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Cai S, Jin Y, Lin Y, He Y, Zhang P, Ge Z, Yang W. Micromixing within microfluidic devices: Fundamentals, design, and fabrication. BIOMICROFLUIDICS 2023; 17:061503. [PMID: 38098692 PMCID: PMC10718651 DOI: 10.1063/5.0178396] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/24/2023] [Indexed: 12/17/2023]
Abstract
As one of the hot spots in the field of microfluidic chip research, micromixers have been widely used in chemistry, biology, and medicine due to their small size, fast response time, and low reagent consumption. However, at low Reynolds numbers, the fluid motion relies mainly on the diffusive motion of molecules under laminar flow conditions. The detrimental effect of laminar flow leads to difficulties in achieving rapid and efficient mixing of fluids in microchannels. Therefore, it is necessary to enhance fluid mixing by employing some external means. In this paper, the classification and mixing principles of passive (T-type, Y-type, obstructed, serpentine, three-dimensional) and active (acoustic, electric, pressure, thermal, magnetic field) micromixers are reviewed based on the presence or absence of external forces in the micromixers, and some experiments and applications of each type of micromixer are briefly discussed. Finally, the future development trends of micromixers are summarized.
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Affiliation(s)
- Shuxiang Cai
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai 264005, China
| | - Yawen Jin
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai 264005, China
| | - Yun Lin
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai 264005, China
| | - Yingzheng He
- School of Mechanical Engineering, Naval Aviation University, Yantai 264005, China
| | - Peifan Zhang
- School of Mechanical Engineering, Naval Aviation University, Yantai 264005, China
| | - Zhixing Ge
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China
| | - Wenguang Yang
- School of Electromechanical and Automotive Engineering, Yantai University, Yantai 264005, China
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Nai J, Zhang F, Dong P, Bai F, Fu T, Wang J, Ge A. Effect of Multiple Structural Parameters on the Performance of a Micromixer with Baffles, Obstacles, and Gaps. MICROMACHINES 2023; 14:1750. [PMID: 37763914 PMCID: PMC10534435 DOI: 10.3390/mi14091750] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023]
Abstract
As an essential component of chip laboratories and microfluidic systems, micromixers are widely used in fields such as chemical and biological analysis. In this work, a square cavity micromixer with multiple structural parameters (baffles, obstacles, and gaps) has been proposed to further improve the mixing performance of micromixers. This study examines the comprehensive effects of various structural parameters on mixing performance. The impact of baffle length, obstacle length-to-width ratio, gap width, and obstacle shape on the mixing index and pressure drop were numerically studied at different Reynolds numbers (Re). The results show that the mixing index increases with baffle length and obstacle length-to-width ratio and decreases with gap width at Re = 0.1, 1, 10, 20, 40, and 60. The mixing index can reach more than 0.98 in the range of Re ≥ 20 when the baffle length is 150 μm, the obstacle length-to-width ratio is 600/100, and the gap width is 200 μm. The pressure drop of the microchannel is proportional to baffle length and obstacle length-to-width ratio. Combining baffles and obstacles can further improve the mixing performance of square cavity micromixers. A longer baffle length, larger obstacle length-to-width ratio, narrower gap width, and a more symmetrical structure are conducive to improving the mixing index. However, the impact of pressure drop must also be considered comprehensively. The research results provide references and new ideas for passive micromixer structural design.
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Affiliation(s)
- Jiacheng Nai
- Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Feng Zhang
- Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Peng Dong
- Key Laboratory of Metallurgical Equipment and Control Technology, Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Fan Bai
- School of Science, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Ting Fu
- Precision Manufacturing Institute, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Jiangbo Wang
- Precision Manufacturing Institute, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Anle Ge
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
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Nai J, Zhang F, Dong P, Fu T, Ge A, Xu S, Pan Y. Influence of Structural Parameters on the Performance of an Asymmetric Rhombus Micromixer with Baffles. MICROMACHINES 2023; 14:545. [PMID: 36984952 PMCID: PMC10059678 DOI: 10.3390/mi14030545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/21/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
As an important part of lab-on-a-chip and micro-total analysis systems, micromixers have a wide range of applications in biochemical analysis, pharmaceutical preparation and material synthesis. In the work, a novel rhombic separation and recombination micromixer with baffles was presented to further improve the performance of the micromixer and study the effect of multiple structural parameters on mixing. The effects of the rhombic angle, the width ratio of sub-channel and the size and relative positions of baffles on the mixing index were studied numerically at different Reynolds numbers (Re), and the sensitivity of the mixing index to various structures was also investigated. The results showed that the mixing index increased with the subchannel's width ratio and slowly decreased after reaching the peak value in the range of Re from 0.1 to 60. The maximum mixing index appeared when the width ratio was 6.5. The pressure drops in the microchannel were proportional to the width ratio. The mixing effect can be further improved by adding baffle structure to asymmetric rhombus micromixer, and more baffle quantity and larger baffle height were beneficial to the improvement of the mixing index. The research results can provide reference and new ideas for the structure design of passive micromixers.
