Microsystems & Nanoengineering
·
2023
·Vol. 9
·期 1
·1-13
·
IF 7.9
Huang Biao,Ge Xinjin,Rubinstein Boris Y.,Chen Xianchun,Wang Lu,Xie Huiying,Leshansky Alexander M.,Li Zhenzhen
Micron- and submicron-sized droplets have extensive applications in biomedical diagnosis and drug delivery. Moreover, accurate high-throughput analysis requires a uniform droplet size distribution and high production rates. Although the previously reported microfluidic coflow step-emulsification method can be used to generate highly monodispersed droplets, the droplet diameter ( d ) is constrained by the microchannel height ( b ), \(d\gtrsim 3b\) , while the production rate is limited by the maximum capillary number of the step-emulsification regime, impeding emulsification of highly viscous liquids. In this paper, we report a novel, gas-assisted coflow step-emulsification method, where air serves as the innermost phase of a precursor hollow-core air/oil/water emulsion. Air gradually diffuses out, producing oil droplets. The size of the hollow-core droplets and the ultrathin oil layer thickness both follow the scaling laws of triphasic step-emulsification. The minimal droplet size attains \(d\approx 1.7b\) , inaccessible in standard all-liquid biphasic step-emulsification. The production rate per single channel is an order-of-magnitude higher than that in the standard all-liquid biphasic step-emulsification and is also superior to alternative emulsification methods. Due to low gas viscosity, the method can also be used to generate micron- and submicron-sized droplets of high-viscosity fluids, while the inert nature of the auxiliary gas offers high versatility.
研究领域:
生物医学工程
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2020
·
IF 3.871
Ya-Ni Ji,Wen-Jie Geng,Chun-Yang Ma,Jing Tan,Wen-Sheng Deng,Bin Liu,Yue-Feng Su
A simple and effective method was conducted for preparing microdispersed droplets with decreased size and increased uniformity, in which phase inversion in high-phase-ratio liquid/liquid system was combined with addition of microbubbles. Five typical flow patterns were observed, including W/O, O/W/O, transition regime, O/W and G/W/O regimes. Flow regime transition was observed, according to which physical properties of systems and operating conditions for preparing single-oil-droplet-in-water emulsion were determined in different liquid/liquid and gas/liquid/liquid modes. Effects of liquid viscosities as well as interfacial tension on droplet size ( D O ) and its standard deviation (SD) were studied systematically and the most effective gas/liquid/liquid mode was recommended. Mathematical models were established for correlating D O in five different modes, which show relatively good agreement with experimental results. D O decreases by 42% via introducing phase inversion and further reduces to 25% by addition of microbubbles, both under the same operating conditions.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Applied Sciences-Basel
·
2021
·Vol. 11
·期 16
·7258
·
IF 2.679
Qi Liu,Shengde Chen,Guobin Wang,Yubin Lan
Background: Unmanned Aerial Vehicles (UAVs) applied to agricultural plant protection is widely used, and the field of operation is expanding due to their high efficiency and pesticide application reduction. However, the work on pesticide drift lags behind the development of the UAV spraying device. Methods: We compared the spray drift potential at four liquid pressures of 2, 3, 4, and 5 bar ejected from the hydraulic nozzles mounted on a UAV test platform exposed to different wind speeds of 2, 4, and 6 m/s produced by a wind tunnel. The combination of the wind tunnel and the UAV test platform was used to obtain strict test conditions. The droplet size distribution under spray drift pressures was measured by a laser diffraction instrument. Results: Increasing the pressure leads to smaller droplet volume diameters and produced fine droplets of less than 100 µm. The deposition in the drift area was elevated at most of the sampling locations by setting higher pressure and faster wind speed. The deposition ratios were all higher than the flow ratios under three wind speeds after the adjustment of pressures. For most samples within a short drift distance (2–8 m), the drift with the rotor motor off was more than an order of magnitude higher than that with the rotor motor on at a pressure of 3 bar. Conclusions: In this study, the wind speed and liquid pressure all had a significant effect on the UAV spray drift, and the rotor wind significantly inhibited a large number of droplets from drifting further.Keywords:unmanned aerial vehicle;liquid pressure;drift deposition;wind speed;rotor wind field;droplet size
研究领域:
农业工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Chemistry & Engineering
