scholarly journals An Adaptable Device for Scalable Electrospinning of Low- and High-Viscosity Solutions

Instruments ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 37
Author(s):  
McCarty ◽  
Giapis
Keyword(s):  
Relative Humidity ◽  
Liquid Film ◽  
Applied Voltage ◽  
Large Range ◽  
Research Question ◽  
Film Surface ◽  
High Viscosity ◽  
Device Performance ◽  
Rotating Drum ◽  
Viscous Solutions

This paper summarizes the design and construction of an adaptable electrospinner capable of spinning fluids over a large range of viscosities. The design accommodates needless electrospinning technologies and enables researchers to explore a large range of testing parameters. Modular parts can be exchanged for alternative versions that adapt to the research question at hand. A rotating drum electrode immersed halfway into a solution bath provides the liquid film surface from which electrospinning occurs. We tested and assessed several electrode designs and their electrospinning performance at higher (< 500 poise) viscosities. Relative humidity was found to affect the onset of electrospinning of highly viscous solutions. We demonstrate robust device performance at applied voltage up to 90 kV between the electrospinning electrode and the collector. Design and fabrication aspects are discussed in practical terms, with the intent of making this device reproducible in an academic student machine shop.

The dominant frequency analysis of interfacial wave in wet-gas pipeline transportation based on NIR absorption

2021 ◽  
pp. 1-10
Author(s):  
Zhiyue Zhao ◽  
Ning Zhao ◽  
Lide Fang ◽  
Xiaoting Li
Keyword(s):  
Liquid Film ◽  
Predictive Accuracy ◽  
Film Surface ◽  
Dominant Frequency ◽  
Wave Frequency ◽  
Interfacial Wave ◽  
Long Distance ◽  
Wet Gas ◽  
The Mean ◽  
Predictive Correlation

During the long-distance transportation of wet-gas, the dominant frequency is of great significance for the study of pipeline fatigue and damage, and the safety production. Therefore, the theoretical and experimental researches for dominant frequency are carried out increasingly. However, most of the current prediction correlation of dominant frequency are mainly applicable to atmospheric pressure conditions (0.1 MPa), and the prediction accuracy is not accurate enough. The paper obtains the time series signal of liquid film thickness by near-infrared (NIR) sensor, and then calculates the wave frequency by the power spectrum density (PSD). The performance of typical predictive correlation is evaluated and analyzed by utilizing the experimental data at different flow and pressure conditions (0.1–0.8) MPa. The structure of Strouhal number and Lockhart-Martinelli (L-M) parameter are optimized reasonably, the mean velocity of the liquid film surface, the density increment of gas core, the gas core mass flow and average liquid film velocity are considered in the L-M parameter, a modified interfacial wave frequency correlation is proposed. The results indicate that the mean absolute error of the predictive correlation is 9.06% (current data) and 25.64% (literature data). The new correlation has a better predictive accuracy.

Investigation of oxide layer on CdTe film surface and its effect on the device performance

2015 ◽  
Vol 40 ◽  
pp. 402-406 ◽  
Author(s):  
Han Jun-feng ◽  
Xiao Liu ◽  
Cha Li-mei ◽  
Jonathan Hamon ◽  
M.P. Besland
Keyword(s):  
Oxide Layer ◽  
Film Surface ◽  
Cdte Film ◽  
Device Performance

TiO2:Ce/CeO2 High Performance Insulators For Thin Film Electroluminescent Devices

1996 ◽  
Vol 424 ◽  
Author(s):  
A. R. Bally ◽  
K. Prasad ◽  
R. Sanjinés ◽  
P. E. Schmid ◽  
F. Lévy ◽  
...  
Keyword(s):  
High Performance ◽  
Large Range ◽  
Device Performance ◽  
Thermal Treatments ◽  
High Permittivity ◽  
Electroluminescent Devices ◽  
Device Efficiency ◽  
Notable Increase ◽  
Cerium Doping ◽  
Titanium Dioxide Thin Films

AbstractThe electrical properties of titanium dioxide thin films have been stabilised by cerium doping. These films have a high permittivity between 35 to 45 and withstand 650°C. Multilayer TiO2:Ce/CeO2 insulators have been fabricated. The breakdown voltage is increased by a factor 10 with a modest decrease in the permittivity (30 – 35 instead of 35 – 45).Electroluminescent devices (ELDs) with a classical ZnS:Mn phosphor have been prepared using TiO2:Ce as the first insulator and a TiO2:Ce/CeO2 multilayer as the second insulator. Compared with a standard ELD based on Y2O3 insulators, devices with the new insulators show a significant decrease of the threshold voltage along with a notable increase of the brightness. An important increase is also achieved in the total device efficiency which is maintained over a large range of brightness and transferred charge. Consequences of rapid thermal annealing and conventional thermal treatments on device performance have also been investigated.

scholarly journals Numerical Analysis of Laminar Convective Condensation with the Presence of Noncondensable Gas Flowing Downward in a Vertical Channel