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Affiliation(s)
- Jiacheng Nai
- Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Feng Zhang
- Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Peng Dong
- Key Laboratory of Metallurgical Equipment and Control Technology, Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Ting Fu
- Precision Manufacturing Institute, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Anle Ge
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
| | - Shuang Xu
- Precision Manufacturing Institute, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Yanqiao Pan
- Precision Manufacturing Institute, Wuhan University of Science and Technology, Wuhan 430081, China
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Abdal S, Siddique I, Eldin SM, Bilal M, Hussain S. Significance of thermal radiation and bioconvection for Williamson nanofluid transportation owing to cone rotation. Sci Rep 2022; 12:22646. [PMID: 36587042 PMCID: PMC9805467 DOI: 10.1038/s41598-022-27118-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 12/26/2022] [Indexed: 01/02/2023] Open
Abstract
Numerical investigation for enhancement in thermal distribution of unsteady dynamics of Williamson nanofluids and ordinary nanofluids flow across extending surface of a rotating cone is represented in this communication. Bio-convection of gyrotactic micro-organisms and thermal radiative fluxes with magnetic fields are significant physical aspects of the study. The velocity slip conditions are considered along x and y directions. The leading formulation is transmuted into ordinary differential form via similarity functions. Five coupled equations with non-linear terms are resolved numerically through the utilization of Matlab code for the Runge-Kutta procedure. The parameters of buoyancy ratio and bio-convection Rayleigh number decrease the x-direction velocity. The slip parameter being proportional to viscosity reduces the speed of flow and hence rise in temperature. Also, the temperature rises with the rising values of magnetic field strength, radiative heat transportation, Brownian motion and thermophorsis.
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Affiliation(s)
- Sohaib Abdal
- grid.510450.5Department of Mathematics, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, 64200 Pakistan ,grid.412262.10000 0004 1761 5538School of Mathematics, Northwest University, No. 229 North Taibai Avenue, Xi’an, 7100069 China
| | - Imran Siddique
- grid.444940.9Department of Mathematics, University of Management and Technology, Lahore, 54770 Pakistan
| | - Sayed M. Eldin
- grid.440865.b0000 0004 0377 3762Center of Research, Faculty of Engineering, Future University in Egypt, New Cairo, 11835 Egypt
| | - Muhammad Bilal
- grid.510450.5Department of Mathematics, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, 64200 Pakistan
| | - Sajjad Hussain
- grid.59025.3b0000 0001 2224 0361School of Aerospace and Mechanical Engineering, Nanyang Technological University, Singapore, Singapore
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A Tesla Valve as a Micromixer for Fe3O4 Nanoparticles. Processes (Basel) 2022. [DOI: 10.3390/pr10081648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A large number of microfluidic applications are based on effective mixing. In the application of water purification, the contaminated water needs to be effectively mixed with a solution that is loaded with nanoparticles. In this work, the Tesla valve was used as a micromixer device in order to evaluate the effect of this type of geometry on the mixing process of two streams. For this reason, several series of simulations were performed in order to achieve an effective mixing of iron oxide nanoparticles and contaminated water in a duct. In the present work, a stream loaded with Fe3O4 nanoparticles and a stream with contaminated water were numerically studied for various inlet velocity ratios and initial concentrations between the two streams. The Navier–Stokes equations were solved for the water flow and the discrete motion of particles was evaluated by the Lagrangian method. Results indicate that the Tesla valve can be used as a micromixer since mixing efficiency reached up to 63% for Vp/Vc = 20 under various inlet nanoparticles rates for the geometry of the valve that was used in this study.
