scholarly journals Study of the Filtration Performance of Multilayer and Multiscale Fibrous Structures

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7147
Author(s):  
Vânia Pais ◽  
Carlos Mota ◽  
João Bessa ◽  
José Guilherme Dias ◽  
Fernando Cunha ◽  
...  
Keyword(s):  
Flow Rate ◽  
Unit Area ◽  
Polymer Concentration ◽  
Small Diameter ◽  
Filtration Efficiency ◽  
Potential Solution ◽  
Electrospinning Technique ◽  
Variation Of Parameters ◽  
Electrospun Nanofibres ◽  
Needle Diameter

As the incidence of small-diameter particles in the air has increased in recent decades, the development of efficient filtration systems is both urgent and necessary. Nanotechnology, more precisely, electrospun nanofibres, has been identified as a potential solution for this issue, since it allows for the production of membranes with high rates of fibres per unit area, increasing the probability of nanoparticle collision and consequent retention. In the present study, the electrospinning technique of polyamide nanofibre production was optimized with the variation of parameters such as polymer concentration, flow rate and needle diameter. The optimized polyamide nanofibres were combined with polypropylene and polyester microfibres to construct a multilayer and multiscale system with an increased filtration efficiency. We observed that the penetration value of the multilayer system with a PA membrane in the composition, produced for 20 min in the electrospinning, is 2.7 times smaller than the penetration value of the system with the absence of micro and nano fibers.

Effects of Processing Parameters on the Morphology and Size of Electrospun PHBV Micro- and Nano-Fibers

2007 ◽  
Vol 334-335 ◽  
pp. 1233-1236 ◽  
Author(s):  
Ho Wang Tong ◽  
Min Wang
Keyword(s):  
Tissue Engineering ◽  
Polymer Solution ◽  
Polymer Concentration ◽  
Solution Concentration ◽  
Processing Parameters ◽  
Electrospun Fibers ◽  
Effective Technique ◽  
Electrospinning Technique ◽  
Needle Diameter ◽  
Short Time

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to fabricate micro- and nano-fibrous, non-woven mats by electrospinning for potential tissue engineering applications. The morphology and size of electrospun fibers were assessed systematically by varying the processing parameters. It was found that the diameter of the fibers produced generally increased with electrospinning voltage, needle diameter for the polymer jet and polymer solution concentration. Beaded fibers were readily produced at low PHBV concentrations, whereas the needle was blocked within a very short time during electrospinning when the PHBV concentration was too high. At the polymer concentration of 7.5 % w/v, it was shown that beadless PHBV fibers could be generated continuously by adjusting the electrospinning parameters to appropriate values. This study has clearly demonstrated that electrospinning can be an effective technique to produce PHBV micro- and nano-fibers. It has also been shown that composite fibers containing hydroxyapatite (HA) can be produced using the electrospinning technique.

Rheological and Wall-Slip Behaviors of Polymer Based Drilling Foams

2015 ◽  
Author(s):  
Testi Sherif ◽  
Ramadan Ahmed ◽  
Subhash Shah ◽  
Mahmood Amani
Keyword(s):  
Flow Rate ◽  
Fluid Model ◽  
Polymer Concentration ◽  
Small Diameter ◽  
Wall Slip ◽  
Hydroxyethyl Cellulose ◽  
Flow Loop ◽  
Power Law Fluid ◽  
Foam Rheology ◽  
Newtonian Behavior

This paper present experimental study conducted on rheology of hydroxyethyl cellulose (polymer) based foams. The effects of foam quality, wall-slip, and polymer concentration on foam rheology have been experimentally investigated using a circulating flow loop. Foam quality and flow rate were varied from 50 to 80 percent and 1 to 52 L/min, respectively. To identify the existence of wall-slip, tests were performed using different diameter (13.4, 19.6 and 31.8 mm ID) pipe viscometers. Experimental results show expected trends; pressure loss increased with increasing flow rate and reduced with increasing pipe diameter. Slight wall-slip was observed in the small diameter viscometer. However, the measurements obtained from other viscometers do not indicate wall-slip. All tested foams exhibited strong non-Newtonian behavior, which increases with foam quality and polymer concentration. The rheology of foams best fits the power-law fluid model. Applying regression analysis, new correlations have been developed to predict rheology of polymer-based foams.

