scholarly journals Fabrication of Beltlike Fibers by Electrospinning

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1087 ◽  
Author(s):  
Yan-Qing Liu ◽  
Chun-Hui He ◽  
Xiao-Xia Li ◽  
Ji-Huan He

Electrospinning is always used to fabricate one-dimensional nanofibers. Cylindrical fibers are formed during the spinning process due to the minimal-surface principle. However, when the moving jet has high rigidity, which can counteract the surface tension for a minimal surface, beltlike fibers can be obtained. Using the Hall–Petch effect, the rigidity of the moving jet can be greatly enhanced by adding nanoparticles. Polyethylene glycol with a nanometric crystallite size of 4 nm and ZrO2 nanoparticles are used as additives in the experiment, a theoretical analysis is carried out, and the theoretical predictions are verified experimentally.


2016 ◽  
Vol 20 (3) ◽  
pp. 845-848 ◽  
Author(s):  
Zhong-Fu Ren ◽  
Fang-Zhi Kong ◽  
Fei-Yan Wang ◽  
Gui-Fang Hu

Polymer bubbles are widely used for fabrication of nanofibers. Bubble size affects not only bubble's surface tension, but also fiber's morphology. A mathematical model is established to reveal the effect of bubble size on the spinning process, and the experiment verification shows the theoretical analysis is reliable.



2012 ◽  
Vol 16 (1) ◽  
pp. 327-330 ◽  
Author(s):  
Ji-Huan He

Polymer bubbles can be used to fabrication of nanofibers using the bubble electrospinning, temperature is one of the most effective parameters to control the spinning process. Suitable choice of inner and outer temperatures results in a minimal surface tension. A bubble under electronic field will be broken to form daughter bubble cascades, which can be used for nanofiber fabrication.



1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.



2020 ◽  
Vol 83 (1) ◽  
pp. 91-114
Author(s):  
Adrian Blau

AbstractThis paper proposes a new framework for categorizing approaches to the history of political thought. Previous categorizations exclude much research; political theory, if included, is often caricatured. And previous categorizations are one-dimensional, presenting different approaches as alternatives. My framework is two-dimensional, distinguishing six kinds of end (two empirical, four theoretical) and six kinds of means. Importantly, these choices are not alternatives: studies may have more than one end and typically use several means. Studies with different ends often use some of the same means. And all studies straddle the supposed empirical/theoretical “divide.” Quentin Skinner himself expertly combines empirical and theoretical analysis—yet the latter is often overlooked, not least because of Skinner's own methodological pronouncements. This highlights a curious disjuncture in methodological writings, between what they say we do, and what we should do. What we should do is much broader than existing categorizations imply.



1969 ◽  
Vol 24 (10) ◽  
pp. 1449-1457
Author(s):  
H. Klingenberg ◽  
F. Sardei ◽  
W. Zimmermann

Abstract In continuation of the work on interaction between shock waves and magnetic fields 1,2 the experiments reported here measured the atomic and electron densities in the interaction region by means of an interferometric and a spectroscopic method. The transient atomic density was also calculated using a one-dimensional theory based on the work of Johnson3 , but modified to give an improved physical model. The experimental results were compared with the theoretical predictions.



The direct correlation function between two points in the gas-liquid surface of the penetrable sphere model is obtained in a mean-field approximation. This function is used to show explicitly that three apparently different ways of calculating the surface tension all lead to the same result. They are (1) from the virial of the intermolecular potential, (2) from the direct correlation function, and (3) from the energy density. The equality of (1) and (2) is shown analytically at all temperatures 0 < T < T c where T c is the critical temperature; the equality of (2) and (3) is shown analytically for T ≈ T c , and by numerical integration at lower temperatures. The equality of (2) and (3) is shown analytically at all temperatures for a one-dimensional potential.



2017 ◽  
Vol 896 ◽  
pp. 167-174 ◽  
Author(s):  
Zhi Yuan Yang ◽  
Zhuo Yue Meng ◽  
Zhi Hua Li ◽  
Si Tong Wang

Polyethylene glycol (PEG-200) and itaconic acid (IA) were used as raw materials to compound macromer through esterification reaction. A new type of specialized water-coke slurry dispersant was synthesized by copolymerization of microware, sodium methallyl sulfonate (SMAS) and maleic anhydride (MA). The experiment showed that the concentration of slurry could be reached to 63% with the dosage of 0.2%, and the apparent viscosity was 1140.3 mPa∙s. Through the analysis of the infrared, the dispersant was confirmed to have polyethylene glycol branched chain and hydrophilic functional groups such as carboxyl or sulfonic group. When the concentration of dispersant was 30 g/L, the surface tension of water could be decreased from 72.70 mN/m to 45.50 mN/m. Furthermore, when the solution pH value was 9, the Zeta potential of semi-coke powder surface could also be decreased from-13.38 mV to-25 mV with the addition of dispersant. Thus, this dispersant could increase electronegativity of semi-coke powder surface, enhance steric-hindrance effect and prevent the phenomenon of powder flocculation and gather. Meantime, it also could reinforce the semi-coke hydrophilic by reducing the surface tension of water effectively. And then, the high performance water-coke slurry could be obtained.



Author(s):  
Epifanio G. Virga

For nearly two centuries, the dynamics of chains have offered examples of paradoxical theoretical predictions. Here, we propose a theory for the dissipative dynamics of one-dimensional continua with singularities which provides a unified treatment for chain problems that have suffered from paradoxical solutions. These problems are duly solved within the present theory and their paradoxes removed—we hope.





2004 ◽  
Vol 4 (6) ◽  
pp. 8627-8676 ◽  
Author(s):  
D. O. Topping ◽  
G. B. McFiggans ◽  
H. Coe

Abstract. A thermodynamic modelling framework to predict the equilibrium behaviour of mixed inorganic salt aerosols is developed, and then coupled with a technique for finding a solution to the Köhler equation in order to create a diameter dependent hygroscopic aerosol model (Aerosol Diameter Dependent Equilibrium Model – ADDEM). The model described here provides a robust and accurate inorganic basis using a mole fraction based activity coefficient model and adjusted energies of formation for treating solid precipitation. The model framework can accommodate organic components, though this added complexity is considered in a companion paper, whereas this paper describes the development of the modelling architecture to be used and predictions of an inorganic model alone. The modelling framework has been developed to flexibly use a combination of mixing rules and other potentially more accurate techniques where available to calculate the water content. Comparisons with other state-of-the-art general equilibrium models and experimental data are presented and show excellent agreement. The Kelvin effect can be considered in this scheme using a variety of surface tension models. Comparison of predicted diameter dependent phenomena, such as the increased relative humidity for onset of deliquescence with decreasing diameter, with another diameter dependent model is very good despite the different approach used. The model is subject to various sensitivities. For the inorganic systems studied here, the model is sensitive to choice of surface tension scheme used, which decreases for larger aerosol. Large sensitivities are found for the value of dry density used. It is thus likely that the history of the aerosol studied in a hygroscopic tandem differential mobility analyser (HTDMA), specifically the nature of the drying process that will influence the final crystalline form, will create systematic uncertainties upon comparisons with theoretical predictions. However, the magnitudes of all of the above sensitivities are potentially less than those introduced when using a semi ideal growth factor analogue for certain conditions.



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