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Lee J, Lee S, Lee M, Prakash R, Kim H, Cho G, Lee J. Enhancing Mixing Performance in a Rotating Disk Mixing Chamber: A Quantitative Investigation of the Effect of Euler and Coriolis Forces. MICROMACHINES 2022; 13:mi13081218. [PMID: 36014138 PMCID: PMC9416410 DOI: 10.3390/mi13081218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/20/2022] [Accepted: 07/27/2022] [Indexed: 02/04/2023]
Abstract
Lab-on-a-CD (LOCD) is gaining importance as a diagnostic platform due to being low-cost, easy-to-use, and portable. During LOCD usage, mixing and reaction are two processes that play an essential role in biochemical applications such as point-of-care diagnosis. In this paper, we numerically and experimentally investigate the effects of the Coriolis and Euler forces in the mixing chamber during the acceleration and deceleration of a rotating disk. The mixing performance is investigated under various conditions that have not been reported, such as rotational condition, chamber aspect ratio at a constant volume, and obstacle arrangement in the chamber. During disk acceleration and deceleration, the Euler force difference in the radial direction causes rotating flows, while the Coriolis force induces perpendicular vortices. Increasing the maximum rotational velocity improves the maximum rotational displacement, resulting in better mixing performance. A longer rotational period increases the interfacial area between solutions and enhances mixing. Mixing performance also improves when there is a substantial difference between Euler forces at the inner and outer radii. Furthermore, adding obstacles in the angular direction also passively promotes or inhibits mixing by configuration. This quantitative investigation provides valuable information for designing and developing high throughput and multiplexed point-of-care LOCDs.
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Affiliation(s)
- Jihyeong Lee
- School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Korea; (J.L.); (S.L.)
| | - Saebom Lee
- School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Korea; (J.L.); (S.L.)
| | - Minki Lee
- Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 02792, Korea;
| | - Ritesh Prakash
- Institute of Quantum Biophysics, Sungkyunkwan University, Suwon 16419, Korea;
- Research Engineering Center for R2R Printed Flexible, Sungkyunkwan University, Suwon 16419, Korea
| | - Hyejeong Kim
- School of Mechanical Engineering, Korea University, Seoul 02841, Korea;
| | - Gyoujin Cho
- Institute of Quantum Biophysics, Sungkyunkwan University, Suwon 16419, Korea;
- Research Engineering Center for R2R Printed Flexible, Sungkyunkwan University, Suwon 16419, Korea
- Department of Biophysics, Sungkyunkwan University, Suwon 16419, Korea
- Correspondence: (G.C.); (J.L.)
| | - Jinkee Lee
- School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Korea; (J.L.); (S.L.)
- Institute of Quantum Biophysics, Sungkyunkwan University, Suwon 16419, Korea;
- Correspondence: (G.C.); (J.L.)
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Mahdhi N, Alsaiari NS, Amari A, Chakhoum MA. Effect of TiO 2 Nanoparticles on Capillary-Driven Flow in Water Nanofilters Based on Chitosan Cellulose and Polyvinylidene Fluoride Nanocomposites: A Theoretical Study. Polymers (Basel) 2022; 14:polym14142908. [PMID: 35890682 PMCID: PMC9320925 DOI: 10.3390/polym14142908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/08/2022] [Accepted: 07/12/2022] [Indexed: 11/16/2022] Open
Abstract
In this study, a novel concept of nanofiltration process of drinking water based on capillary-driven nanofiltration is demonstrated using a bio-based nanocomposites’ nanofilter as free power: a green and sustainable solution. Based on Lifshitz and Young–Laplace theories, we show that the chitosan (CS), cellulose acetate (CLA), and Polyvinylidene fluoride (PVDF) polymer matrixes demonstrate hydrophobic behavior, which leads to the draining of water from nanopores when negative capillary pressure is applied and consequently prevents the capillary-driven nanofiltration process. By incorporating 10%, 20%, and 30% volume fraction of titanium dioxide (TiO2) nanoparticles (NPs) to the polymers’ matrixes, we demonstrate a wetting conversion from hydrophobic to hydrophilic behavior of these polymer nanocomposites. Subsequently, the threshold volume fraction of the TiO2 NPs for the conversion from draining (hydrophobic) to filling (hydrophilic) by capillary pressure were found to be equal to 5.1%, 10.9%, and 13.9%, respectively, for CS/TiO2, CLA/TiO2, and PVDF/TiO2 nanocomposites. Then, we demonstrated the negligible effect of the gravity force on capillary rise as well as the capillary-driven flow for nanoscale pore size. For nanofilters with the same effective nanopore radius, porosity, pore shape factor, and tortuosity, results from the modified Lucas–Washburn model show that the capillary rise as well as the capillary-driven water volume increase with increased volume fraction of the TiO2 NPs for all nanocomposite nanofilter. Interestingly, the capillary-driven water volume was in range (5.26–6.39) L/h·m2 with 30% volume fraction of TiO2 NPs, which support our idea for capillary-driven nanofiltration as zero energy consumption nano-filtration process. Correspondingly, the biodegradable CS/TiO2 and CLA/TiO2 nanocomposites nanofilter demonstrate capillary-driven water volume higher, ~1.5 and ~1.2 times, respectively, more than the synthetic PVDF/TiO2 nanocomposite.
