scholarly journals Quantitative Disorder Analysis and Particle Removal Efficiency of Polypropylene-Based Masks

MRS Advances ◽  
2020 ◽  
Vol 5 (56) ◽  
pp. 2853-2861
Author(s):  
R.A. Makin ◽  
K.R. York ◽  
A.S. Messecar ◽  
S.M. Durbin

AbstractWe demonstrate a methodology for predicting particle removal efficiency of polypropylene-based filters used in personal protective equipment, based on quantification of disorder in the context of methyl group orientation as structural motifs in conjunction with an Ising model. The corresponding Bragg-Williams order parameter is extracted through either Raman spectro-scopy or scanning electron microscopy. Temperature-dependent analysis verifies the presence of an order-disorder transition, and the methodology is applied to published data for multiple samples. The result is a method for predicting the particle removal efficiency of filters used in masks based on a material-level property.

2021 ◽  
Author(s):  
Swagatalaxmi Pujaru ◽  
Priyabrata Sadhukhan ◽  
Basudev Ghosh ◽  
Arup Dhara ◽  
Sachindranath Das

Abstract Lead free hybrid halide perovskite (CH3NH3)3Bi2Br9 has been successfully synthesized by mechano-chemical method. The microstructure analysis by Rietveld’s refinement method revealed that the crystal belongs to trigonal system with space group P3 ̅m1. The obtained microstructural parameters are well in agreement with the previously published data. Temperature-dependent ac conductivity, impedance spectroscopy, and complex dielectric properties have been investigated in detail. The negative temperature coefficient of resistance behaviour reveals the semiconducting nature of the materials. The complex impedance spectroscopy also supports the semiconducting nature of the sample with activation energy for conduction ~0.38 eV.


2012 ◽  
Vol 187 ◽  
pp. 269-272 ◽  
Author(s):  
Don Dussault ◽  
F. Fournel ◽  
V. Dragoi

Current work describes development, testing and verification of a single wafer megasonic cleaning method utilizing a transducer design that meets the extreme particle neutrality, Particle Removal Efficiency (PRE), and repeatability requirements of production scale wafer bonding and other applications requiring extremely low particle levels.


2017 ◽  
Vol 53 (No. 4) ◽  
pp. 226-231 ◽  
Author(s):  
Liu Junhe ◽  
Yan Yan ◽  
Yu Mingfu ◽  
Parajulee Megha N ◽  
Shi Peijian ◽  
...  

Temperature has a significant influence on development rates of insects and mites. Many parametric models were built to describe the temperature-dependent development rates. However, these models provided different shapes of the curves of development rate versus temperature. For different datasets, investigators have to spend much time on considering which the parametric model is the best for describing the temperature-dependent development rates. In the present study, we encourage investigators to use an important non-parametric model, the loess method, which belongs to local regression methods. The loesS method is used to fit some published data on the development rate of aphids to check the goodness-of-fit. We find that the loess method is very flexible for fitting the given datasets. Thus, we consider that the loess method can be used to describe the effect of temperature on the development rate of insects or mites.


2003 ◽  
Vol 788 ◽  
Author(s):  
Diana-Andra Borca-Tasciuc ◽  
Yann LeBon ◽  
Claire Nanot ◽  
Gang Chen ◽  
Theodorian Borca-Tasciuc ◽  
...  

ABSTRACTThis work reports temperature dependent thermal and electrical properties characterization of long (mm size) single-walled carbon nanotube strands. Electrical properties are measured using a 4-probe method. Thermal conductivity and specific heat capacity are determined using an AC driven, self-heating method. Normalized values of resistivity, thermal conductivity, specific heat, thermal diffusivity, and the temperature coefficient of resistance are reported. The trends observed in the temperature dependent properties are comparable with previously published data on multi-walled carbon nanotube strands measured with a similar technique.


2018 ◽  
Vol 50 (5) ◽  
pp. 665-672 ◽  
Author(s):  
Sarim Ahmed ◽  
Hassan Mohsin ◽  
Kamran Qureshi ◽  
Ajmal Shah ◽  
Waseem Siddique ◽  
...  

2019 ◽  
Vol 81 (3) ◽  
Author(s):  
Anita Kusuma Wardani ◽  
Ivan Ivan ◽  
Ivan Ruben Darmawan ◽  
Khoiruddin Khoiruddin ◽  
I Gede Wenten

The air quality in the world has been worsening in the last decades due to industrial, vehicle, cigarettes smoke, forest fire, and fuel usage. In this case, fine particles are the world’s greatest concern due to its aerodynamic properties which enable it to travel throughout the world. The current conventional technologies seem to have lost their reliability due to complexity, low removal efficiency, and high equipment cost. Membrane air filter brings new hope to answer this challenge. It gives high removal efficiency with an acceptable pressure drop to fulfill the need for clean air at a lower price. Recently, the introduction of nanofibre membrane as a low-cost membrane may broaden membrane application in air filtration. Compared to conventional membrane, nanofibre membrane offers some interesting features such as higher porosity, interconnected pore structure, and narrow pore size distribution that provide remarkable permeability. In this paper, the microporous polymeric membrane for air filtration especially for fine particles removal is reviewed including mechanism of fine particle removal, membrane preparation, and factor affecting filtration performance.


2009 ◽  
Vol 23 (12) ◽  
pp. 1709-1721 ◽  
Author(s):  
Francesca Barbagini ◽  
Sandip Halder ◽  
Tom Janssens ◽  
Karine Kenis ◽  
Kurt Wostyn ◽  
...  

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