·
2022
·Vol. 7
·期 11
·2322-2333
·
IF 5.2
Jing Song,Chencan Du,Junjie Wang,Yongjin Cui,Yujun Wang,Jian Deng,Guangsheng Luo
Microreaction technology provides a powerful tool for reactions under extreme conditions, but the micro-dispersion performance of those processes under real reaction conditions is hard to visualize. Therefore, we constructed a novel observation platform by placing the downstream observation window vertically. We successfully achieved the accurate measurement of droplets ranging in size from microns to millimeters for real reaction systems in a T-junction microdevice, and proved that the droplet coalescence can be avoided at the outlet of the microreactor. The actual micro-dispersion state of different types of systems can be exactly reflected in the observation window. We further investigated the effect of shearing routes on the droplet size in toluene nitration by using this platform and provided design guidance on the choice of shearing routes for nitration. The scaling laws under different shearing routes have been established based on the obtained micro-dispersion data in this work. This work has promoted the connection of fundamental research studies with real applications of microreaction technology, which is critical for the future development of microreaction technology.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Yu Xie,Guoming Huang,Weiguo Hu,Yujun Wang
Piperacillin is a polar organic substance, and can reduce the interfacial tension of oil and water when dissolved in water. In this study, changes in dichloromethane–water interfacial tensions and microdroplet sizes during piperacillin synthesis from an aqueous solution of ampicillin and dichloromethane solution of 4-ethyl-2,3-dioxo-1-piperazine carbonyl chloride (EDPC) were observed using a pendent drop technique and a coaxial ring tube system with embedded high-speed camera, respectively. It was found that the rapid N -acylation reaction caused the piperacillin at the interface to synthesize rapidly and diffuse out slowly, resulting in the interfacial tension decreased from 19.5 mN·m −1 to 7.2 mN·m −1 rapidly and then increased slowly as the concentrations of ampicillin and EDPC were 0.05 mol·L −1 and 0.1 mol·L −1 . Meanwhile, the increase in the concentration of EDPC increased the peak concentration of piperacillin at the interface, and the addition of ethyl acetate to the ampicillin solution promoted mass transfer and reduced the aggregation of piperacillin effectively. During synthesis, the interfacial tension decreased, leading to a change in droplet sizes in the micro-reaction system. The two-phase reaction was carried out in a coaxial ring tube, with ampicillin and EDPC solutions as continuous and dispersed phases, respectively. The reaction reduced the dripping flow area, and the addition of ethyl acetate to the ampicillin solution slightly affected the division of the flow pattern. Under the same flow conditions, the droplet sizes of the reaction group were smaller than those of the no reaction group. The experimental results demonstrated that the increase of the continuous phase, decrease in the dispersed phase flow rate, or increase in EDPC concentration making droplet sizes smaller, and the addition of ethyl acetate slightly affected droplet sizes. These findings are important for the design and optimization of piperacillin synthesis reactors.
研究领域:
化学工程
·
制药工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Lu Qi,Xianghai Meng,Rui Zhang,Haiyan Liu,Chunming Xu,Zhichang Liu,Peter A.A. Klusener
Droplet size distribution (DSD) and mean droplet size of chloroaluminate ionic liquid (IL)–heptane dispersion in a stirred vessel were investigated as a model system for the composite ionic liquid/hydrocarbon system applied in the commercial isobutane alkylation process. Focused beam reflectance measurement was used to identify the phase inversion, and particle video microscope (PVM) was employed to measure the DSD of IL-continuous dispersions. The effects of agitation speed and dispersed phase holdup on the DSD and mean droplet size were investigated. Phase inversion was found at a heptane hold-up of just above 0.5. The observed DSDs could be described well by logarithmic normal distributions in spite of variable operating conditions. The DSDs appeared to be more or less independent of the dispersed phase holdup ( ϕ heptane ⩾ 0.3) at the same agitation speed. A semi-empirical correlation based on Shinnar theory was proposed to predict the droplet mean size in the impeller region for the IL-continuous dispersion, and the predicted value agreed well with the experimental data. This work will be a good basis to predict the dispersion behavior under process conditions.
