Nanofibrous morphology of electrospun chitosan nanocomposites reinforced with WS2 nanotubes: A design-of-experiments study

2017 ◽  
Vol 48 (1) ◽  
pp. 119-145 ◽  
Author(s):  
Apostolos Baklavaridis ◽  
Ioannis Zuburtikudis ◽  
Costas Panayiotou
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Polymer Solution ◽  
Electric Field Strength ◽  
Response Surface ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Electron Microscopic ◽  
Inorganic Nanotubes ◽  
The Individual

Chitosan nanofibers reinforced with tungsten disulfide inorganic nanotubes (INT-WS2) were fabricated in this study. The aim was to investigate the effect of the material parameters and the electrospinning process parameters on the obtained nanofibrous morphology of the mats. The INT-WS2 content, the polymer solution concentration, the electric field strength, and the solution's flow rate were the investigated factors within the framework of response surface methodology. Scanning electron microscopic and image analysis were used for the dimensional characterization of the nanofibrous morphology and the estimation of three selected responses. Two responses were related to the quality of the nanofibrous morphology: the number surface density of the beads ( Nbead) and the average bead-to-fiber diameter ( Dbead/ Dfiber). The third response was indicative of the fiber thickness ( Dfiber). The developed models as well as the coupling and the individual effects of the four investigated factors are given. The results indicate that the electrospun nanofibrous morphology is mostly affected by the polymer solution concentration, the electric field strength and the INT-WS2 loading. Furthermore, the response-surface results reveal possible experimental pathways that may be followed in order to obtain specified nanofibrous chitosan/INT-WS2 morphologies.

Molecular Dynamics Study of Confined Fluid in Graphene Nanopores

2014 ◽  
Vol 1061-1062 ◽  
pp. 205-208
Author(s):  
Kun Li ◽  
Jing Jie Sha ◽  
Lei Liu ◽  
Gen Sheng Wu ◽  
Wei Si ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Ionic Currents ◽  
Md Simulations ◽  
Solution Concentration ◽  
Main Peak ◽  
Ion Distributions ◽  
Solvent Molecules

With the miniaturization of the NEMS/MEMS, the size effect becomes significant in the nanochannels/nanopores through which fluid flows as well as the interface effect. By all-atom molecular dynamics (MD) simulations, the ion transportation is investigated in nanopores as well as the physical properties at solid-liquid interface. To describe the anion and cation distributions of NaCl solution in vicinity of graphene nanopores, a new MD model was developed, taking thermal vibration of wall atoms, the structure of solvent molecules and ion sizes into consideration. The main peak locations of ion distributions stayed unchanged by changing the nanopore size, the solution concentration and the electric field strength. The ionic currents increased linearly with the diameter and the electric field strength, while it increased non-linearly with the solution concentration.

Preparation of Chitosan based Nanofibers: Optimization and Modeling

2016 ◽  
Vol 14 (1) ◽  
pp. 283-288 ◽  
Author(s):  
K. Thirugnanasambandham ◽  
V. Sivakumar
Keyword(s):  
Polymer Solution ◽  
Response Surface ◽  
Applied Voltage ◽  
Solution Concentration ◽  
Electrospinning Process ◽  
Interactive Effects ◽  
Optimum Process ◽  
Process Conditions ◽  
Good Correspondence ◽  
Nanofiber Diameter

AbstractThe main objective of the present study is to prepare a chitosan based nanofiber and model the electrospinning process using response surface methodology (RSM). The electrospinning parameters such as collector distance, polymer solution concentration and applied voltage were optimized by using three-variable-three-level Box–Behnken design (BBD). Based on RSM analysis, second order polynomial equation was formed and it indicated good correspondence between experimental and predicted values. 3D response surface plots were used to study the individual and interactive effects of process variables on chitosan based nanofiber diameter. The optimum process conditions for the minimum chitosan based nanofiber diameter (0.3 µm) were found to be collector distance of 12 cm, polymer solution concentration of 25% and applied voltage of 6 kV.

Residual Charges during Electrospinning Assist in Formation of Piezoelectricity in Poly(Vinylidene Fluoride-co-Trifluoroethylene) Nanofibers

2015 ◽  
Vol 37 ◽  
pp. 13-19 ◽  
Author(s):  
A Young Choi ◽  
Hyeon Jun Sim ◽  
Min Kyoon Shin ◽  
Seon Jeong Kim ◽  
Youn Tae Kim
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Vinylidene Fluoride ◽  
Near Field ◽  
Electrospun Nanofibers ◽  
Electrospinning Process ◽  
Local Electric Field ◽  
Output Measurement ◽  
Poly Vinylidene Fluoride

We confirm piezoelectric performance of bottom electrospun PVDF-TrFE mat is higher than that of top mat and report the mechanism of additional poling process of electrospun nanofibers by local electric field which is originating from residual charges in far-field electrospinning process. Piezoelectric output measurement of poly (vinylidene fluoride-co-trifluoroethylene) electrospun nanofibers was performed by push test and output signals of bottom and top were compared. The local electric field strength calculated by simulation was higher than reported electric field strength of near-field electrospinning (10 MV/m). It can be concluded that the piezoelectric outputs of electrospun nanofibers tend to be improved by residual charge density and electrospinning condition.

