scholarly journals The Effect of Temperature and Humidity on the Filtration Performance of Electret Melt-Blown Nonwovens

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4774
Author(s):  
Chao Liu ◽  
Zijian Dai ◽  
Bin He ◽  
Qin-Fei Ke
Keyword(s):  
Pressure Drop ◽  
Relative Humidity ◽  
Surface Potential ◽  
Filtration Efficiency ◽  
Treatment Temperature ◽  
Effect Of Temperature ◽  
Fiber Morphology ◽  
Adsorption Effect ◽  
Filtration Performance ◽  
Temperature And Humidity

Electret melt-blown nonwovens are widely used for air purification due to their low pressure drop and high filtration efficiency. However, the charge stability could be affected by the ambient temperature and humidity, reducing the filtration efficiency, resulting in the electret melt blown filter not providing effective protection. Herein, we used corona charge to prepare electret melt-blown nonwovens and systematically studied the effects of different temperature and humidity on the structure, morphology, filtration performance, and surface potential within 24 h. The effect of treatment temperature and humidity on pressure drop was minimal because the fiber morphology and web structure of melt-blown nonwovens were not damaged. When the treatment temperature was lower than 70 °C, the effect on the filtration efficiency of the sample was small, but when the temperature increased to 90 or 110 °C, the filtration efficiency decreased significantly with the increase of the treatment time, and the surface potential also declined similarly. In conclusion, high temperatures will lead to charge escape and reduce the electrostatic adsorption effect. Furthermore, at the same temperature, increasing relative humidity can accelerate the charge release and make the filtration efficiency drop more. After the sample was treated at 110 °C and 90% relative humidity for 24 h, the filtration efficiency decreased from 95.49% to 38.16% at a flow rate of 14.16 cm s−1, and the surface potential dropped to the lowest value of −1.01 kV. This result shows that all links of electret melt-blown filter material from raw material to final use should be avoided in high temperature and high humidity conditions to ensure the protection effect.

scholarly journals Effect of Temperature on the Structure and Filtration Performance of Polypropylene Melt-Blown Nonwovens

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Si Cheng ◽  
Alam S. M. Muhaiminul ◽  
Zhonghua Yue ◽  
Yan Wang ◽  
Yuanxiang Xiao ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Pore Size ◽  
Fiber Diameter ◽  
Temperature Treatment ◽  
Filtration Efficiency ◽  
Effect Of Temperature ◽  
Filtration Performance ◽  
Different Temperatures ◽  
Polypropylene Melt ◽  
Filtration Properties

AbstractBy applying the simultaneous corona-temperature treatment, the effect of electret temperature on the structure and filtration properties of melt-blown nonwovens was investigated. Fiber diameter, pore size, thickness, areal weight, porosity, crystallinity, filtration efficiency, and pressure drop were evaluated. The results demonstrated that some changes occurred in the structure of electret fabrics after treatment under different temperatures. In the range of 20°C~105°C, the filtration efficiency of melt-blown nonwovens has a relationship with the change in crystallinity, and the pressure drop increased because of the change in areal weight and porosity. This work may provide a reference for further improving filtration efficiency of melt-blown nonwovens.

scholarly journals Self-Supporting Three-dimensional Electrospun Nanofibrous Membrane for Highly Efficient Air Filtration

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2567
Author(s):  
Gaofeng Zheng ◽  
Zungui Shao ◽  
Junyu Chen ◽  
Jiaxin Jiang ◽  
Ping Zhu ◽  
...  
Keyword(s):  
Pressure Drop ◽  
High Performance ◽  
Three Dimensional ◽  
Filtration Efficiency ◽  
Nanofibrous Membrane ◽  
Air Filtration ◽  
Fiber Morphology ◽  
Filtration Performance ◽  
Fibrous Filters ◽  
New Strategy