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Affiliation(s)
- Noureddine Mahdhi
- Laboratory Materials Organizations and Properties, Tunis El Manar University, Tunis 2092, Tunisia
- Correspondence: (N.M.); (A.A.)
| | - Norah Salem Alsaiari
- Department of Chemistry, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh 11671, Saudi Arabia;
| | - Abdelfattah Amari
- Department of Chemical Engineering, College of Engineering, King Khalid University, Abha 61411, Saudi Arabia
- Research Laboratory of Processes, Energetics, Environment and Electrical Systems, National School of Engineers, Gabes University, Gabes 6072, Tunisia
- Correspondence: (N.M.); (A.A.)
| | - Mohamed Ali Chakhoum
- Laboratoire des Sciences de la Matière Condensée (LSMC), Université Oran 1 Ahmed Ben Bella, Oran 31100, Algeria;
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Antognoli M, Tomasi Masoni S, Mariotti A, Mauri R, Salvetti MV, Brunazzi E, Galletti C. Mixing Improvement in a T-Shaped Micro-Junction through Small Rectangular Cavities. MICROMACHINES 2022; 13:mi13020159. [PMID: 35208284 PMCID: PMC8879540 DOI: 10.3390/mi13020159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/14/2022] [Accepted: 01/19/2022] [Indexed: 11/16/2022]
Abstract
The T-shaped micro-junction is among the most used geometry in microfluidic applications, and many design modifications of the channel walls have been proposed to enhance mixing. In this work, we investigate through numerical simulations the introduction of one pair of small rectangular cavities in the lateral walls of the mixing channel just downstream of the confluence region. The aim is to preserve the simple geometry that has contributed to spread the practical use of the T-shaped micro-junction while suggesting a modification that should, in principle, work jointly with the vortical structures present in the mixing channel, further enhancing their efficiency in mixing without significant additional pressure drops. The performance is analyzed in the different flow regimes occurring by increasing the Reynolds number. The cavities are effective in the two highly-mixed flow regimes, viz., the steady engulfment and the periodic asymmetric regimes. This presence does not interfere with the formation of the vortical structures that promote mixing by convection in these two regimes, but it further enhances the mixing of the inlet streams in the near-wall region of the mixing channel without any additional cost, leading to better performance than the classical configuration.
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Liosis C, Papadopoulou A, Karvelas E, Karakasidis TE, Sarris IE. Heavy Metal Adsorption Using Magnetic Nanoparticles for Water Purification: A Critical Review. MATERIALS (BASEL, SWITZERLAND) 2021; 14:7500. [PMID: 34947096 PMCID: PMC8707578 DOI: 10.3390/ma14247500] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/22/2021] [Accepted: 12/01/2021] [Indexed: 12/12/2022]
Abstract
Research on contamination of groundwater and drinking water is of major importance. Due to the rapid and significant progress in the last decade in nanotechnology and its potential applications to water purification, such as adsorption of heavy metal ion from contaminated water, a wide number of articles have been published. An evaluating frame of the main findings of recent research on heavy metal removal using magnetic nanoparticles, with emphasis on water quality and method applicability, is presented. A large number of articles have been studied with a focus on the synthesis and characterization procedures for bare and modified magnetic nanoparticles as well as on their adsorption capacity and the corresponding desorption process of the methods are presented. The present review analysis shows that the experimental procedures demonstrate high adsorption capacity for pollutants from aquatic solutions. Moreover, reuse of the employed nanoparticles up to five times leads to an efficiency up to 90%. We must mention also that in some rare occasions, nanoparticles have been reused up to 22 times.