scholarly journals Optimum Shape Design of Metal-Enclosed 550 kV Disconnectors Based on Response Surface Method and Finite Element Analysis

2015 ◽  
Vol 5 (4) ◽  
pp. 818-824
Author(s):  
R. Gong ◽  
S. Wang ◽  
X. Luo ◽  
M. Danikas
Keyword(s):  
Finite Element ◽  
Optimal Design ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Response Surface ◽  
Optimum Shape ◽  
Shape Design ◽  
Optimal Result ◽  
Surface Method

In this paper, the optimum shape design of 550 kV disconnectors in Gas Insulated Switchgears (GIS) are firstly presented employing the Finite Element Method (FEM) for electric field analysis coupled with an optimal design method. For effective analysis, the FEM is conducted in transient quasistatic electric field, using a finite element FORTRAN code. The structure parameters of disconnectors that provide the required electric field strength are obtained by the Response Surface Method (RSM) and the optimal values are presented by the variation in maximal electric field strength. The RSM and optimal design methods are also conducted by FORTRAN codes. The optimal result reveals that a uniform electric field distribution is achieved in 550 kV disconnectors. Additionally, the optimal result of disconnectors is verified by the proposed disconnector undertaken power frequency withstanding voltage of 740 kV for 1 minute, lightening impulse of 1675 kV, and operating impulse of 1300 kV, respectively.

scholarly journals Cell Permeabilisation, Microstructure and Quality of Dehydrated Apple Slices Treated with Pulsed Electric Field During Blanching

2018 ◽  
Vol 4 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Om Prakash Chauhan ◽  
Shima Shayanfar ◽  
Stefan Topefl
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Pulsed Electric Field ◽  
Cell Permeabilization ◽  
Electron Microscopic ◽  
Drying Time ◽  
Apple Slices ◽  
Microscopic Studies

ABSTRACTEffect of pulsed electric field as a blanching pretreatment on cell permeabilization, microstructure and quality of dehydrated apple slices was studied. Apple slices were pulsed electric field pretreated (1.0, 1.5 and 2.0 kV/cm using 25 and 75 pulses) at a temperature of 60 and 80°C in water followed by dehydration at 60°C in a cabinet dryer. Cell disintegration index was found to increase significantly (p<0.05) with increase in the electric field strength, number of pulses and blanching temperature and thereby reducing the drying time. The dehydrated slices showed lower hardness and higher lightness (L*) values for the samples treated at higher electric field strength for longer durations. Scanning electron microscopic studies of samples revealed better retention of cellular integrity when pre-treated at a low level of PEF (1.0 kV/cm using 25 pulses) and blanched at low temperature (60°C). However, the samples treated to a level of 1.5 kV/cm and 75 pulses of PEF with subsequent blanching temperature 80°C was found to yield optimum cell permeabilization. The study suggests that PEF can be used as an effective blanching pretreatment for achieve good quality dehydrated apple slices in less drying time. 

Optical Measurement of the Electric Field Strength in a Gel Insulator

2016 ◽  
Vol 136 (10) ◽  
pp. 1420-1421
Author(s):  
Yusuke Tanaka ◽  
Yuji Nagaoka ◽  
Hyeon-Gu Jeon ◽  
Masaharu Fujii ◽  
Haruo Ihori
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Optical Measurement

Effect of external magnetic field on lane formation in driven pair-ion plasmas

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Swati Baruah ◽  
U. Sarma ◽  
R. Ganesh
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Coupling Parameter ◽  
Critical Parameters ◽  
Coulomb Coupling ◽  
Lane Formation ◽  
Parameter Values

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

scholarly journals Investigating the feasibility of cerebellar transcranial direct current stimulation to facilitate post-stroke overground gait performance in chronic stroke: a partial least-squares regression approach

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Dhaval Solanki ◽  
Zeynab Rezaee ◽  
Anirban Dutta ◽  
Uttama Lahiri
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Chronic Stroke ◽  
Least Squares Regression ◽  
Significance Level ◽  
Gait Performance ◽  
Wilcoxon Rank Sum Test ◽  
Gait Parameters ◽  
The Mean

Abstract Background Investigation of lobule-specific electric field effects of cerebellar transcranial direct current stimulation (ctDCS) on overground gait performance has not been performed, so this study aimed to investigate the feasibility of two lobule-specific bilateral ctDCS montages to facilitate overground walking in chronic stroke. Methods Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2 mA via 3.14 cm2 disc electrodes for 15 min targeting (a) dentate nuclei (also, anterior and posterior lobes), and (b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at a 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID). Results The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p = 0.0257) and '%Stance Time Unaffected Leg' (p = 0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis (R2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10 m/s), TUG (MCID: 8 s), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation. Trial registration: Being retrospectively registered.

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