scholarly journals Fractal-like multiple jets in electrospinning process

2020 ◽  
Vol 24 (4) ◽  
pp. 2499-2505
Author(s):  
Yu-Ke Wu ◽  
Yong Liu
Keyword(s):  
Surface Tension ◽  
Electrospinning Process ◽  
Taylor Cone ◽  
Solution Viscosity ◽  
Fiber Morphology ◽  
Factors Affecting ◽  
Multiple Jets ◽  
Spinning Process ◽  
Main Factors

The electrospinning process is greatly affected by the instability of Taylor cone, an instable point can eject a jet, and multiple instable points can produce multiple jets. A fractal-like multi-jet phenomenon was found in electrospinning process with auxiliary electrodes, and main factors affecting the spinning process were studied experimentally, which included solution viscosity, surface tension, and conductivity. The fractal-like multi-jet is feasible to control the fiber morphology and its output.

Electrospinning Process of Ethylene-co-Vinyl Alcohol Nanofiber with DMAC/IPA Solution System

2014 ◽  
Vol 1033-1034 ◽  
pp. 1036-1039 ◽  
Author(s):  
Yin Ling Zhang ◽  
Ting Ting Jiang ◽  
Xiu Li Cai ◽  
Wei Min Kang ◽  
Bo Wen Cheng
Keyword(s):  
Field Emission ◽  
Vinyl Alcohol ◽  
Electrospinning Process ◽  
Fiber Morphology ◽  
Solution System ◽  
Spinning Process ◽  
Electronic Microscope ◽  
Spun Fibers

The nanofibers of EVOH which was dissolved in DMAC/IPA solution system were successfully prepared by eletrospinning. Through designed the electrospinning parameter of EVOH and observed the fiber morphology by the Field Emission Scanning Electronic Microscope(FESEM), we analyzed the influence of different spinning parameters to the fibers. And finally the optimum spinning process of EVOH nanofibers was obtained, which has the spinning concentration of 18wt%, spinning voltage of 29kV and receiving distance of 18cm. The average diameters of the well spun fibers using the solution system were concentrated between 65nm-105nm.

Progress in the use of electrospun nanofiber electrodes for solid oxide fuel cells: a review

2020 ◽  
Vol 36 (8) ◽  
pp. 879-931
Author(s):  
Joseph Parbey ◽  
Qin Wang ◽  
Guangsen Yu ◽  
Xiaoqiang Zhang ◽  
Tingshuai Li ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Electrospinning Process ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Fiber Morphology ◽  
Factors Affecting ◽  
Structure And Property ◽  
Conducting Materials ◽  
Stability Issues

AbstractThe application of one-dimensional nanofibers in the fabrication of an electrode greatly improves the performance of solid oxide fuel cells (SOFCs) due to its advantages on electron transfer and mass transport. Various mixed ionic-electronic conducting materials with perovskites and Ruddlesden-Popper-type metal oxide structures are successfully electrospun into nanofibers in recent years mostly in solvent solution and some in melt forms, which are used as anode and cathode electrodes for SOFCs. This paper presents a comprehensive review of the structure, electrochemical performance, and development of anode and cathode nanofiber electrodes including processing, structure, and property characterization. The focuses are first on the precursor, applied voltage, and polymer in the material electrospinning process, the performance of the fiber, potential limitation and drawbacks, and factors affecting fiber morphology, and sintering temperature for impurity-free fibers. Information on relevant methodologies for cell fabrication and stability issues, polarization resistances, area specific resistance, conductivity, and power densities are summarized in the paper, and technology limitations, research challenges, and future trends are also discussed. The concluded information benefits improvement of the material properties and optimization of microstructure of the electrodes for SOFCs.

Bubble Electrospinning with an Auxiliary Electrode and an Auxiliary Air Flow

2020 ◽  
Vol 14 (1) ◽  
pp. 42-45 ◽  
Author(s):  
Xiao-Xia Li ◽  
Ji-Huan He
Keyword(s):  
Room Temperature ◽  
Air Flow ◽  
Positive Electrode ◽  
Auxiliary Electrode ◽  
Long Distance ◽  
Effective Technique ◽  
Factors Affecting ◽  
Multiple Jets ◽  
Spinning Process ◽  
Electric Field Force

Background: The patented bubble electrospinning, which is a simple and effective technique for mass-production of polymer nanofibers, has been studying extensively, but it is still under development. In the bubble electrospinning, multiple jets move from the positive electrode to the receptor, a long distance between the two electrodes is needed to guarantee complete solvent evaporation, as a result a relative high voltage is needed. Objective: The aim of the present study is to use an auxiliary electrode and an auxiliary air flow to improve bubble electrospinning with lower voltage and higher output than those by its traditional one. Methods: The modification of the bubble electrospinning with an auxiliary electrode and an auxiliary airflow is used to fabricate nanofibers. The auxiliary electrode is close to the positive electrode. The experiment was carried out at room temperature with 8%PVA solution. The result was analyzed with a S4800 cold field scanning electron microscope (SEM, Hitachi S-4800, Tokyo, Japan). Results: The auxiliary electrode can generate a strong induced electric field force. With the action of airflow, the jets will fly to the receptor instead of the auxiliary electrode. Conclusion: Both auxiliary electrode and auxiliary airflow are two important factors affecting the spinning process. It can reduce the spinning voltage and improve spinning efficiency.