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Affiliation(s)
- Christos Liosis
- Department of Civil Engineering, University of Thessaly, 38334 Volos, Greece;
| | - Athina Papadopoulou
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece;
| | - Evangelos Karvelas
- Department of Mechanical Engineering, University of West Attica, 12243 Athens, Greece; (E.K.); (I.E.S.)
- Condensed Matter Physics Lab, Department of Physics, University of Thessaly, 35100 Lamia, Greece
| | - Theodoros E. Karakasidis
- Condensed Matter Physics Lab, Department of Physics, University of Thessaly, 35100 Lamia, Greece
| | - Ioannis E. Sarris
- Department of Mechanical Engineering, University of West Attica, 12243 Athens, Greece; (E.K.); (I.E.S.)
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A Computational Study on Magnetic Nanoparticles Hyperthermia of Ellipsoidal Tumors. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11209526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The modelling of magnetic hyperthermia using nanoparticles of ellipsoid tumor shapes has not been studied adequately. To fill this gap, a computational study has been carried out to determine two key treatment parameters: the therapeutic temperature distribution and the extent of thermal damage. Prolate and oblate spheroidal tumors, of various aspect ratios, surrounded by a large healthy tissue region are assumed. Tissue temperatures are determined from the solution of Pennes’ bio-heat transfer equation. The mortality of the tissues is determined by the Arrhenius kinetic model. The computational model is successfully verified against a closed-form solution for a perfectly spherical tumor. The therapeutic temperature and the thermal damage in the tumor center decrease as the aspect ratio increases and it is insensitive to whether tumors of the same aspect ratio are oblate or prolate spheroids. The necrotic tumor area is affected by the tumor prolateness and oblateness. Good comparison is obtained of the present model with three sets of experimental measurements taken from the literature, for animal tumors exhibiting ellipsoid-like geometry. The computational model enables the determination of the therapeutic temperature and tissue thermal damage for magnetic hyperthermia of ellipsoidal tumors. It can be easily reproduced for various treatment scenarios and may be useful for an effective treatment planning of ellipsoidal tumor geometries.
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Nanoadsorbants for the Removal of Heavy Metals from Contaminated Water: Current Scenario and Future Directions. Processes (Basel) 2021. [DOI: 10.3390/pr9081379] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Heavy metal pollution of aquatic media has grown significantly over the past few decades. Therefore, a number of physical, chemical, biological, and electrochemical technologies are being employed to tackle this problem. However, they possess various inescapable shortcomings curbing their utilization at a commercial scale. In this regard, nanotechnology has provided efficient and cost-effective solutions for the extraction of heavy metals from water. This review will provide a detailed overview on the efficiency and applicability of various adsorbents, i.e., carbon nanotubes, graphene, silica, zero-valent iron, and magnetic nanoparticles for scavenging metallic ions. These nanoparticles exhibit potential to be used in extracting a variety of toxic metals. Recently, nanomaterial-assisted bioelectrochemical removal of heavy metals has also emerged. To that end, various nanoparticle-based electrodes are being developed, offering more efficient, cost-effective, ecofriendly, and sustainable options. In addition, the promising perspectives of nanomaterials in environmental applications are also discussed in this paper and potential directions for future works are suggested.
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The Potential for PE Microplastics to Affect the Removal of Carbamazepine Medical Pollutants from Aqueous Environments by Multiwalled Carbon Nanotubes. TOXICS 2021; 9:toxics9060139. [PMID: 34204690 PMCID: PMC8231597 DOI: 10.3390/toxics9060139] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 11/17/2022]
Abstract
Microplastics are ubiquitous in aquatic environments and interact with other kinds of pollutants, which affects the migration, transformation, and fate of those other pollutants. In this study, we employ carbamazepine (CBZ) as the contaminant to study the influence of polyethylene (PE) microplastics on the adsorption of CBZ pollutants by multiwalled carbon nanotubes (MCNTs) in aqueous solution. The adsorption capacity of CBZ by MCNTs in the presence of PE microplastics was obviously lower than that by MCNTs alone. The influencing factors, including the dose of microplastics, pH, and CBZ solution concentration, on the adsorption of CBZ by MCNTs and MCNTs-PE were thoroughly investigated. The adsorption rate of CBZ by MCNTs decreased from 97.4% to 90.6% as the PE microplastics dose increased from 2 g/L to 20 g/L. This decrease occurred because the MCNTs were coated on the surface of the PE microplastics, which further decreased the effective adsorption area of the MCNTs. This research provides a framework for revealing the effect of microplastics on the adsorption of pollutants by carbon materials in aqueous environments.
