Nanomaterials
·
2018
·Vol. 8
·期 11
·918
·
IF 3.504
Dan Tian,Chun-Hui He,Ji-Huan He
Electrospinning is now commercially used for the fabrication of nano/micro fibers. Compared with spider dragline silk, artificial fibers have poor mechanical properties. Unlike natural silk, which has a hierarchical structure with an approximate 3-fold symmetry, the molecular structure of spun fiber has neither folding nor orientation. To date, it is almost impossible to control molecule orientation during the spinning process. Here, we show that macromolecule orientation can be easily controlled using the laminar flow of fluid mechanics. A lasting laminar flow in a long needle can order macromolecules. We find that the orientation of macromolecules can greatly affect the morphology and mechanical properties of fibers. We expect our technology to be helpful for more sophisticated fabrication of fibers with ordered macromolecules and DNA-like twists.Keywords:macromolecule;laminar flow;electrospinning;hierarchical structure
研究领域:
材料科学
·
生物物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Qichen Shang,Daiwei Gu,Lin Sheng,Yu Chang,Jian Deng,Guangsheng Luo
Laminar jet flow is an underlying phenomenon used to generate droplets efficiently. However, its hydrodynamics at the microscale remains unknown. This work focuses on the scale effect. We innovatively propose the difference between the jet at the microscale and that at the regular scale is not in the wave development but in the regime of flow pattern, and it’s much more stable at the microscale. The characteristic effect at the microscale due to the intensified gas/liquid/solid–liquid interaction is first reported. The variations of characteristic sizes and hydrodynamics with the kinetic energy, physical property, and structural size at the microscale are analyzed by introducing two key parameters − wave velocity and wave numbers, which are first proposed. The result shows that the kinetic energy determines the hydrodynamics. Viscosity and interfacial tension significantly affect the microscale laminar jet. Using wave numbers, Tyler’s equation is modified, guiding the design of effective microdroplet-generation devices.
研究领域:
流体力学
·
微流控技术
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2020
·
IF 4.57
Geyuan Yin,Qunfei Gao,Erjiang Hu,Jiawei Xu,Meng Zhou,Zuohua Huang
Laminar flame speeds of formic acid were measured at equivalence ratios of 0.4–1.6, initial temperature of 423–453 K and atmospheric pressure. Chemical kinetic models (Glarborg model and AramcoMech 3.0) were validated against the present experimental data. Deep kinetic insight was investigated using the present models. In addition, detailed analysis was carried out according to transport, thermal and kinetic effect to find out the totally different performance of these two models. The results show that the simulated laminar flame speeds using Glarborg model match well with experimental data while AramcoMech 3.0 apparently over predicts the laminar flame speeds. HOCO and OCHO are driving species for the laminar flame speed of formic acid. Furthermore, the pathway analysis indicates formic acid is consumed mainly by abstraction reaction with OH, forming OCHO radical, which quickly dissociates to H+CO 2 .
研究领域:
燃烧学
·
化学动力学
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2019
·
IF 4.12
Wei Li,Yan Zhang,Bowen Mei,Yuyang Li,Chuangchuang Cao,Jiabiao Zou,Jiuzhong Yang,Zhanjun Cheng
Flow reactor pyrolysis and laminar flame propagation are investigated for n -propanol and i -propanol, which are the smallest alcohol fuels with isomeric structures. Pyrolysis products of propanol isomers at 0.04–1 atm are detected using the synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). Experimental observations demonstrate ethylene and propene are respective dominant hydrocarbon products in the n -propanol and i -propanol pyrolysis, while the most abundant oxygenated products are formaldehyde, acetaldehyde and ethenol in the n -propanol pyrolysis and acetone and acetaldehyde in the i -propanol pyrolysis. Higher concentrations of aromatic and oxygenated pollutants are observed in the i -propanol pyrolysis. The laminar burning velocities of propanol isomers are measured in a high-pressure constant-volume cylindrical combustion vessel at the initial temperature of 423 K, pressures of 1–10 atm and equivalence ratios of 0.6–1.5. A general trend that n -propanol has much faster LBVs than i -propanol is noticed under all investigated conditions. A kinetic model of propanol isomers is developed and validated against the present experimental data, as well as other experimental data in literature covering wide ranges of temperatures, pressures and equivalence ratios. Rate of production analysis and sensitivity analysis are performed together to provide insight into the fuel isomeric effects on key reaction pathways and fuel reactivities. In the flow reactor pyrolysis, different dominant primary decomposition pathways of n -propanol and i -propanol lead to the differences in both molecular structures and concentration levels of pyrolysis products. In laminar flame propagation, different radical pool distributions of propanol isomers are illustrated and found to be largely influenced by fuel isomeric structures. The linear structure of n -propanol promotes the formation of more active radicals like formyl, vinyl and ethyl, while the branched structure of i -propanol facilitates the production of more stable radicals including methyl and allyl. Thus, the promoted chain-branching in n -propanol flames and enhanced chain-termination in i -propanol flames can explain the higher laminar burning velocities and reactivities of n -propanol than that of i -propanol.
