scholarly journals Production and analysis of electrospun PA 6,6 and PVA nanofibrous surfaces for filtration

2021 ◽  
Vol 72 (05) ◽  
pp. 552-560
Author(s):  
SEZEN DÖNMEZ DİNÇ ◽  
FATMA GÖKTEPE
Keyword(s):  
Composite Structures ◽  
Feeding Rate ◽  
Air Permeability ◽  
Filtration Efficiency ◽  
Unit Weight ◽  
Production Time ◽  
Pore Size Distributions ◽  
Average Fibre ◽  
Fibre Fineness ◽  
Different Levels

Electrospun nanofibrous surfaces were produced by using two different polymers (PA 6,6 and PVA) at three different levels of polymer feeding rate (0.2, 0.6 and 1.0 ml/h, respectively) and three different levels of production time in electrospinning (5, 10 and 15 minutes, respectively) and the effect of polymer type, polymer feeding rate and production time was determined by analyzing unit weight and thickness of the nanofibrous membranes as well as fibre fineness and pore size distributions. The results showed that much finer fibres were produced by PA 6,6 polymer compare to PVA. The minimum average fibre fineness was 150.96 nm (by PA 6,6 polymer; 0.2 ml/h; 5 min.) while maximum fibre fineness was 243.43 nm (by PVA polymer; 0.6 ml/h; 15 min.). Similarly, the pore sizes of nanofibrous surfaces produced by PA 6,6 were smaller compare to the ones produced by PVA polymer. The results also indicated that coarser fibres were produced as the polymer feed rate and electrospinning time increased. In the second part of the work, composite structures were obtained by combining nanofibrous surfaces with PP non-woven material and their air permeability and filtration efficiency by using an aerosol having 0.2–0.33 mm diameter range were analyzed. The air permeability of PA 6,6 nanofibrous surfaces were much higher compare to the ones produced by PVA and quite high filtration efficiency (99.901 %) was obtained with PA 6,6 nanofibrous surfaces. Also, potential of these nanofibrous surfaces was evaluated by analysing chemical groups eliminated following their exposure to cigarette smoke which was chosen as a specific case study.

scholarly journals Development of Needle-Punched Nonwoven Fabrics from Reclaimed Fibers for Air Filtration Applications

2014 ◽  
Vol 9 (1) ◽  
pp. 155892501400900 ◽  
Author(s):  
S. Sakthivel ◽  
Anban J.J. Ezhil ◽  
T. Ramachandran
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Air Permeability ◽  
Filtration Efficiency ◽  
Raw Material ◽  
Fine Tuning ◽  
Physical Parameters ◽  
Air Filtration ◽  
Nonwoven Fabrics

This paper reports an investigative study on the fabrication and measurement of the air permeability, mechanical properties, pore size distribution, and filtration efficiency of different nonwoven fabrics produced from reclaimed fibers by analytically changing the machine variables to manipulate the physical parameters of the nonwoven fabrics. Reclaimed fiber of cotton (60%) and polyester (40%) blend was used, so that the prospect of value addition to an inexpensive source of raw material could be explored. The changes in air permeability were interpreted in terms of fabric density profile and pore size distribution. The filtration parameters of filtration efficiency, dust holding capacity, and pressure drop were also calculated. Additionally, the effects of calendering on pore size and filtration properties were evaluated to discover the opportunity of fine-tuning and the performance of the filters. The outcome in this study reflected an overall development in all filtration characteristics due to the calendering operation.

scholarly journals On Transducers Localization in Damage Detection by Wave Propagation Method

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1937 ◽  
Author(s):  
Adam Stawiarski ◽  
Aleksander Muc
Keyword(s):  
Wave Propagation ◽  
Damage Detection ◽  
Composite Structures ◽  
Detection Efficiency ◽  
Detection System ◽  
Damage Index ◽  
Detection Methods ◽  
Levels Of Analysis ◽  
Wave Propagation Method ◽  
Different Levels