PVA-Ketoprofen Nanofibers Manufacturing Using Electrospinning Method for Dissolution Improvement of Ketoprofen

2013 ◽  
Vol 737 ◽  
pp. 166-175 ◽  
Author(s):  
Jessie S. Pamudji ◽  
Khairurrijal ◽  
Rachmat Mauludin ◽  
Titi Sudiati ◽  
Maria Evita
Keyword(s):  
Dissolution Rate ◽  
Solid Dispersion ◽  
Flow Rate ◽  
Polymer Concentration ◽  
Electrospinning Process ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Electrospinning Method ◽  
Rate Improvement

Background and purpose: Ketoprofen is an NSAIDs agent which has analgesic and anti inflammation effects. Ketoprofen is classified into class II in the biopharmaceutical classification system that has a high permeability but low solubility. Hence, the absorption rate of this substance is governed by its dissolution rate. Electrospinning is a method that combine solid dispersion technology and nanotechnology. This method can be selected to enhance the dissolution rate of active substances. The aim of this research is to improve the dissolution rate of ketoprofen through the preparation of polymeric nanofiber polivinyl alcohol (PVA) containing ketoprofen using electrospinning process. Methods: Preparation of nanofibers with various of PVA-ketoprofen ratio, flow rate, and PVA concentration in the solution were accomplished using electrospinning instrument. Casting solid dispersion film were also prepared by solvent evaporation method and used as a reference. The rates of dissolution of ketoprofen from each of nanofibers, casting films, and pure ketoprofen were conducted in HCl pH 1.2 medium at 37oC. Characterization of nanofibers was carried out using Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). Results: Nanofibers which contained of PVA-ketoprofen 1:1 in ratio w/w showed a significant improvement in dissolution (p<0.05) compared to the pure ketoprofen. Meanwhile, nanofibers obtained from a solution containing 7.5 % PVA (w/v) and 4 ml/h in flow rate showed the best dissolution rate improvement and significantly different (p<0.05) with either the casting film or the pure ketoprofen. The improvement of ketoprofen dissolution was due to the increasing of surface area of nanofiber and the change of ketoprofen from crystalline into amorphous form. Conclusion: Electrospinning technique can be used to improve the dissolution rate of ketoprofen through the PVA-ketoprofen nanofiber formation by choosing the appropriate polymer concentration and manufacturing process.

Absorption of oxygen into solutions of polymers

1986 ◽  
Vol 51 (10) ◽  
pp. 2127-2134 ◽  
Author(s):  
František Potůček ◽  
Jiří Stejskal
Keyword(s):  
Mass Transfer ◽  
Aqueous Solutions ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Liquid Flow ◽  
Flow Curve ◽  
Liquid Flow Rate ◽  
Polymer Concentration ◽  
Newtonian Liquids

Absorption of oxygen into water and aqueous solutions of poly(acrylamides) was studied in an absorber with a wetted sphere. The effects of changes in the liquid flow rate and the polymer concentration on the liquid side mass transfer coefficient were examined. The results are expressed by correlations between dimensionless criteria modified for non-Newtonian liquids whose flow curve can be described by the Ostwald-de Waele model.

scholarly journals The Enhancement of Pre-Storage Filtration Efficiency for the Rainwater Harvesting System in Malaysia

2018 ◽  
Vol 152 ◽  
pp. 02015
Author(s):  
Yoong Sion Ong ◽  
Ken Sim Ong ◽  
Y.k. Tan ◽  
Azadeh Ghadimi
Keyword(s):  
Stainless Steel ◽  
Flow Rate ◽  
Rainwater Harvesting ◽  
Filtration Efficiency ◽  
High Flow ◽  
High Flow Rate ◽  
Water Tank ◽  
Filtration System ◽  
Filter Screen ◽  
Water Piping

A conventional design of rainwater harvesting system collects and directs the rainwater through water piping from roof of building to the water storage. The filtration system which locates before the water tank storage and first flush bypass system is the main focus of the research. A filtration system consists of a control volume of filter compartment, filter screen (stainless steel mesh) and water piping that direct the water flow. The filtration efficiency of an existing filter “3P Volume Filter VF1” by industrial company is enhanced. A full scale filter design prototype with filter screen of 1000 μm stainless steel metal mesh is tested to compare with the original filter system design. Three types of water inlet setups are tested. Among the proposed water inlet setups, the 90° inlet setup with extension provides the best filtration rate per unit time, following by the 45° inlet setup. The 45° and 90° inlet setup has similar filtration efficiency at low to medium flow rate while 45° inlet setup has better efficiency at high flow rate. The filtration efficiency with the 90° inlet setup with extension is observed to maintain at highest value at medium to high flow rate. The overall filtration performance achieved by the 90° inlet setup with extension at low to high flow rate is between 34.1 to 35.7%.