研究领域:
化学工程
·
燃烧科学
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2022
·
IF 5.767
Yan Zhang,Chuangchuang Cao,Bowen Mei,Jiabiao Zou,Long Zhao,Jiuzhong Yang,Yuyang Li
This work investigated the flow reactor pyrolysis of n -pentylbenzene using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) at 0.04 and 1 atm, and measured the laminar burning velocities (LBVs) of n -pentylbenzene in a high-pressure constant-volume cylindrical combustion vessel at 473 K, 1–10 atm and equivalence ratios ( ϕ ) of 0.7–1.5. A kinetic model of n -pentylbenzene combustion was developed from our previous models of n -butylbenzene and validated against the present experimental data. The unimolecular decomposition reactions and H-abstraction reactions are the dominant consumption pathways of n -pentylbenzene under pyrolysis conditions. Aromatic intermediates with unsaturated side-chains play crucial roles in indene and naphthalene formation, while phenyl and benzyl are precursors of unfused polycyclic aromatic hydrocarbons (PAHs) which in turn convert to fused tricyclic PAHs. In the laminar flame propagation, small species reactions are crucial under lean conditions, while chain-termination reactions, especially fuel-specific reactions, show important inhibition effects on the laminar flame propagation under rich conditions. Furthermore, the effects of side-chain length on the pyrolysis and laminar flame propagation of alkylbenzenes were also investigated for toluene, ethylbenzene , n -propylbenzene, n -butylbenzene and n -pentylbenzene. It is concluded that alkylbenzene smaller than n -butylbenzene tends to decompose at low temperature as the side-chain length increases, while n -butylbenzene and n -pentylbenzene have very close decomposition temperature regions. For indene and naphthalene formation, decomposition/cyclization reaction sequences of C 9 and C 10 alkenylbenzenes have rapidly increasing importance in the pyrolysis of large alkylbenzenes. Benzyl is concluded to play an important role in inhibiting laminar flame propagation of alkylbenzenes, which is an important reason for the observations that toluene and ethylbenzene have the lowest and highest LBVs, respectively.