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Numerical Investigation of Mixing by Induced Electrokinetic Flow in T-Micromixer with Conductive Curved Arc Plate. Symmetry (Basel) 2021. [DOI: 10.3390/sym13060915] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mixing is essential in microdevices. Therefore, increasing the mixing efficiency has a significant influence on these devices. Using conductive obstacles with special geometry can improve the mixing quality of the micromixers. In this paper, a numerical study on the mixing caused by an induced-charge electrokinetic micromixer was carried out using a conductive plate with a curved arc shape instead of a conductive flat plate or other non-conductive obstacles for Newtonian fluids. This study also explored the effect of the different radius curves, span length, the number of curved arc plates in the channel, the pattern of arrangement, concavity direction, and the orientation angle against the flow on the mixing. Furthermore, the efficiency of the T-micromixer against a flow with a low diffusion coefficient was investigated. It should be noted that the considered channel is symmetric regarding to the middle horizontal plane and an addition of flat plate reflects a formation of symmetric flow structures that do not allow to improve the mixture process. While an addition of non-symmetric curved arc plates al-lows to increase the mixing by creating vortices. These vortices were created owing to the non-uniform distribution of induced zeta potential on the curved arc plate. A rise in the span length of the curved arc plate when the radius was constant improved the mixing. When three arc plates in one concavity direction were used, the mixing efficiency was 91.86%, and with a change in the concavity direction, the mixing efficiency increased to 95.44%. With a change in the orientation angle from 0 to 25, the mixing efficiency increased by 19.2%.
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Guo W, Tang L, Zhou B, Fung Y. Fundamental Studies of Rapidly Fabricated On-Chip Passive Micromixer for Modular Microfluidics. MICROMACHINES 2021; 12:153. [PMID: 33557366 PMCID: PMC7914446 DOI: 10.3390/mi12020153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/16/2021] [Accepted: 02/02/2021] [Indexed: 12/17/2022]
Abstract
Micromixers play an important role in many modular microfluidics. Complex on-chip mixing units and smooth channel surfaces ablated by lasers on polymers are well-known problems for microfluidic chip fabricating techniques. However, little is known about the ablation of rugged surfaces on polymer chips for mixing uses. This paper provides the first report of an on-chip compact micromixer simply, easily and quickly fabricated using laser-ablated irregular microspheric surfaces on a polymethyl methacrylate (PMMA) microfluidic chip for continuous mixing uses in modular microfluidics. The straight line channel geometry is designed for sequential mixing of nanoliter fluids in about 1 s. The results verify that up to about 90% of fluids can be mixed in a channel only 500 µm long, 200 µm wide and 150 µm deep using the developed micromixer fabricating method under optimized conditions. The computational flow dynamics simulation and experimental result agree well with each other.
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Affiliation(s)
- Wenpeng Guo
- First Affiliated Hospital of Shenzhen University, Shenzhen 518035, China;
| | - Li Tang
- The University of Hong Kong, Hong Kong, China; (L.T.); (Y.F.)
| | - Biqiang Zhou
- First Affiliated Hospital of Shenzhen University, Shenzhen 518035, China;
| | - Yingsing Fung
- The University of Hong Kong, Hong Kong, China; (L.T.); (Y.F.)
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Analysis of the Parameters Required to Properly Define Nanofluids for Heat Transfer Applications. FLUIDS 2021. [DOI: 10.3390/fluids6020065] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nanofluids are obtained by dispersing nanoparticles and dispersant, when present, in a base fluid. Their properties, in particular their stability, however, are strictly related to several other parameters, knowledge of which is important to reproduce the nanofluids and correctly interpret their behavior. Due to this complexity, the results appear to be frequently unreliable, contradictory, not comparable and/or not repeatable, in particular for the scarcity of information on their preparation. Thus, it is essential to define what is the minimum amount of information necessary to fully describe the nanofluid, so as to ensure the possibility of reproduction of both their formulation and the measurements of their properties. In this paper, a literature analysis is performed to highlight what are the most important parameters necessary to describe the configuration of each nanofluid and their influence on the nanofluid’s properties. A case study is discussed, analyzing the information reported and the results obtained for the thermophysical properties of nanofluids formed by water and TiO2 nanoparticles. The aim is to highlight the differences in the amount of information given by the different authors and exemplify how results can be contradictory. A final discussion gives some suggestions on the minimum amount of information that should be given on a nanofluid to have the possibility to compare results obtained for similar nanofluids and to reproduce the same nanofluid in other laboratories.