Poly-L-lactide nanofibers by electrospinning – Influence of solution viscosity and electrical conductivity on fiber diameter and fiber morphology

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Jun Zeng ◽  
Hou Haoqing ◽  
Andreas Schaper ◽  
Joachim H. Wendorff ◽  
Andreas Greiner
Keyword(s):  
Electrical Conductivity ◽  
Molecular Weight ◽  
Surface Tension ◽  
Fiber Diameter ◽  
Solution Viscosity ◽  
Electrode Geometry ◽  
Fiber Morphology ◽  
Electrical Field ◽  
Bead Formation ◽  
Solution Increase

Abstract Poly-L-lactide (PLA) fibers were obtained by electrospinning of PLA / dichloromethane solutions. Formation of beaded fibers combined with decreased fiber diameters were observed for low PLA concentrations in solution. Increase of the electrical conductivity by addition of pyridinium formiate (PF) caused a significant reduction of bead formation. The electrospinning of dilute PLA / PF / dichloromethane solutions resulted in PLA nanofibers. Systematic variations clearly identified the solution viscosity and the electrical conductivity at otherwise fixed parameters (surface tension, molecular weight, electrode geometry, electrical field, etc.) as crucial parameters for the formation of beads upon electrospinning of PLA / dichloromethane solutions.

Influence of Electric Field Interference on Three Nozzles Electrospinning

2011 ◽  
Vol 189-193 ◽  
pp. 720-723 ◽  
Author(s):  
En Long Yang ◽  
Jing Jing Shi
Keyword(s):  
Electric Field ◽  
Equilateral Triangle ◽  
Electrospinning Process ◽  
High Yield ◽  
Fiber Morphology ◽  
Linear Arrangement ◽  
Electrical Field Strength ◽  
Multiple Jets ◽  
Industrial Use ◽  
Membrane Shape

The low production rate of electrospinning process may limit the industrial use of single needle system. To meet high yield requirement and uniform fibers, a bottom-up multiple jets electrospinning nozzle was designed. The influence of electric field interference on jet path, membrane shape and fiber morphology was investigated. Experiment finds that electrical field strength in the closer part of two nozzles is weakened due to electric field interference when the distance between two nozzles is close. Electric field, jet path, fiber web shape and fiber morphology of three nozzles electrospinning with linear arrangement, equilateral triangle arrangement and isosceles right triangle arrangement were also compared. Results show that electric field and spun fibers of three nozzles electrospinning with equilateral triangle arrangement is the most uniform.

Recent Rapid Climate Changes in Antarctic and their Influence on Low Diversity Ecosystems

2010 ◽  
Vol 17 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Katarzyna J. Chwedorzewska
Keyword(s):  
Environmental Variables ◽  
Climate Changes ◽  
Biological Significance ◽  
Global Changes ◽  
Factors Affecting ◽  
Low Diversity ◽  
Main Factors ◽  
The Antarctic ◽  
High Diversity ◽  
Temperature Water

ABSTRACTThe geographic position, astronomic factors (e.g. the Earth’s maximum distance from the Sun during winter), ice cover and altitude are the main factors affecting the climate of the Antarctic, which is the coldest place on Earth. Parts of Antarctica are facing the most rapid rates of anthropogenic climate change currently seen on the planet. Climate changes are occurring throughout Antarctica, affecting three major groups of environmental variables of considerable biological significance: temperature, water, UV-B radiation.Low diversity ecosystems are expected to be more vulnerable to global changes than high diversity ecosystems

Effect of Solution Properties and Operating Parameters on Needleless Electrospinning of Poly(Ethylene Oxide) Nanofibers Loaded with Bovine Serum Albumin

2019 ◽  
Vol 16 (10) ◽  
pp. 913-922 ◽  
Author(s):  
Ramprasath Ramakrishnan ◽  
Jolius Gimbun ◽  
Praveen Ramakrishnan ◽  
Balu Ranganathan ◽  
Samala Murali Mohan Reddy ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Salt Content ◽  
Electrospinning Process ◽  
Solution Viscosity ◽  
Operating Parameters ◽  
Solution Properties ◽  
Wire Electrode ◽  
Needleless Electrospinning