In this paper, the elastic wave propagation method was used in damage detection in thin structures. The effectiveness and accuracy of the system based on the wave propagation phenomenon depend on the number and localization of the sensors. The utilization of the piezoelectric (PZT) transducers makes possible to build a low-cost damage detection system that can be used in structural health monitoring (SHM) of the metallic and composite structures. The different number and localization of transducers were considered in the numerical and experimental analysis of the wave propagation phenomenon. The relation of the sensors configuration and the damage detection capability was demonstrated. The main assumptions and requirements of SHM systems of different levels were discussed with reference to the damage detection expectations. The importance of the damage detection system constituents (sensors number, localization, or damage index) in different levels of analysis was verified and discussed to emphasize that in many practical applications introducing complicated procedures and sophisticated data processing techniques does not lead to improving the damage detection efficiency. Finally, the necessity of the appropriate formulation of SHM system requirements and expectations was underlined to improve the effectiveness of the detection methods in particular levels of analysis and thus to improve the safety of the monitored structures.

scholarly journals The Influences of Loop Length and Raw Material on Bursting Strength Air Permeability and Physical Characteristics of Single Jersey Knitted Fabrics

2017 ◽  
Vol 12 (1) ◽  
pp. 155892501701200
Author(s):  
Züleyha Değirmenci ◽  
Ebru Çoruh
Keyword(s):  
Shape Factor ◽  
Strength Properties ◽  
Air Permeability ◽  
Raw Material ◽  
Unit Weight ◽  
Loop Length ◽  
Knitted Fabrics ◽  
Bursting Strength ◽  
Loop Shape ◽  
Single Jersey

This paper reports the effect of loop length and raw material on the air permeability and the bursting strength of plain knitted fabrics. In this study, a series of plain knitted fabrics were produced on a circular knitting machine with cotton, polyester, acrylic and viscose by Ne 30/1 yarns. Each fabric type was produced with four different stitch lengths. All the fabrics were knitted at the same machine setting in order to determine the effect of their structure on the fabric properties. Their geometrical and physical properties were experimentally investigated. The influences of the loop length and the raw material on the number of the courses per cm, number of the wales per cm, loop shape factor, thickness, fabric unit weight, tightness factor, air permeability and bursting strength are analyzed. Statistical analysis indicates that raw material and loop length significantly parameters affect the air permeability and the bursting strength properties of the fabrics.

scholarly journals Review of Structural Health Monitoring Methods Regarding a Multi-Sensor Approach for Damage Assessment of Metal and Composite Structures

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 826 ◽  
Author(s):  
Christoph Kralovec ◽  
Martin Schagerl
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Damage Assessment ◽  
Composite Structures ◽  
Joint Damage ◽  
Ultrasonic Waves ◽  
Physical Models ◽  
Monitoring Methods ◽  
Structural Health ◽  
Different Levels

Structural health monitoring (SHM) is the continuous on-board monitoring of a structure’s condition during operation by integrated systems of sensors. SHM is believed to have the potential to increase the safety of the structure while reducing its deadweight and downtime. Numerous SHM methods exist that allow the observation and assessment of different damages of different kinds of structures. Recently data fusion on different levels has been getting attention for joint damage evaluation by different SHM methods to achieve increased assessment accuracy and reliability. However, little attention is given to the question of which SHM methods are promising to combine. The current article addresses this issue by demonstrating the theoretical capabilities of a number of prominent SHM methods by comparing their fundamental physical models to the actual effects of damage on metal and composite structures. Furthermore, an overview of the state-of-the-art damage assessment concepts for different levels of SHM is given. As a result, dynamic SHM methods using ultrasonic waves and vibrations appear to be very powerful but suffer from their sensitivity to environmental influences. Combining such dynamic methods with static strain-based or conductivity-based methods and with additional sensors for environmental entities might yield a robust multi-sensor SHM approach. For demonstration, a potent system of sensors is defined and a possible joint data evaluation scheme for a multi-sensor SHM approach is presented.

