sorting system with several new elements, including new electrode design, modular multi-sorting fluidic design, timing parameters based on signal triggers, droplet collection techniques, and emulsion breaking method. These technologies are used to build a high-purity fluorescence-based cell sorter and demonstrate the translation of these microfluidic designs into injection molded thermoplastics suitable for industrial production. The advantages and limitations of these devices are also summarized.
Article
Biochemical Research Methods
Runtao Zhong, Mengyu Wang, Bingcheng Lin
Summary: A microfluidic DNA extraction protocol based on integrated diaphragm microvalves/pumps and silica-deposited open-channel columns was developed for automated and parallel DNA solid-phase extraction. The method uses microfluidic chips with a sandwiched structure containing three layers, enabling the processing of multiple samples in parallel without changing the microvalve control module. The integrated microvalves/pumps allow for automated, programmable, and simultaneous DNA extractions from different samples, even from complex solutions, with stable and reliable reuse of the silica-deposited open-channel columns.
Article
Construction & Building Technology
Lianjun Chen, Hui Ma, Kang Gao, Zhenjiao Sun
Summary: This experimental study investigates the gas-solid two-phase flow of stiff shotcrete in horizontal pneumatic conveying to reveal its flow characteristics. Pressure and particle flow characteristics were measured using a pressure transmitter and high-speed camera. The unit pressure drop and particle flow characteristics were systematically studied under different air volumes, water cement ratios, and pipe diameters. The results show that the unit pressure drop increases with the water-cement ratio, while the pressure drop per unit length in the steady state zone initially decreases and then increases with the air volume. Image analysis reveals a transition from stratified flow to suspended flow as the air volume increases. The stability of stiff shotcrete during pneumatic conveying is also studied, with the stability increasing as the pressure variation coefficient decreases. This study provides essential guidance for designing pneumatic conveying systems and serves as an experimental basis for stiff shotcrete.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Nanoscience & Nanotechnology
Maren Umlandt, Alexey Kopyshev, Sergey Pasechnik, Alexandre Zakharov, Nino Lomadze, Svetlana Santer
Summary: Researchers have developed a method of light-triggered droplet manipulation, which includes reversible wetting, splitting, merging, and transport. By applying soft optical stimuli, they are able to change the wetting properties and surface morphology of microscopic droplets, allowing for precise manipulation and movement of the droplets.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Tristan Gilet, Stephanie van Loo
Summary: In this study, the interaction between microfluidic droplets and pneumatic valves in droplet arrays was investigated experimentally and theoretically. Two main trapping modes were characterized, and the significant increase of hydrodynamic resistance induced by the droplet/valve interaction was quantified. Transitions between trapped and non-trapped regimes were rationalized using a generic theoretical model.
MICROFLUIDICS AND NANOFLUIDICS
(2022)
Review
Mechanics
Vladimir S. Ajaev, Oleg A. Kabov
Summary: The review focuses on studying the physical mechanisms of levitating droplets over liquid-gas interfaces and dry solid surfaces. It also discusses the self-organization of levitating droplets into large arrays, nonisothermal flotation, levitation of evaporating droplets over a pool of nonvolatile liquid, and recent advances in the study of the Leidenfrost effect.
ANNUAL REVIEW OF FLUID MECHANICS, VOL 53
(2021)
Article
Chemistry, Multidisciplinary
Yanpeng Dong, Xingyu Xiang, Zhongdong Wang, Chunying Zhu, Youguang Ma, Taotao Fu
Summary: In this study, the distribution of fluid flow, as well as the uniformity and stability of droplets, in asymmetrical parallelized microchannels were explored using a high-speed camera. The effects of pressure difference fluctuation at the T-junction, hydrodynamic resistance in microchannels, and shear-thinning property of fluids on flow distribution and droplet formation were revealed. The uniformity and stability of droplets in microdevices with different cavity settings were compared, and an optimal configuration was proposed. Prediction models for the flow distribution of shear-thinning fluids in asymmetrical parallelized microchannels were also established.
Article
Engineering, Electrical & Electronic
Dong Hyun Yoon, Asahi Nakahara, Afshan Jamshaid, Hironobu Sato, Tetsushi Sekiguchi, Shuichi Shoji
JOURNAL OF SENSORS
(2013)
Article
Chemistry, Physical
Jeremy Hieulle, Shulin Luo, Dae-Yong Son, Afshan Jamshaid, Collin Stecker, Zonghao Liu, Guangren Na, Dongwen Yang, Robin Ohmann, Luis K. Ono, Lijun Zhang, Yabing Qi
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2020)
Article
Chemistry, Physical
Zhifang Wu, Maowei Jiang, Zonghao Liu, Afshan Jamshaid, Luis K. Ono, Yabing Qi
ADVANCED ENERGY MATERIALS
(2020)
Article
Chemistry, Physical
Guoqing Tong, Dae-Yong Son, Luis K. Ono, Yuqiang Liu, Yanqiang Hu, Hui Zhang, Afshan Jamshaid, Longbin Qiu, Zonghao Liu, Yabing Qi
Summary: The study introduces a strategy to fabricate large-area uniform and dense perovskite films with the addition of NH4Cl to the precursor solution. The resulting perovskite solar modules demonstrate high efficiency and good operational stability, exceeding 1600 hours of T-80 lifetime for the 5 x 5 cm^2 module.
ADVANCED ENERGY MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Nikhil Bhalla, Afshan Jamshaid, Mandy H. M. Leung, Noriko Ishizu, Amy Q. Shen
ACS APPLIED NANO MATERIALS
(2019)