Partial Admission, Axial Impulse Type Turbine Design and Partial Admission Radial Turbine Test for SCO2 Cycle

2017 ◽  
Author(s):  
Hyungki Shin ◽  
Junhyun Cho ◽  
Young-Jin Baik ◽  
Jongjae Cho ◽  
Chulwoo Roh ◽  
...  
Keyword(s):  
Axial Force ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Small Diameter ◽  
Volume Flow ◽  
Working Fluid ◽  
Rotating Speed ◽  
Turbo Generator ◽  
Partial Admission ◽  
Reduce Development Time

Power generation cycle — typically Brayton cycle — to use CO2 at supercritical state as working fluid have been researched many years because this cycle increase thermal efficiency of cycle and decrease turbomachinery size. But small turbomachinery make it difficult to develop proto type Supercritical Carbon dioxide (S-CO2) cycle equipment of lab scale size. KIER (Korea Institute of Energy Research) have been researched S-CO2 cycle since 2013. This paper is about 60kWe scale and sub-kWe class turbo generator development for applying to this S-CO2 cycle at the lab scale. A design concept of this turbo-generator is to use commercially available components so as to reduce development time and increase reliability. Major problem of SCO2 turbine is small volume flow rate and huge axial force. High density S-CO2 was referred as advantage of S-CO2 cycle because it make small turbomachinery possible. But this advantage was not valid in lab-scale cycles under 100kW because small amount volume flow rate means high rotating speed and too small diameter of turbine to manufacture it. Also, high inlet and outlet pressure make huge axial force. To solve these problem, KIER have attempt various turbines. In this paper, these attempts and results are presented and discussed.

Research on Deposition of Micro-Nano Aerosols in Rising Bubble Under Pool Scrubbing Condition

2018 ◽  
Author(s):  
Yanmin Zhou ◽  
Haifeng Gu ◽  
Qiunan Sun ◽  
Zhongning Sun ◽  
Jiqiang Su ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Bubbly Flow ◽  
Aerosol Deposition ◽  
Deposition Efficiency ◽  
Filtration Efficiency ◽  
Liquid Level ◽  
Gas Flow Rate ◽  
Reactor Accident ◽  
Rising Bubble

Aerosols as the main component of radioactive products in migration performance, which is an important factor that a unclear reactor accident present strong diffusion and affects the distributions of source and dose level in reactor containment, and they are therefore expected to be deposited in liquid phase such as in suspension pool and filtered containment venting device. In this paper, the deposition characteristics of micro-nano aerosols in rising bubble under pool scrubbing condition is studied with experiment, the aerosols size in the research range from 20 nm to 600 nm, and the bubble morphology mainly concern homogeneous bubbly flow. The results show that the deposition efficiency and mechanism of aerosol closely relate to gas flow rate, liquid level, particle size and bubbles size and so on. The aerosol deposition near 85nm is proved most difficult because of the convert of deposition mechanisms. In a high liquid level condition, micro-nano aerosol filtration efficiency is enhanced but gradually gradual. Under different gas flow rate, air bubble residence time and the bubble size distributions affect the filtration efficiency of aerosols.

scholarly journals Development and Characterization of pH-Dependent Cellulose Acetate Phthalate Nanofibers by Electrospinning Technique

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3202
Author(s):  
Gustavo Vidal-Romero ◽  
Virginia Rocha-Pérez ◽  
María L. Zambrano-Zaragoza ◽  
Alicia Del Real ◽  
Lizbeth Martínez-Acevedo ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
Polymer Concentration ◽  
Process Efficiency ◽  
Fickian Diffusion ◽  
Solvent Mixtures ◽  
Cellulose Acetate Phthalate ◽  
Scanning Calorimetry ◽  
Electrospinning Technique ◽  
Ph Dependent ◽  
Release Profiles

The aim of this work was to obtain pH-dependent nanofibers with an electrospinning technique as a novel controlled release system for the treatment of periodontal disease (PD). Cellulose acetate phthalate (CAP) was selected as a pH-sensitive and antimicrobial polymer. The NF was optimized according to polymeric dispersion variables, polymer, and drug concentration, and characterized considering morphology, diameter, entrapment efficiency (EE), process efficiency (PE), thermal properties, and release profiles. Two solvent mixtures were tested, and CHX-CAP-NF prepared with acetone/ethanol at 12% w/v of the polymer showed a diameter size of 934 nm, a uniform morphology with 42% of EE, and 55% of PE. Meanwhile, CHX-CAP-NF prepared with acetone/methanol at 11% w/v of polymer had a diameter of 257 nm, discontinuous nanofiber morphology with 32% of EE, and 40% of PE. EE and PE were dependent on the polymer concentration and the drug used in the formulation. Studies of differential scanning calorimetry (DSC) showed that the drug was dispersed in the NF matrix. The release profiles of CHX from CHX-CAP-NF followed Fickian diffusion dependent on time (t0.43−0.45), suggesting a diffusion–erosion process and a matrix behavior. The NF developed could be employed as a novel drug delivery system in PD.

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