Melt blown nanofibers: Fiber diameter distributions and onset of fiber breakup

The aim of this study is to evaluate the susceptibility of landslides at Klang valley area, Malaysia, using a Geographic Information System (GIS) and remote sensing. Landslide locations were identified in the study area from interpretation of aerial photographs and from field surveys. Topographical and geological data and satellite images were collected, processed, and constructed into a spatial database using GIS and image processing. A data derived model (frequency ratio) and a knowledge-derived model (fuzzy operator) were combined for landslide susceptibility analysis. The nine factors that influence landslide occurrence were extracted from the database and the frequency ratio coefficient for each factor was computed. Using the factors and the identified landslide, the fuzzy membership values were calculated. Then fuzzy algebraic operators were applied to the fuzzy membership values for landslide susceptibility mapping. Finally, the produced map was verified by comparing with existing landslide locatio...

https://www.atlantis-press.com/article/1973.pdf

Application of an advanced fuzzy logic model for landslide susceptibility analysis

This work summarizes the current state of knowledge in the area of meltblown technology for production of polymeric nonwovens with specific attention to utilized polymers, die design, production of nanofibers, the effect of process variables (such as the throughput rate, melt rheology, melt temperature, die temperature, air temperature/velocity/pressure, die-to-collector distance, and speed) with relation to nonwoven characteristics as well as to typical flow instabilities such as whipping, die drool, fiber breakup, melt spraying, flies, generation of small isolated spherical particles, shots, jam, and generation of nonuniform fiber diameters.

/pdf/meltblown-technology-for-production-of-polymeric-microfibers-3tqri8wzvv.pdf

Meltblown technology for production of polymeric microfibers/nanofibers: A review

Polymeric fibrous constructs possess high surface area-to-volume ratios when compared with solid substrates and are quite commonly used as tissue engineering and cell growth scaffolds. An overview of important design and material considerations for fibrous scaffolds as well as an outline of both established and emerging solution- and melt-based fabrication techniques is provided. Innovative post-process surface modification avenues using “click” chemistry with both single and dual active cues as well as gradient cues, which maintain the fibrous structure are described. By combining process parameters with post-process surface modification, researchers have been able to selectively tune cellular response after seeding and culturing on fibrous constructs.

Processing and surface modification of polymer nanofibers for biological scaffolds: a review

This paper is a comprehensive review of the meltblown process and parameters. The meltblown process is complex because of the many parameters and interrelationships between those parameters. Due to the competitiveness of the industry, process settings and polymers used are secretive, but there are several key researchers that have published studies on the interactions of meltblown variables. A majority of the research conducted has been on the relationship of process parameters and mean fiber diameter in order to understand how to produce smaller and higher quality fibers. This paper offers suggestions for future research on specific meltblown parameters.

https://ojs.cnr.ncsu.edu/index.php/JTATM/article/download/342/275

Overview and Analysis of the Meltblown Process and Parameters

An air drawing model of a polymer in a melt blowing process is presented and solved by introducing the numerical computation results of the air jet flow field of the dual slot die. The model's prediction of fiber diameter tallies well with the experimental data. The effects of processing and die design parameters on fiber diameter are discussed. A lower polymer flow rate, higher initial polymer temperature, higher initial air velocity, higher initial air temperature, smaller angle between the slot and the spinneret axis, smaller width of the die head, and larger width of the slot can all yield finer fibers.

Modeling Polymer Air Drawing in the Melt Blowing Nonwoven Process

A polymer air-drawing model of Polybutylene Terephthalate (PBT) melt-blown nonwovens has been established. The predicted fiber diameter coincides with the experimental data. The effects of the processing parameters on the fiber diameter have been investigated. A lower polymer flow rate, a higher initial air velocity, and a larger die-to-collector distance can all produce finer fibers, whereas too high an initial air velocity and too large a die-to-collector distance contribute little to the polymer drawing of PBT melt-blown nonwovens. The results show the great potential of this research for the computer-assisted design of melt-blowing technology. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1750–1752, 2005

Fiber diameter of polybutylene terephthalate melt-blown nonwovens

The polymeric fluid flow in the feed distributor of melt blowing process is simulated using three-dimensional finite element method The numerical results are experimentally verified quantitatively and qualitatively using laser Doppler velocimetry and particle image velocimetry respectively The effects of the distributor's geometric parameters on the uniformity of the transverse flow distribution are investigated As the manifold angle increases, the flow distribution curve appears to transform gradually from a “hill” shape to a “bone” shape The uniformity of flow distribution at distributor outlet, especially the fluctuation at the central part, will be improved by increasing the land height © 2006 Wiley Periodicals, Inc J Appl Polym Sci 101: 1570–1574, 2006

Simulation of the polymeric fluid flow in the feed distributor of melt blowing process

The recognition and segmentation of pills in fabric images based on multi-scale matched filtering are introduced in this paper. According to the asymptotic intensity change of a pill, the pill was modeled using a Gaussian function. A matched filter is designed for detecting fabric pills. However, big pills and small pills may distribute randomly in an image and are hard to be detected simultaneously with the filter. To solve this problem, a group of matched filters, with variable-size convolution kernels using the multi-scale expansion and shrinkage properties of the wavelet function, are generated and convolved with the fabric image. Then pills, at each output of matched filtering, are recognized and we determined whether pills exist in the local area by merging all of the outputs of the multi-scale matched filtering. Finally, pills in the local area, where the existence of pills has been confirmed, are further segmented using an adaptive threshold method based on mean and weighted variance. The detection of pills on a real image shows that this method can satisfy the recognition and segmentation of different size pills and is helpful for quantitatively describing the pilling information.

Detecting Pills in Fabric Images Based on Multi-scale Matched Filtering

The statistical and artificial neural network (ANN) models are established for predicting the fiber diameter of spunbonded nonwovens from the processing parameters. The ANN of Bayesian frameworks produces smaller prediction errors and thus is determined to be the preferred network. Results show that the ANN model yields more accurate and stable prediction than the statistical model, and a reasonably good ANN model can be established with relatively few data points. Four methods are used to reveal the relative importance of the processing parameters in terms of their effect on the fiber diameter. It is found that the initial polymer temperature plays an most important role in reducing the fiber diameter, while the effect of the initial air temperature is not significant. Using an established ANN model, computer simulations of the effects of the processing parameter on the fiber diameter are carried out. It is found that higher polymer melt index, smaller polymer flow rate, higher initial polymer t...

Ting Chen

Papers

Modeling Polymer Air Drawing in the Melt Blowing Nonwoven Process

Fiber diameter of polybutylene terephthalate melt-blown nonwovens

Simulation of the polymeric fluid flow in the feed distributor of melt blowing process

Detecting Pills in Fabric Images Based on Multi-scale Matched Filtering

Simulating the drawing of spunbonding nonwoven process using an artificial neural network technique