The electrospinning process, conditions and control

Author(s):  
B. Robb ◽  
B. Lennox
Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Ming-Hung Shu ◽  
Dinh-Chien Dang ◽  
Thanh-Lam Nguyen ◽  
Bi-Min Hsu ◽  
Ngoc-Son Phan

For sequentially monitoring and controlling average and variability of an online manufacturing process, x¯ and s control charts are widely utilized tools, whose constructions require the data to be real (precise) numbers. However, many quality characteristics in practice, such as surface roughness of optical lenses, have been long recorded as fuzzy data, in which the traditional x¯ and s charts have manifested some inaccessibility. Therefore, for well accommodating this fuzzy-data domain, this paper integrates fuzzy set theories to establish the fuzzy charts under a general variable-sample-size condition. First, the resolution-identity principle is exerted to erect the sample-statistics’ and control-limits’ fuzzy numbers (SSFNs and CLFNs), where the sample fuzzy data are unified and aggregated through statistical and nonlinear-programming manipulations. Then, the fuzzy-number ranking approach based on left and right integral index is brought to differentiate magnitude of fuzzy numbers and compare SSFNs and CLFNs pairwise. Thirdly, the fuzzy-logic alike reasoning is enacted to categorize process conditions with intermittent classifications between in control and out of control. Finally, a realistic example to control surface roughness on the turning process in producing optical lenses is illustrated to demonstrate their data-adaptability and human-acceptance of those integrated methodologies under fuzzy-data environments.


Author(s):  
Eduard Krylov

Integrative bilingual teaching/learning of foreign language and engineering disciplines at a technical university provides a good opportunity for students of the personal growth both in cognitive and communicative aspects, which contributes to their better positions in the labor market. To put this opportunity into practice, the educators should have clear ideas about the goal of this educational process, psychological aspects accompanying the process, conditions of its implementation, basic units of teaching/learning, means of monitoring, assessment, and control and some others. All these components of methodology are discussed in this chapter.


2013 ◽  
Vol 753-755 ◽  
pp. 230-235
Author(s):  
Yin Lan ◽  
Yan Feng Wang ◽  
Zhi Zheng Yang ◽  
Jiang Ping Rao ◽  
Xia Hong

This paper is considering the surface quality control of hot-rolled coil. Through analyzing patterns, distributing-regularities and components of surface defect of low-carbon coil of WISCO, got the conclusion that mould powder entrapment was the key factor that lead the defect’s occurrence. Based on discussing the mechanism of powder entrapment in mould, developed a type of high viscosity powder, optimized flow field of mould through modifying the structure of SEN, and improved other relevant process conditions, the incidence rate of this type of defect was under controlled effectively and the degradation rate of the coil caused by the defect dropped from about 4 percent to less than 0.2 percent at the end.


2018 ◽  
Vol 44 ◽  
pp. 00165 ◽  
Author(s):  
Karolina Sobczyk ◽  
Karol Leluk

Poly(lactic acid) electrospinning tests were carried out under various process conditions. Openwork structures with a high surface area to weight ratio have been obtained. Changing the parameters of the PLA electrospinning process resulted in products with different fiber morphology.


Author(s):  
Yunshen Cai ◽  
Michael Gevelber

Electrospinning produces submicron fibers for a variety of applications using a wide range of polymers. Achieving the desired fiber diameter, maximizing productivity, and minimizing variation are important production objectives. This paper addresses several important areas needed to develop a general electrospinning control approach including: developing a correlation between measurements, process conditions, and the resulting fiber diameter, developing a method to determine an operating regime that meets manufacturing objectives, and identifying process dynamics for controller design.


2010 ◽  
Vol 129-131 ◽  
pp. 365-369 ◽  
Author(s):  
Cheng Kun Liu ◽  
Mei Yu Chen ◽  
Run Jun Sun ◽  
Wei Hua Zhang ◽  
Zhao Huan Zhang ◽  
...  