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Mustapha Ait Hssain ◽  
Youness El Hammami ◽  
Rachid Mir ◽  
Sara Armou ◽  
Kaoutar Zine-Dine
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Relative Humidity ◽  
Liquid Film ◽  
Vertical Channel ◽  
Dimensionless Temperature ◽  
Condensation Process ◽  
Inlet Temperature ◽  
Mixture Flow ◽  
Noncondensable Gas

The purpose of this paper is to study and perform a numerical analysis of the simultaneous processes of mass and heat transfer during the condensation process of a steam in the existence of noncondensable gas (NCG) inside a descending vertical channel. In this study, the flow of the vapor-air mixture is laminar and the saturation conditions are prevailing at the inlet of the channel. The coupled control equations for liquid film, interfacial conditions, and mixture flow are solved together using the approach of finite volume. Detailed and valuable results are presented both in the liquid condensate film and in the mixing regions. These detailed results contain the dimensionless velocity and dimensionless temperature profiles in both phases, the dimensionless mass fraction of vapor, the axial variation of the dimensionless thickness of the film liquid δ⁎, and the accumulated condensate rate Mr as well the local Nusselt number Nuy. The relative humidity at the inlet varies from 60% to 100% and the inlet temperature from 40°C to 80°C. The results confirm that a decrease in the mass concentration of NCG by the increasing the inlet relative humidity has a direct influence on the liquid film layer, the local number of Nusselt, and the variation of condensation rate accumulated through the channel. The results also designate that an increase of the inlet relative humidity and the inlet temperature ameliorates the condensation process. The comparison made for the coefficient of heat transfer due to condensation process and the condensate liquid film thickness with the literature results is in good concordance which gives more credibility to our calculation model.

Deformation Characteristics of the Ultrathin Liquid Film Surface Considering the Effects of Polar Endgroups

2007 ◽  
Author(s):  
Shigehisa Fukui ◽  
Soichi Shimizu ◽  
Kiyomi Yamane ◽  
Hiroshige Matsuoka
Keyword(s):  
Liquid Film ◽  
Thin Liquid Film ◽  
Film Surface ◽  
Wave Theory ◽  
Initial Boundary ◽  
Surface Forces ◽  
Deformation Characteristics ◽  
Long Wave ◽  
Vdw Force ◽  
Time Evolution Equation

To examine deformations of ultra-thin but continuum liquid film, the long wave theory was employed. The long wave theory uses the time-evolution equation for the shape and deformation of the thin liquid film and includes the surface tensions and surface forces such as the van der Waals (vdW) force. By numerically solving the time-dependent long wave equation, deformations of the ultra-thin lubricant film considering the vdW pressure with initial/boundary configurations of the liquid surfaces were obtained.

scholarly journals A mobile form of the Henderson apparatus

1969 ◽  
Vol 67 (3) ◽  
pp. 437-448 ◽  
Author(s):  
H. A. Druett
Keyword(s):  
Relative Humidity ◽  
Rotating Drum ◽  
Mobile Form ◽  
Viral Aerosol

SUMMARYA modification of the Henderson apparatus is described which is mobile and which can produce bacterial or viral aerosol in air whose relative humidity can be chosen in the range 20–95 %. The apparatus forms a basic utility for microthread, rotating drum or other aerosol studies.Much help and advice has been given by Messrs. J. F. H. Peel and D. J. Garriock of the Engineering Section M.R.E. throughout the development of this apparatus. The proportioning valve is a modification of one originally used for a similar purpose by Mr K. R. May. Thanks are due to Messrs. G. J. Harper and A. M. Hood for criticism of the script.

Stability Analysis of Ultra-thin Liquid Film Surface : Influence of Boundary with Nanometer Spacing

2004 ◽  
Vol 2004.42 (0) ◽  
pp. 409-410
Author(s):  
Daigou AKASAKA ◽  
Kazuya YORINO ◽  
Hiroshige MATSUOKA ◽  
Shigehisa FUKUI
Keyword(s):  
Stability Analysis ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Film Surface

The Thermocapillary Convection in Locally Heated Laminar Liquid Film Flow Caused by a Co-Current Gas Flow in Narrow Channel

2003 ◽  
Author(s):  
E. Y. Gatapova ◽  
Y. V. Lyulin ◽  
I. V. Marchuk ◽  
O. A. Kabov ◽  
J.-C. Legros
Keyword(s):  
Free Surface ◽  
Analytical Solution ◽  
Liquid Film ◽  
Gas Flow ◽  
Surface Deformation ◽  
Plane Channel ◽  
Film Surface ◽  
Local Heat ◽  
Narrow Channel ◽  
Liquid Film Flow

A two-dimensional model of a steady laminar flow of liquid film and co-current gas flow in a plane channel is considered. It is supposed that the height of a channel is much less than its width. There is a local heat source on the bottom wall of the channel. An analytical solution for the temperature distribution problem in locally heated liquid film is obtained, when the velocity profile is linear. An analytical solution of the linearized equation for thermocapillary film surface deformation is found. A liquid bump caused by the thermocapillary effect in the region where thermal boundary layer reaches the film surface is obtained. Damped oscillations of the free surface may exist before the bump. This is obtained according to the solution of the problem in an inclined channel. It depends on the forces balance in the film. The defining criterion is found for this effect. The oscillations of free surface do not exist for horizontally located channel.

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