Background: This paper presents the effect of solution properties and operating parameters of polyethylene oxide (PEO) based nanofiber using a wire electrode-based needleless electrospinning. Methods: The feed solution was prepared using a PEO dissolved in water or a water-ethanol mixture. The PEO solution is blended with Bovine Serum Albumin protein (BSA) as a model drug to study the effect of the electrospinning process on the stability of the loaded protein. The polymer solution properties such as viscosity, surface tension, and conductivity were controlled by adjusting the solvent and salt content. The morphology and fiber size distribution of the nanofiber was analyzed using scanning electron microscopy. Results: The results show that the issue of a beaded nanofiber can be eliminated either by increasing the solution viscosity or by the addition of salt and ethanol to the PEO-water system. The addition of salt and solvent produced a high frequency of smaller fiber diameter ranging from 100 to 150 nm. The encapsulation of BSA in PEO nanofiber was characterized by three different spectroscopy techniques (i.e. circular dichroism, Fourier transform infrared, and fluorescence) and the results showed the BSA is well encapsulated in the PEO matrix with no changes in the protein structure. Conclusion: This work may serve as a useful guide for a drug delivery industry to process a nanofiber at a large and continuous scale with a blend of drugs in nanofiber using a wire electrode electrospinning.

Pitting Corrosion of Biomedical Titanium and Titanium Alloys: A Brief Review

2020 ◽  
Vol 16 ◽  
Author(s):  
Yu-Wei Cui ◽  
Liang-Yu Chen ◽  
Xin-Xin Liu
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Potential Temperature ◽  
Growth Stages ◽  
Factors Affecting ◽  
Ti Alloys ◽  
Pitting Corrosion Resistance ◽  
Superior Mechanical Properties ◽  
Good Biocompatibility ◽  
Main Factors

Abstract:: Thanks to their excellent corrosion resistance, superior mechanical properties and good biocompatibility, titanium (Ti) and Ti alloys are extensively applied in biomedical fields. Pitting corrosion is a critical consideration for the reliability of Ti and Ti alloys used in the human body. Therefore, this article focuses on the pitting corrosion of Ti and Ti alloys, which introduces the growth stages of pitting corrosion and its main influencing factors. Three stages, i.e. (1) breakdown of passive film, (1) metastable pitting, and (3) propagation of pitting, are roughly divided to introduce the pitting corrosion. As reviewed, corrosive environment, applied potential, temperature and alloy compositions are the main factors affecting the pitting corrosion of Ti and Ti alloys. Moreover, the pitting corrosion of different types Ti alloys are also reviewed to correlate the types of Ti alloys and the main factors of pitting corrosion. Roughly speaking, β-type Ti alloys have the best pitting corrosion resistance among the three types of Ti alloys.

scholarly journals Measuring the Efficiency of Football Clubs Using Data Envelopment Analysis: Empirical Evidence From Spanish Professional Football

SAGE Open ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 215824402198925
Author(s):  
Isidoro Guzmán-Raja ◽  
Manuela Guzmán-Raja
Keyword(s):  
Data Envelopment Analysis ◽  
High Efficiency ◽  
Sport Performance ◽  
Data Envelopment ◽  
Professional Football ◽  
Efficiency Measure ◽  
Factors Affecting ◽  
Football Clubs ◽  
Main Factors ◽  
Using Data

Professional football clubs have a special characteristic not shared by other types of companies: their sport performance (on the field) is important, in addition to their financial performance (off the field). The aim of this paper is to calculate an efficiency measure using a model that combines performance (sport and economic) based on data envelopment analysis (DEA). The main factors affecting teams’ efficiency levels are investigated using cluster analysis. For a sample of Spanish football clubs, the findings indicate that clubs achieved a relatively high efficiency level for the period studied, and that the oldest teams with the most assets had the highest efficiency scores. These results could help club managers to improve the performance of their teams.

scholarly journals Enzymatic Process for Cystoseira barbata Valorization: Ethanol Production and Additional By-Products

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 741
Author(s):  
Doinita-Roxana Cioroiu Tirpan ◽  
Ancaelena Eliza Sterpu ◽  
Claudia Irina Koncsag ◽  
Alina Georgiana Ciufu ◽  
Tănase Dobre
Keyword(s):  
Ethanol Production ◽  
Alcoholic Fermentation ◽  
Ethanol Yield ◽  
Product Yield ◽  
Liquid Ratio ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Cystoseira Barbata ◽  
Main Factors ◽  
Process Factors

The aim of this study is to evaluate the potential of dried Cystoseira barbata alga for ethanol production through alcoholic fermentation. The influence of the main factors affecting the fermentation are studied in the frame of a 23 factorial experimental plan. The main factors influencing the process are the fermentation temperature (t from 25 °C to 35 °C), the solid to liquid ratio (S/L from 0.040 g/g to 0.080 g/g), and the cellulase ratio (R from 8 U/g d.m to 16 U/g d.m.). The maximum volatile compounds yield of 0.2808 g/g d.m and ethanol yield of 0.0158 g/g d.m were favored by the following experimental conditions: process temperature of 35 °C, solid to liquid ratio of 0.0415, and enzyme ratio of 16 U/g d.m. A statistical model was used to correlate the product yield with the process factors. Additionally, 19 interesting bioactive compounds were found in the enzymatic hydrolysis and alcoholic fermentation broths which seem likely to maintain natural defence mechanisms against diseases and physical disorders.

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