High-performance air filtration was the key to health protection from biological and ultrafine dust pollution. A self-supporting, three-dimensional (3D) nanofibrous membrane with curled pattern was electrospun for the filtration, of which the micro-fluffy structure displayed high-filtration efficiency and low-pressure drop. The flow field in the 3D filtration membrane was simulated to optimize the process parameters to increase the filtration performance. The qualification factor increased from 0.0274 Pa−1 to 0.0309 Pa−1 by 12.77% after the optimization of the electrospinning parameters. The best filtration efficiency and pressure drop were 93.6% and 89.0 Pa, separately. This work provides a new strategy to fabricate 3D structures through the construction of fiber morphology and promotes further improvement of air filtration performance of fibrous filters.

scholarly journals The Effect of Temperature and Humidity May Reduce the Growth Rate of the Coronavirus Disease 2019 Epidemic

2020 ◽  
Author(s):  
Lei Qin ◽  
Qiang Sun ◽  
Jiani Shao ◽  
Yang Chen ◽  
Xiaomei Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Relative Humidity ◽  
Effect Of Temperature ◽  
Average Temperature ◽  
Temperature And Humidity ◽  
Scatter Plots ◽  
Low Humidity ◽  
Average Relative Humidity ◽  
Effects Of Temperature ◽  
The Relationship

Abstract Background: The effects of temperature and humidity on the epidemic growth of coronavirus disease 2019 (COVID-19)remains unclear.Methods: Daily scatter plots between the epidemic growth rate (GR) and average temperature (AT) or average relative humidity (ARH) were presented with curve fitting through the “loess” method. The heterogeneity across days and provinces were calculated to assess the necessity of using a longitudinal model. Fixed effect models with polynomial terms were developed to quantify the relationship between variations in the GR and AT or ARH.Results: An increased AT dramatically reduced the GR when the AT was lower than −5°C, the GR was moderately reduced when the AT ranged from −5°C to 15°C, and the GR increased when the AT exceeded 15°C. An increasedARH increased theGR when the ARH was lower than 72% and reduced theGR when the ARH exceeded 72%.Conclusions: High temperatures and low humidity may reduce the GR of the COVID-19 epidemic. The temperature and humidity curves were not linearly associated with the COVID-19 GR.

The Effect of a Difference in Temperature and Humidity on certain Reactions of Female Aëdes aegypti (L.)

1952 ◽  
Vol 43 (1) ◽  
pp. 221-229 ◽  
Author(s):  
Alec H. Parker
Keyword(s):  
Relative Humidity ◽  
Aedes Aegypti ◽  
Room Temperature ◽  
Climatic Conditions ◽  
Effect Of Temperature ◽  
Full Description ◽  
Temperature And Humidity ◽  
Conditioning Effect ◽  
The Difference ◽  
C 50

Sir Rickard Christophers (1947) working at 25°C. and a relative humidity of 80–90 per cent. found female Aëdes aegypti to be attracted by a warm dry surface at 40°C., and to be unaffected by a moist surface at room temperature. The writer (1948), working at 28°C. and 50–70 per cent. R.H. (usually near 50 per cent.) found the opposite: a warm dry surface at temperatures from 36°C. to 40°C. had no effect, while a moist surface at room temperature exerted a quite definite attraction. The purpose of the present experiments was to test the hypothesis that the difference between the results obtained in these two investigations was due to the difference in the ambient temperature and humidity.Repetition of the relevant experiments at 25°C, 85–90 per cent. R.H., and 28°C, 50–55 per cent. R.H., gave results indicating that temperature and humidity difference operating at the time of the experiment could account for part but not all of the discrepancy. There are indications that the remainder may have been a result of the conditioning effect of temperature and humidity differences operating on the insect prior to the experiment.The results emphasise the need for a full description of the climatic conditions under which behaviour work of the type discussed is performed.

scholarly journals Beware That COVID-19 Would Be Worse in Winter: A Study of a Global Panel of 1236 Regions