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Numerical Study of T-Shaped Micromixers with Vortex-Inducing Obstacles in the Inlet Channels. MICROMACHINES 2020; 11:mi11121122. [PMID: 33352968 PMCID: PMC7766108 DOI: 10.3390/mi11121122] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/13/2020] [Accepted: 12/15/2020] [Indexed: 01/12/2023]
Abstract
To enhance fluid mixing, a new approach for inlet flow modification by adding vortex-inducing obstacles (VIOs) in the inlet channels of a T-shaped micromixer is proposed and investigated in this work. We use a commercial computational fluid dynamics code to calculate the pressure and the velocity vectors and, to reduce the numerical diffusion in high-Peclet-number flows, we employ the particle-tracking simulation with an approximation diffusion model to calculate the concentration distribution in the micromixers. The effects of geometric parameters, including the distance between the obstacles and the angle of attack of the obstacles, on the mixing performance of micromixers are studied. From the results, we can observe the following trends: (i) the stretched contact surface between different fluids caused by antisymmetric VIOs happens for the cases with the Reynolds number (Re) greater than or equal to 27 and the enhancement of mixing increases with the increase of Reynolds number gradually, and (ii) the onset of the engulfment flow happens at Re≈125 in the T-shaped mixer with symmetric VIOs or at Re≈140 in the standard planar T-shaped mixer and results in a sudden increase of the degree of mixing. The results indicate that the early initiation of transversal convection by either symmetric or antisymmetric VIOs can enhance fluid mixing at a relatively lower Re.
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Wang G, Zhang Z, Wang R, Zhu Z. A Review on Heat Transfer of Nanofluids by Applied Electric Field or Magnetic Field. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E2386. [PMID: 33260487 PMCID: PMC7760193 DOI: 10.3390/nano10122386] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/17/2020] [Accepted: 11/25/2020] [Indexed: 12/27/2022]
Abstract
Nanofluids are considered to be a next-generation heat transfer medium due to their excellent thermal performance. To investigate the effect of electric fields and magnetic fields on heat transfer of nanofluids, this paper analyzes the mechanism of thermal conductivity enhancement of nanofluids, the chaotic convection and the heat transfer enhancement of nanofluids in the presence of an applied electric field or magnetic field through the method of literature review. The studies we searched showed that applied electric field and magnetic field can significantly affect the heat transfer performance of nanofluids, although there are still many different opinions about the effect and mechanism of heat transfer. In a word, this review is supposed to be useful for the researchers who want to understand the research state of heat transfer of nanofluids.
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Affiliation(s)
| | | | - Ruijin Wang
- School of Mechanical Engineering, Hangzhou Dianzi University, Hangzou 310000, China; (G.W.); (Z.Z.)
| | - Zefei Zhu
- School of Mechanical Engineering, Hangzhou Dianzi University, Hangzou 310000, China; (G.W.); (Z.Z.)
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Use of Heavy Metal Content and Modified Water Quality Index to Assess Groundwater Quality in a Semiarid Area. WATER 2020. [DOI: 10.3390/w12041115] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Groundwater is a major source of drinking and agricultural water supply in arid and semiarid regions. Poor groundwater quality can be a threat to human health especially when it is combined with hazardous pollutants like heavy metals. In this study, an innovative method involving entropy weighted groundwater quality index for both physicochemical and heavy metal content was used for a semiarid region. The entropy weighted index was used to assess the groundwater’s suitability for drinking and irrigation purposes. Thus, groundwater from 19 sampling sites was used for analyses of physicochemical properties (electrical conductivity—EC, pH, K+, Ca2+, Na+, SO42−, Cl−, HCO3−, TDS, NO3−, F−, biochemical oxygen demand—BOD, dissolved oxygen—DO, and chemical oxygen demand—COD) and heavy metal content (As, Ca, Sb, Se, Zn, Cu, Ba, Mn, and Cr). To evaluate the overall pollution status in the region, heavy metal indices such as the modified heavy metal pollution index (m-HPI), heavy metal evaluation index (HEI), Nemerow index (NeI), and ecological risks of heavy metals (ERI) were calculated and compared. The results showed that Cd concentration plays a significant role in negatively affecting the groundwater quality. Thus, three wells were classified as poor water quality and not acceptable for drinking water supply. The maximum concentration of heavy metals such as Cd, Se, and Sb was higher than permissible limits by the World Health Organization (WHO) standards. However, all wells except one were suitable for agricultural purposes. The advantage of the innovative entropy weighted groundwater quality index for both physicochemical and heavy metal content, is that it permits objectivity when selecting the weights and reduces the error that may be caused by subjectivity. Thus, the new index can be used by groundwater managers and policymakers to better decide the water’s suitability for consumption.