In electrospinning, outlook of fibrous assembly changes not only with the variation of collecting setups, but with the electrospinning process. For example, formation of multiple jets on a single droplet at special electrospinning conditions can produce several regions of fibrous webs simultaneously, which is bound to bring a great increase of production of nanofibers. The initiation method of multiple jets during electrospinning was derived through an experimental investigation by means of a high-speed camera, which was used to obtain the information of the shape change of a droplet along with process conditions, such as solution concentration, voltage and flow rate. Results showed that multiple jets could be initiated in a controlled manner when droplets experienced several cycles of dripping at relatively high voltages and flow rates in a certain concentration range. An interesting phenomenon of the auto-initiation of double jets was further observed in our experiment.


Author(s):  
Xuri Yan ◽  
Michael Gevelber

In many emerging, high value electrospinning applications, the diameter distribution of electrospun fibers has important implications for the product’s performance and process reproducibility. However, the current state-of-the-art electrospinning process results in diameter distribution variations, both during a run and run-to-run. To address these problems, a vision-based, open loop system has been developed to better understand the process dynamics. The effects of process parameters on fiber diameter distributions are investigated, process dynamics are identified, and the relation between measurable variables and the resulting fiber diameter distribution is analyzed.


2019 ◽  
Vol 13 (2) ◽  
pp. 195-216 ◽  
Author(s):  
D. C. Gernat ◽  
E. Brouwer ◽  
M. Ottens

AbstractAlthough present in concentrations in microgrammes per litre level, aldehydes, in particular those derived from Strecker degradation, are known to majorly contribute to the undesired wort flavour of alcohol-free beers. In order to improve currently available products, one needs to understand the underlying cause for the over-prevalence and identify leverage points and methods to selectively reduce the aldehydes in alcohol-free beers. This work gives a short overview on relevant flavour-active wort flavours identified in alcohol-free beer and on their involved chemical formation pathways. Consequently, aldehyde removal technologies in general and in brewing industry are presented. Adsorptive removal of off-flavours by aldehyde-scavenging groups is already widely exploited in the packaging industry and may achieve reduction of these components to near depletion, depending on the process conditions. Its principles are adaptable to recovering off-flavours before filling. Also, supercritical CO2 extraction has been successfully applied to separate flavours from food matrices. In brewing, the focus has been set to biologic conversion by restricted fermentation steps, but the reduction of key components of more than 70% is not achieved. Newer developments focus on thermal separation techniques that not only include non-specific physical dealcoholisation but also more selective technologies such as pervaporation, where aldehydes are reduced to near depletion. However, for most unit operations, selectivity and capacity are not yet investigated. Future research should explore the shortcomings of current techniques and overcome bottlenecks either by developing more specific methods for aldehyde removal and/or a clever combination of unit operations to optimise the separation and process integration.


2001 ◽  
Vol 43 (7) ◽  
pp. 381-386
Author(s):  
E. I. Volcke ◽  
L. Clement ◽  
M. Van De Steene ◽  
P. A. Vanrolleghem

This paper gives an overview of the poster sessions on sensor/monitoring, control and decision support systems, as they have been presented during the Watermatex 2000 conference. The COST benchmark for the comparison of different control strategies has been analysed. Two different teams have performed research on the control of sewers to decrease combined sewer overflows. Extended methods for gauge monitoring accuracy are proposed. The use of adaptive controllers for improving control performance under varying process conditions is demonstrated in two applications. More advanced techniques for monitoring and control are also discussed. Applications are situated in the field of fault detection and control. Three posters on decision support systems have presented the methodology and architecture of specific applications. Rewarded posters are mentioned and have been selected for full paper publication in this issue of Wat. Sci. Tech.


2016 ◽  
Vol 14 (1) ◽  
pp. 283-288 ◽  
Author(s):  
K. Thirugnanasambandham ◽  
V. Sivakumar

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.


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