2020 ◽  
Author(s):  
Chen Zhang ◽  
Hua Liao ◽  
Eric Strol ◽  
Hui Li ◽  
Ru Li ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Large Scale ◽  
Government Intervention ◽  
Public Awareness ◽  
Weather Conditions ◽  
Transmission Risk ◽  
Effect Of Temperature ◽  
Analysis Model ◽  
The World ◽  
Temperature And Humidity

It is believe that weather conditions such as temperature and humidity have effects on COVID-19 transmission. However, these effects are not clear due to the limited observations and difficulties in separating impacts of social distancing. COVID-19 data and social-economic features of 1236 regions in the world (1112 re-gions at the provincial level and 124 countries with small land area) were collected. A Large-scale satellite data was combined with these data with a regression analysis model to explore effects of temperature and relative humidity on COVID-19 spreading, as well as the possible transmission risk by seasonal cycles. The result show that temper-ature and relative humidity are shown to be negatively correlated with COVID-19 transmission throughout the world. Further, the effect of temperature and humidity is almost linear based on our samples, with uncertainty sur-rounding any nonlinear effects. Government intervention (e.g. lockdown policies) and lower population movement contributed to the decrease the new daily case ratio. The conclusions withstand several robustness checks, such as observation scales and maximum/minimum temperature. Weather conditions are not the decisive factor in COVID-19 transmission, in that government intervention as well as public awareness, could contribute to the miti-gation of the spreading of the virus. As temperature drops in winter, the transmission possibly speeds up again. It deserves a dynamic government policy to mitigate COVID-19 transmission in winter.

Tunable Fabrication of Electrospun Polyvinyl Alcohol Nanofibrous Membrances for Effective Air Filtration

2017 ◽  
Vol 748 ◽  
pp. 423-427
Author(s):  
Jin Yu Zhao ◽  
Zhao Lin Liu ◽  
Ju Chuan Shan
Keyword(s):  
Pressure Drop ◽  
Polyvinyl Alcohol ◽  
Applied Voltage ◽  
Feed Rate ◽  
Low Pressure ◽  
Solution Concentration ◽  
Filtration Efficiency ◽  
Air Filtration ◽  
Filtration Performance

Polyvinyl alcohol (PVA) nanofibrous membrances for effective air filtration were fabricated by electrospinning. Tunable fiber morphologies can be formed by facilely regulating the solution concentration and the applied voltage, and their effect on filtration performance of the PVA membrances were also investigeted. Results show that the PVA membrance exhibits high filtration efficiency of 97.1% and low pressure drop of 113 Pa when the PVA concentration is 8 wt% and the applied voltage is 15 kV with a tip-to-collector distance of 15 cm and a feed rate of 1 ml/h.

scholarly journals Experimental study on filtration effect of oilfield sewage based on new polyurethane modified materials

2020 ◽  
Vol 82 (10) ◽  
pp. 2039-2050
Author(s):  
Bingcheng Liu ◽  
Hongsong Li ◽  
Ning Liu ◽  
Wenguang Jia
Keyword(s):  
Filter Material ◽  
Filtration Efficiency ◽  
Practical Significance ◽  
Micro Computed Tomography ◽  
Adsorption Effect ◽  
Filtration Performance ◽  
Quality Of Water ◽  
Solids Concentration ◽  
Computed Tomography Scanning ◽  
The Difference

Abstract In the process of oilfield wastewater treatment, the polymer-modified materials with special wettability have been recognized by many scholars for their high filtration efficiency and good adsorption effect. In this paper, we used micro-computed tomography scanning and infrared scanning technology to further explore the internal structure and surface chemistry of polyurethane modified materials and then established an experimental platform for the filtration performance of polyurethane modified materials. The change of suspended solids concentration and oil content in the sewage was tested under different filtration rate, filter layer thickness, and water quality. The results showed that the porosity of the filter material and the oil-absorbing material was 65.85% and 56.03% respectively, and the difference in the number of oxygen-containing functional groups on the surface of these two materials indicated different adsorption force for sewage impurities. And the polyurethane modified materials had good filtration performance. Through these experiments, we demonstrated that the quality of water filtrated by the polyurethane modified materials met the requirements of the ‘National Comprehensive Wastewater Discharge Standards’, and the filtration efficiency for suspended particles and oils in oily sewage was higher than 80%. These materials have important practical significance for the harmless treatment of oily sewage.