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Tlili I, Ramzan M, Kadry S, Kim HW, Nam Y. Radiative MHD Nanofluid Flow over a Moving Thin Needle with Entropy Generation in a Porous Medium with Dust Particles and Hall Current. ENTROPY (BASEL, SWITZERLAND) 2020; 22:E354. [PMID: 33286128 PMCID: PMC7516827 DOI: 10.3390/e22030354] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/05/2020] [Accepted: 03/09/2020] [Indexed: 12/19/2022]
Abstract
This paper investigated the behavior of the two-dimensional magnetohydrodynamics (MHD) nanofluid flow of water-based suspended carbon nanotubes (CNTs) with entropy generation and nonlinear thermal radiation in a Darcy-Forchheimer porous medium over a moving horizontal thin needle. The study also incorporated the effects of Hall current, magnetohydrodynamics, and viscous dissipation on dust particles. The said flow model was described using high order partial differential equations. An appropriate set of transformations was used to reduce the order of these equations. The reduced system was then solved by using a MATLAB tool bvp4c. The results obtained were compared with the existing literature, and excellent harmony was achieved in this regard. The results were presented using graphs and tables with coherent discussion. It was comprehended that Hall current parameter intensified the velocity profiles for both CNTs. Furthermore, it was perceived that the Bejan number boosted for higher values of Darcy-Forchheimer number.
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Affiliation(s)
- Iskander Tlili
- Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City 758307, Vietnam;
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 758307, Vietnam
| | - Muhammad Ramzan
- Department of Computer Science, Bahria University, Islamabad Campus, Islamabad 44000, Pakistan
| | - Seifedine Kadry
- Department of Mathematics and Computer Science, Faculty of Science, Beirut Arab University, Beirut 115020, Lebanon;
| | - Hyun-Woo Kim
- Department of ICT Convergence Rehabilitation Engineering, Soonchunhyang University, Asan 31538, Korea;
| | - Yunyoung Nam
- Department of Computer Science and Engineering, Soonchunhyang University, Asan 31538, Korea
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Adsorption of Lead and Nickel on to Expanded Graphite Decorated with Manganese Oxide Nanoparticles. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9245375] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In this study, expanded graphite (EG) was decorated with manganese oxide nanoparticles (MONPs) by the hydrothermal method, and the newly formed composite (MONPs-EG) was applied as adsorbent for the removal of heavy metals from aqueous solutions. The comparative and competitive adsorption of Pb2+ and Ni2+ (0.01–1.00 mM) on MONPs-EG was investigated. Data from isothermal adsorption of single and binary systems suggested that both Pb2+ and Ni2+ were well described by the Langmuir isotherm, and the maximum adsorption capacities at 298 K were calculated at 0.278 and 0.113 mmol/g for Pb2+ and Ni2+, respectively. In binary systems, a dramatic decrease in adsorption capacity of Ni2+ was observed, while the adsorption capacity of Pb2+ was almost stable, indicating the favorable adsorption of Pb2+ over Ni2+ onto the prepared adsorbent. Kinetics studies of single and binary systems showed that a pseudo-second order model could explain the adsorption processes well. Thermodynamic analysis results demonstrated that the adsorption of these metal ions on the prepared adsorbent is spontaneous and exothermic in nature. The adsorption capacity of MONPs-EG increased significantly in the presence of humic acids. Overall, the results of this study suggest that MONPs-EG can be used effectively as an adsorbent for heavy metals removal from aqueous solutions.
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