研究领域:
化学工程
·
流体力学
·
多相系统
·
过程工程
·
胶体与界面科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Yuqiang Mao,Peilun Shen,Liuyang Dong,Xingcai Yu,Guangyuan Xie,Yijiang Li,Han Wang,Wencheng Xia,Dianwen Liu
The dynamic pore wetting plays a vital role in the flotation separation process of porous mineral particles, such as low-rank coal, fly ash and chrysocolla, etc. This paper investigated the dynamic pore wetting behavior of active carbon particles in the water-oil emulsion by 1 H low-field nuclear magnetic resonance ( 1 H LF-NMR). The influence of oil droplet size on pore wetting process was revealed. The change in the surface properties of particles before and after wetting was analyzed by contact angle and FTIR measurements. The particle-bubble attachment process in the emulsion and pure water was compared. The total pore wetting percentage of active carbon had a first-order kinetic relationship with the wetting time. The emulsion was beneficial to decrease the pore wetting percentage of particles compared with water. And the pore wetting percentage decreased with the decrease of oil droplet size in emulsion. The pores were easily filled by the oil droplet with small size and the hydrophobicity of sample surface was improved, which prevented the subsequent pore wetting by water. As a result, the detachment force of particle-bubble was increased with the help of micro-oil droplets. This work attempts to provide a new inspiration for the study of porous mineral flotation.
研究领域:
矿物加工工程
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2022
·Vol. 68
·期 6
·e17659
·
IF 4.167
Boren Tan,Ziyang Xu,Yong Wang,Yanlin Zhang,Yongqi Hu,Tao Qi
The dispersed phase holdup and drop size in solvent extraction columns vary along the column height and this affects the mass transfer coefficient and interfacial area. In this article, mass transfer study was performed experimentally using a 25 mm diameter agitated pulsed column. The axial distribution of mass transfer coefficient was determined by coupling population balance equation and axial dispersion model by taking the longitudinal variation in hydrodynamic performance into consideration. Feasibility of different mass transfer models in predicting concentration profiles was evaluated and a novel correlation based on effective diffusivity was developed. The results showed that both overall and volumetric mass transfer coefficients have significant change along the column height and greatly depends on the agitation speed and pulsation intensity. Increasing dispersed phase velocity also augments the overall mass transfer coefficient. The maximum number of transfer unit was measured to be 10 m −1 at agitation speed of 1000 rpm.
研究领域:
化学工程
·
传质动力学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2024
·
IF 8.1
Hao Sun,Xiaobing Li
In the alkaline-surfactant-polymer flooding emulsion, oil droplets with various sizes exhibited different interfacial properties , resulting in different stabilization and destabilization behaviors. In view of this, it is expected to achieve outstanding oil-water separation efficiency by screening targeted demulsifier for oil droplets with different size ranges (0–1, 1–5 and 5–10 μm). Based on the size effect of oil droplets, a series of multibranched polyether-polyquaternium demulsifiers that integrated different charge neutralization and interfacial displacement functionalities were designed by regulating the cationicity and EO:PO ratios. As a result, the most effective polyether-polyquaternium variant for each size range of oil droplet was screened out. By employing these three selected polyether-polyquaternium variants in a sequential batch demulsification test, the maximum demulsification efficiency of 95.1% was obtained, which was much higher than that using a single polyether-polyquaternium variant (82.5%, 80.5% and 83.8%). The adsorption behaviors of polyether-polyquaternium variants on the oil/water interface were investigated by the molecular dynamics simulation. Moreover, the interfacial properties and oil droplet size variations during the demulsification process were monitored, so as explore the demulsification mechanism. This demulsification protocol based on the size effect of oil droplets with its excellent oil-water separation performance offered significant technical promise for the emulsified oil wastewater disposal.