研究领域:
化学工程
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
Micromachines
·
2023
·Vol. 14
·期 7
·1277
·
IF 3.4
Chuang Wu,Haithm Yahya Mohammed Almuaalemi,A. S. M. Muhtasim Fuad Sohan,Binfeng Yin
Gel fibers prepared based on microfluidic laminar flow technology have important research value in constructing biomimetic scaffolds and tissue engineering. The key point of microfluidic laminar flow technology is to find the appropriate fluid flow rate in the micropipe. In order to explore the influence of flow rate on the laminar flow phenomenon of a microfluidic chip, a microfluidic chip composed of an intermediate main pipe and three surrounding outer pipes are designed, and the chip is prepared by photolithography and the composite molding method. Then, a syringe pump is used to inject different fluids into the microtubing, and the data of fluid motion are obtained through fluid dynamics simulation and finite element analysis. Finally, a series of optimal adjustments are made for different fluid composition and flow rate combinations to achieve the fluid’s stable laminar flow state. It was determined that when the concentration of sodium alginate in the outer phase was 1 wt% and the concentration of CaCl2in the inner phase was 0.1 wt%, the gel fiber prepared was in good shape, the flow rate was the most stable, and laminar flow was the most obvious when the flow rate of both was 1 mL/h. This study represents a preliminary achievement in exploring the laminar flow rate and fabricating gel fibers, thus offering significant reference value for investigating microfluidic laminar flow technology.Keywords:microfluidic technology;laminar flow;gel fiber;fluid dynamics;sodium alginate
研究领域:
生物工程
·
组织工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2023
·Vol. 15
·期 13
·2905
·
IF 5
Xiaozhi Ouyang,Cheng Huang,Sha Cheng,Pengchao Zhang,Wen Chen
Ultrathin hydrogel films composed of cross-linked polymer networks swollen by water, with soft and moisturized features similar to biological tissue, play a vital role in flexible biosensors and wearable electronics. However, achieving efficient and continuous fabrication of such films remains a challenge. Here, we present a microfluidic-based strategy for the continuous fabrication of free-standing ultrathin hydrogel films by using laminar flow, which can be precisely controlled in the micrometer scale. Compared with conventional methods, the microfluidic-based method shows advantages in producing hydrogel films with a high homogeneity as well as maintaining the structural integrity, without the need of supporting substrates and sophisticated equipment. This strategy allows the precise control over the thickness of the hydrogel films ranging from 15 ± 0.2 to 39 ± 0.5 μm, by adjusting the height of the microfluidic channels, with predictable opportunities for scaling up. Therefore, our strategy provides a facile route to produce advanced thin polymer films in a universal, steerable, and scalable manner and will promote the applications of thin polymer films in biosensors and wearable electronics.Keywords:microfluidic;laminar flow;ultrathin hydrogel film;continuous fabrication;controlled thickness
研究领域:
材料科学
·
生物医学工程
·
微流控技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Qidan Cai,Huaidong Peng,Jiang Meng,Youshao Yan,Yu Zeng,Paul C.H. Li,Yue Sun
In this study, a three-phase laminar flow microfluidic chip (TPL chip) combined with HPLC was developed for monitoring free and total concentrations of paclitaxel (PTX) in blood simultaneously. A diluted whole blood sample (aqueous phase) was introduced into the chip, ethyl acetate (organic phase) was introduced into the chip for extraction, and an interphase was used to prevent the blood sample from coming into direct contact with the organic phase. Because only free drug can quantitatively diffuse into the organic extraction phase and the free drug fraction has a linear relationship with the dilution factor of blood, both the free and total drug concentrations can be obtained by detecting the concentration of paclitaxel in the organic extraction phase. The governing factor such as flow rate for extraction was optimized. Docetaxel was used as an internal standard. The reliability of the quantitative diffusion of molecules in the TPL chip was proved by the methodological investigation of PTX in PBS sample, which showed a good linearity in the concentration range of 0.5 - 100 µg/mL and a detection limit of 7 ng/mL. Good repeatibilities for retention time (RSD of PTX is 1.23%, docetaxel is 1.14%, n = 5) and peak area ratio of PTX to docetaxel (RSD is 4.38%) were obtained. For blood sample analysis, only 100 µL of sample was needed and whole pretreatment was finished in 35 min, and a recovery of 94~117% were obtained. The provided method showed advantages in fast analysis speed, minimum sample handing, and potential ability of automation, and integration.
研究领域:
分析化学
·
药代动力学
·
生物医学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Yunrui Han,Lin Han,Limin He,Shipeng Wang,Xiaoming Luo
The initial motion of micro-oil droplets on substrates immersed in water is of great significance to study droplet motion. Here, microscopic experiments and mechanism analysis are used to establish a universal criterion and a mathematical model describing the critical conditions for the initial motion of droplets adhered on surfaces with different wettability in the laminar flow. We demonstrate a surface modification technique and analysis method in a microtest. Based on the force’s analysis on the three-phase contact points of two-dimensional oil droplets on the surfaces, the movement mechanism is also obtained when the oil droplets start to move. In addition, this work focuses on the coupling effects of oil droplet’s height, surface properties, and water flow velocity on the initial motion behaviors of oil droplets and obtains the critical shear water flow velocity required for the critical movement of oil droplets from different surfaces. We achieve a universal criterion and model for different application scenarios, which are of great scientific significance to improve theoretical systems of multiphase separation and guide the design and optimization of surface properties and flow field velocity.