Development of Methodological Support for the Study of Materials’ Air Permeability

2019 ◽  
Vol 945 ◽  
pp. 938-943
Author(s):  
I.A. Sheromova ◽  
A.S. Zheleznyakov
Keyword(s):  
Air Permeability ◽  
Control Procedure ◽  
Fibrous Materials ◽  
Additional Advantage ◽  
Textile Materials ◽  
The Subject ◽  
Properties Of Materials ◽  
Materials Used ◽  
Different Levels

The object of research of the article is the methodological and technical support for the process of studying the characteristics of ergonomic properties of materials used in the manufacture of garments, and the subject – the method for the determination of textile materials’ air permeability. The aim of the work is to simplify the method for determination of fibrous materials’ air permeability and to expand the technological capabilities of its instrument base while increasing the flexibility of the control procedure. To achieve this goal, the tasks related to the analysis of existing methods and technical means, and the development of a new method for determining the air permeability of textile materials were solved. The principal difference in the developed method is the possibility to conduct studies on the air permeability of textile materials at different levels of pressure drop on both sides of the sample, and not only in accordance with the standardized requirements. An additional advantage of the method is the possibility to create an online electronic database on the properties of materials. In comparison with analogues, the proposed method for the determination of air permeability ensures the accuracy and reliability of the data obtained, as well as facilitates the testing process by automation.

Improving Purification Filter Characteristics of Fine Dust Particles Based on Aramid 1313 Denier Technology

2014 ◽  
Vol 1073-1076 ◽  
pp. 854-859
Author(s):  
Jian Liang He ◽  
Heng Gen Shen ◽  
Jing Zhong Bi ◽  
Hong Jiang Xin
Keyword(s):  
Energy Conservation ◽  
Emission Reduction ◽  
Air Permeability ◽  
Filtration Efficiency ◽  
Filter Medium ◽  
Dust Particles ◽  
Fine Dust ◽  
Initial Resistance

In order to improve the effect of meta-aramid on filtering fine dust particles such as PM2.5, the fineness of the fine denier meta-aramid was discretized, and new differential fiber was obtained. According to the results, this filter medium was superior to conventional 2.2 dtex samples in terms of classified filtration and caused a more significant effect on collecting fine dust particles; the initial resistance remained unchanged roughly; and the air permeability could reach 279 L/(m2•s), demonstrating that this filter medium has a great advantage in filtration efficiency as well as energy conservation and emission reduction.

Characterization and Efficiency Evaluation of Regenerated Filter Media

2012 ◽  
Vol 727-728 ◽  
pp. 1643-1647
Author(s):  
Priscila Martins de Barros ◽  
Eduardo Hiromitsu Tanabe ◽  
Mônica Lopes Aguiar
Keyword(s):  
Electron Microscope ◽  
Cellulose Fiber ◽  
Air Permeability ◽  
Filtration Efficiency ◽  
Efficiency Evaluation ◽  
Aerodynamic Diameter ◽  
Filter Media ◽  
Removal Efficiencies ◽  
Phosphate Concentrate ◽  
Scanning Electron

This study aimed to evaluate the characteristics of virgin and regenerated filter media and their relation with filtration efficiencies for particles with aerodynamic diameter up to 20 µm. The permeability of the filter media was determined and their fibers were observed in a scanning electron microscope. Filtration efficiency was obtained from the dust cake formed. The particulate matter used was phosphate concentrate and the filter media were cellulose fiber filters. The results showed that regenerated filter media presented higher air permeability due to the opening of the fibers observed in the microphotographs obtained; lower removal efficiencies were observed for particles smaller than 2.5 µm; and for particles larger than 2.5 µm, the efficiencies were nearly the same as those of the virgin filter, which was approximately 100%. It was verified that the regenerated filter media lost their initial characteristics, but continued to be efficient for particles larger than 2.5 µm.

scholarly journals The Pore Size Distribution of Naturally Porous Cigarette Paper and its Relation to Permeability and Diffusion Capacity

2015 ◽  
Vol 26 (7) ◽  
Author(s):  
Bernhard Eitzinger ◽  
Maria Gleinser ◽  
Stefan Bachmann
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Filler Content ◽  
Air Permeability ◽  
Size Distributions ◽  
Diffusion Capacity ◽  
Pore Size Distributions ◽  
Cigarette Paper ◽  
And Diffusion