研究领域:
石油工程
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LIQUID CRYSTALS
·
2020
·
IF 2.908
Gang Hu,Hongxiang Chen,Zhiqiang Liu,Song Zhang,Yu Zhou,Bailin Zhu,Huazhi Gu
To improve the electro-optical properties of polymer-dispersed liquid crystal (PDLC) film, the size and number of liquid crystal droplets were regulated by changing component, curing method, curing temperature and time, and so on, but the regulation reported in the literatures was constrained within the curing process. In this work, the size of liquid crystal droplets is regulated by quenching around the glass transition temperature (Tg) at which the mobility of polymer chains changes dramatically. At the same time, the degree of supersaturation of liquid crystal molecules changes due to the decrease of temperature, thereby regulating the number of nucleation of liquid crystal droplets. Through the study of the above process, the effects of the size and number of liquid crystal droplets and the content of liquid crystal dissolved in the polymer network on the electro-optical properties of PDLC film are discussed. The research provides a new method to regulate the structure and properties of PDLC film aiming at the cured PDLC film, effectively overcoming the disadvantage of the regulation aiming at the curing process.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Xinyi Li,Shuchun Zhao,Junheng Guo,Wei Li,Jinli Zhang
For industrial emulsification processes, it remains a challenge to obtain desirable droplet size distribution (DSD) as well as a smaller span via facile and efficient routes. In this work, a novel blind-side rotor is designed to assemble with the stator of a laboratory-scale inline high-shear mixer equipped with an annular cylinder inside the mixing chamber (bRS HSM). The effects of operating parameters, structural parameters on the average droplet size, DSD, and span are experimentally investigated and compared with those of commercially used toothed-type rotor-stator assembly. In addition, computational fluid dynamics calculations are performed to investigate the influences on the flow field of the fluid within the HSM. The results show that the structure of the bRS HSM not only generates an optimal span but also reduces the energy consumption of the mixer, which is more advantageous for production of emulsions with narrower DSD. In the bRS HSM, Sauter mean diameter (d32) and span decrease with increasing rotor speed but decreasing flow rate of the continuous phase, while span decreases and then increases with increasing volume fraction of the dispersed phase. Meanwhile, the effect of structural parameters on span is nonmonotonic. Furthermore, the artificial neural network (ANN) model is used to perform the correlation of d32 and span, providing an estimation method to optimize the operating and structural parameters of the inline HSM in the emulsification process.
研究领域:
化学工程
·
过程工程
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
FOOD HYDROCOLLOIDS
·
2023
·
IF 10.7
Yue Dong,Zihao Wei,Changhu Xue
The effect of interaction between ovotransferrin fibrils (OVTFs) and citrus pectin (CP) on the properties of oleogel-based Pickering emulsions was innovatively explored. Firstly, the interaction between OVTFs and CP was investigated by constructing OVTF–CP complexes. OVTF–CP complexes with better stability were obtained when OVTFs to CP mass ratio of 3:1 at pH 5.0, which exhibited pearl chain-like structures by electrostatic attractions. Subsequently, to discuss the effect of interaction between OVTFs and CP on the properties of oleogel-based Pickering emulsions, oleogel-based OVTF-stabilized Pickering emulsion (OE) and oleogel-based OVTF–CP complex-stabilized Pickering emulsion (OCPE) were developed. The interaction between OVTFs and CP endowed OCPE with better stability, smaller droplet size, more prominent gel-like structure, higher viscosity and superior texture properties compared with OE. To construct an efficient delivery system for nutraceuticals, OE and OCPE were used to load curcumin . Compared with curcumin-loaded OE, curcumin-loaded OCPE had excellent protection for curcumin, higher rate of lipolysis and bioaccessibility of curcumin. Our work demonstrates that the interaction between OVTFs and CP can regulate the properties of oleogel-based Pickering emulsions, which will provide new insights into the formation and application of protein fibril–polysaccharide complexes. This may contribute to the precise development of Pickering emulsions with protein fibril–polysaccharide structures and ideal properties.
研究领域:
食品科学
·
胶体科学
·
营养保健品
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）