研究领域:
物理学
·
流体力学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2019
·
IF 3.683
Yunrui Han,Shipeng Wang,Rifeng Zhou,Limin He,Xiaoming Luo
In this article, the rising trajectories of oil droplets near the substrates of small channels in the laminar flow field were observed using a high-speed camera. Chemical modifications were made on the surfaces of the brass sheets to change the surface properties, and the controllable regulation of the superoleophilic–superoleophobic wettability gradient was achieved. The adhesion behaviors of the oil droplets on surfaces with different wettabilities at different flow velocities were observed as well. According to the adhesion behaviors of oil droplets on surfaces with different wettabilities, a mathematical model was established to analyze water film thinning and the adherence of oil droplets on the wall in the laminar flow field. Then the quantitative relationships among the adhesion times tf of oil droplets on different wetting surfaces, oil and water properties, and surface wettability were acquired.
研究领域:
流体力学
·
材料科学
·
界面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2023
·
IF 3.9
Dongxue Tao,Haitao Zhou,Kaihui Cui,Linchen Xie,Kun Huang
The unique characteristics of the interface environment that distinguish bulk phases can promote or inhibit certain reactions and significantly change chemical reactivity. In this work, the separation of Rh (III) and Fe (III) on the surface of concentrated hydrochloric acid was studied by a thin-layer oil membrane (TOM) extraction based on laminar flow with 18-Crown-6-ether (18C6) as the extractant. A new phenomenon different from conventional extraction was found. The TOM extraction prefers to identify hydrated Rh (III) anions rather than H 3 O + ions at the interface due to a lower concentration of free hydrated hydrogen ions on the surface of concentrated hydrochloric acid. However, during the conventional extraction, the H 3 O + ions in the bulk phase are preferentially extracted by the 18C6, and then the hydrated rhodium (III) anions could be extracted by the protonated crown ether through the ion association mechanism. Besides, it was found that the TOM extraction could enhance extraction of hydrated rhodium (III) anions by taking advantage of the uniqueness of rhodium species on the interface, and by adjusting the thickness of the oil membrane and the flow rate of the aqueous phase . The decrease in the oil membrane thickness and the increase in the flow rate of the aqueous phase are conducive to the complexation of 18C6 with the hydrated rhodium (III) at the interface, which can better reflect the targeting and the controllability of extracting single species of hydrated rhodium (III) ions at the interface. Considering the applications of selective recovery of Rh (III) from concentrated hydrochloric acid leaching solution of waste automobile catalyst, the selective separability of Rh (III) to other coexisting metal impurity ions such as Fe (III), Cu (II), Co (III) and Ni (II), was also evaluated. This work provides a new strategy for preferential recovery and separation of rhodium in concentrated hydrochloric acid leach solutions containing other base metal ions for possible future's application.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS
·
2020
·Vol. 53
·期 1
·154-163
·
IF 1.531
Yuyang Li,Jiabiao Zou,Wenhao Yuan,Chuangchuang Cao,Yan Zhang,Fei Qi,Jiuzhong Yang
This work reports an investigation on laminar premixed flames of tetralin at 30 Torr and equivalence ratios of 0.7 and 1.7. Measurements of the chemical structure including identification and mole fraction measurements of free radicals, isomers, and polycyclic aromatic hydrocarbons (PAHs) were performed using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). A kinetic model with 296 species and 1 577 reactions was developed and validated against the flame chemical structure data measured in this work. Modeling analysis reveals the key reaction pathways in tetralin decomposition and PAHs formation. The H-atom abstraction reactions by H, O, and OH are found to control the consumption of tetralin in the lean flame, while those by H play the dominant role in the rich flame. Indene and naphthalene have very high concentration levels in the rich tetralin flame due to the existence of direct formation pathways from the decomposition of tetralin. The two bicyclic PAHs and their radicals play significant roles in the PAHs growth process of tetralin combustion, which results in the high sooting tendency of tetralin compared to those of alkylbenzenes with smaller or same carbon atom numbers.
研究领域:
化学动力学
·
燃烧科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）