SummaryThe pore size distribution of cigarette paper determines its air permeability and diffusion capacity and thereby has a significant influence on the gas exchange of a cigarette through the cigarette paper during smoking and during smouldering. For the design of cigarettes and in particular of cigarette papers it is important to understand how the pore size distribution of the cigarette paper is affected by the paper composition and paper properties and how it influences air permeability and diffusion capacity.It was the aim of this study to investigate how the composition of the cigarette paper such as filler content, fibre type and burn additive content qualitatively influenced the pore size distribution and how the pore size distribution and, in particular, which pore size range is correlated with air permeability and diffusion capacity, respectively. To this end eight naturally porous cigarette papers were selected which differed in air permeability, diffusion capacity, fibre type, filler content and burn additive content. The pore size distributions of these papers were measured by mercury porosimetry before and after the papers had been heated to 230 °C for 30 min. The pore size distributions were investigated for qualitative differences when air permeability, fibre type and filler content of the cigarette paper are modified. Furthermore by appropriate weighting of the pore size distributions optimal correlations between a weighted pore volume and air permeability or diffusion capacity were determined. The results show a good correlation with correlation coefficients greater than 0.9 for air permeability as well as for diffusion capacity. The results indicate that large pores are better correlated with changes in air permeability, while small pores are more strongly correlated with changes in diffusion capacity and support previous theoretical results obtained from flow and diffusion models. They also demonstrate the tight relationship between pore size distribution, air permeability and diffusion capacity, which makes the pore size distribution a tool to further optimize cigarette papers, for example, with respect to carbon monoxide yields in the smoke of a cigarette. [Beitr. Tabakforsch. Int 26 (2015) 312-319]

Development of polyester needle-punched nonwoven fabrics for filter press applications

2018 ◽  
Vol 48 (10) ◽  
pp. 1566-1579 ◽  
Author(s):  
G Thilagavathi ◽  
N Muthukumar ◽  
S Neelakrishnan ◽  
R Santhosh Egappan
Keyword(s):  
Nonwoven Fabric ◽  
Filtration Efficiency ◽  
Filter Press ◽  
Woven Fabric ◽  
Nonwoven Fabrics ◽  
Fabric Filter ◽  
Cake Discharge ◽  
Fibre Fineness ◽  
Filtration Properties ◽  
Filter Fabrics

This paper reports the development of nonwoven fabric by needle-punching technique for filter press application in textile effluent treatment plant. For filter press development, the nonwoven fabric was reinforced with the nylon scrim as the central layer in order to withstand the filtration pressure. The nonwoven fabrics were developed using different denier polyester fibres and changing punch density. The influence of fibre fineness and punch density on the properties of nonwovens was investigated. The filtration parameters such as filtration efficiency, dewatering efficiency, blinding tendency and cake discharge properties of the developed nonwoven filter fabrics filter fabrics were evaluated and compared with existing woven fabric filter media. The influence of calendering on the filtration properties of the nonwovens was also studied. The results showed that bursting strength of the developed nonwovens increased with increase in fibre fineness and decrease in punch density. It was also found that the air permeability of the developed nonwovens varied inversely in relation to punch density and the proportion of fine fibres. It was observed that developed nonwovens had 8% higher filtration efficiency and 6% higher dewatering efficiency compared to the existing woven fabric filter media. The blinding resistance and cake discharge properties were slightly lower than that of woven fabric filter. It was found that calendering improves filtration properties of the developed nonwoven fabrics.

scholarly journals Windmill Palm Fiber/Polyvinyl Alcohol Nonwoven Fibrous Polymeric Materials

2016 ◽  
Vol 11 (4) ◽  
pp. 155892501601100 ◽  
Author(s):  
Changjie Chen ◽  
Guicui Chen ◽  
Guangxiang Sun ◽  
Jiayi Wang ◽  
Guohe Wang
Keyword(s):  
Polyvinyl Alcohol ◽  
Length Distribution ◽  
Polymeric Materials ◽  
Air Permeability ◽  
Filtration Efficiency ◽  
Acoustic Properties ◽  
Digital Microscopy ◽  
Absorption Properties ◽  
Palm Fiber ◽  
Nonwoven Materials

Three types of wet-laid nonwoven materials with windmill palm fibril (WPFL), WPFL /windmill palm fiber bundles (WPFB) and windmill palm fiber (WPF)/polyvinyl alcohol (PVA), were prepared. The morphology and length distribution of WPFL and WPFB were analyzed by digital microscopy and image processing software. The filtration efficiency, air permeability and sound absorption properties of 12 samples of wet-laid nonwoven materials were tested. Adding PVA improved the porosity and enhanced the filtration efficiency, air permeability and acoustic properties of the nonwovens.

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