Study on Filtration Performance of Cylinder Metal Rubber Filtering Material

2009 ◽  
Vol 79-82 ◽  
pp. 75-78
Author(s):  
Ya Dong Guo ◽  
Hui Yan ◽  
Yu Hong Xia ◽  
Hong Yuan Jiang
Keyword(s):  
Pressure Drop ◽  
Small Diameter ◽  
Initial Pressure ◽  
Filtration Efficiency ◽  
Material Research ◽  
Filtration Performance ◽  
Metal Rubber ◽  
Filtration Material ◽  
Liquid Condition ◽  
Drop Flow

As a novel porous functional material, metal rubber (MR) had many advantages of high loading capacity, high anti-blocked capacity and adjustable porosity with outside pressure made the MR more suitable as filtration material. However, there was no related study and successful application nowadays except in Russia. This study detailed investigated the filtration performance of MR including the influence of wire line diameter, porosity and molding thickness on initial pressure drop under clean liquid condition and their effects on pressure drop-flow rate property and filtration efficiency under contaminated liquid condition. The results indicate that the initial pressure drop increased with the decrease of porosity and wire line diameter, however decreased with the decrease of molding thickness when the flow was constant. Filtration drop increased significantly with the decrease of porosity. MR material made of small diameter wires showed a high filtration efficiency and large pressure drop because of its’ fine micro-pore. Filtration drop rose with the increase of molding thickness however, the filtration efficiency was little affected. These results provide a suitable guideline for further MR filter appliance and MR material research.

Effect of Temperature, Relative Humidity and ACH on the Emission of Volatile Organic Compounds from Particleboard

2010 ◽  
Vol 113-116 ◽  
pp. 1874-1877 ◽  
Author(s):  
Yu Liu ◽  
Jun Shen ◽  
Xiao Dong Zhu
Keyword(s):  
Volatile Organic Compounds ◽  
Relative Humidity ◽  
Organic Compounds ◽  
Effect Of Temperature ◽  
Change Rate ◽  
Factors Influencing ◽  
Air Change Rate ◽  
Volatile Organic ◽  
Temperature And Humidity ◽  
Significant Factors

Particleboard has been indicated as one possible source of volatile organic compounds (VOCs) at normal indoor. This paper examines the VOCs emissions from the larch particleboards. Temperature, relative humidity and air change rate are significant factors influencing the VOCs emissions from particleboards. With the temperature and humidity various in the ranges from 23°C-40°C and 10%-70%RH the TVOC concentrations increased. Whereas the increasing of air change rate causes the TVOC concentration decreased.

Effect of Temperature and Humidity on Measuring Ionization Current Inside Contaminated Pipes

2013 ◽  
Author(s):  
Pingchuan Li ◽  
Xianguo Tuo ◽  
Mingzhe Liu ◽  
Jun Ren ◽  
Qibiao Wang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Long Range ◽  
Regression Method ◽  
Experimental Results ◽  
Ion Current ◽  
Effect Of Temperature ◽  
Multiple Regression Method ◽  
Temperature And Humidity ◽  
Different Temperatures ◽  
Effects Of Temperature

This paper reported the experimental results of ion current under different temperatures and relative humidity using long range alpha detector (LRAD). An approximation relation between the measuring values, temperatures and relative humidity has been obtained using the linear multiple regression method. The experimental results have shown that the measuring values decrease with the increase of temperature and humidity. The influence of humidity on results outweighs that of temperatures. And both temperature and humidity are obviously negative correlated with measured values. Further experiments will be performed to confirm the coupling effects of temperature and humidity and reported later.

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