Comparison of Capillary Flow Porometry (CFP) and Liquid Extrusion Porometry (LEP) Techniques for the Characterization of Porous and Face Mask Membranes

This work aims to study the characterization of several membrane filters by using capillary flow porometry (CFP) and liquid extrusion porometry (LEP) to obtain their pore size distributions (PSD) and mean pore diameters (davg). Three polymeric membranes of different materials namely, polyethylene (PET), cellulose nitrate (CN), and FM (face mask), and one inorganic (namely, alumina Al2O3) from ultrafiltration (UF)/microfiltration (MF) and particle separation were analyzed using a pressure constant fluid/liquid extrusion porometer, developed at institute de la filtration et techniques séparatives (IFTS). Several porosimetric fluids have been used to wet and penetrate into the porous/fiber structure. The results show the accuracy of the setup on characterizing membranes in the UF/MF range by CFP, with reasonable agreement with nominal data of the filters. Additionally, LEP extension of the equipment obtained good agreement with nominal data and the CFP results, while filters presenting a microstructure of highly interconnected pores (face mask) resulted in clear differences in terms of resulting PSD and average sizes when CFP and LEP results are compared.

Influence of nonwoven fabric pore sizes on water vapor resistance

The influence of nonwoven fabric pores using the Brunauer–Emmet–Teller method, dry sieving and capillary flow porometry on water vapor resistance were investigated. For a better understanding of the nonwoven thickness impact on pores and water vapor resistance (and therefore the influence on comfort), two types of samples were investigated: nonwoven fabric bonded with the needling and nonwoven fabric additionally bonded with the calendering process. Water vapor resistance increased with increasing nonwoven fabric thickness, whereby it ranged from 11.33 to 15.62 m2 Pa W−1 for the non-calendered samples and it ranged from 5.19 to 9.85 m2 Pa W−1 for the calendered ones. Water vapor resistance showed a good linear correlation with the specific surface area, pore volume, apparent opening size and mean flow pore diameter.

Investigation of Coronal Leakage of Root Fillings after Smear Layer Removal with EDTA or Er,Cr:YSGG Laser through Capillary Flow Porometry

No studies have been performed evaluating the marginal seal of root fillings after direct exposure of root canal (RC) walls to Er,Cr:YSGG laser irradiation. Therefore, 75 root filled teeth (5 × 15–cold lateral condensation) were analyzed for through-and-through leakage (TTL) using capillary flow porometry (CFP). The cleaning protocol determined the experimental groups: (1) irrigation with NaOCl 2.5% and EDTA 17% or standard protocol (SP), (2) SP + Er,Cr:YSGG lasing (dried RC), (3) NaOCl 2.5% + Er,Cr:YSGG lasing (dried RC), (4) SP + Er,Cr:YSGG lasing (wet RC), and (5) NaOCl 2.5% + Er,Cr:YSGG lasing (wet RC). Groups 6 to 10 consisted of the same filled teeth with resected apices. Resection was performed after the first CFP measurement. CFP was used to assess minimum, mean flow, and maximum pore diameters after 48 h. Statistics were performed using nonparametric tests (P>0.05). Additional three roots per group were submitted to SEM of the RC walls. TTL was observed in all groups without statistically significant differences between the different groups for minimum, mean, and maximum pore diameter (P>0.05). In this study, the use of EDTA and/or Er,Cr:YSGG laser did not reduce through-and-through leakage in nonresected and resected roots.

A Novel Method for Measurement of Porosity in Nanofiber Mat using Pycnometer in Filtration

Electrospun Polymer nanofibers have a wide range of applications including automotive air filters. Large surface area, small pores, flexible and adequate porosity are widely recognized as important parameters for improving the performance of the filter media and therefore measuring the porosity of the medium is extremely important. Porosity measurement techniques such as density based method, mercury porosimetry, capillary flow porometry, image analysis are relatively inaccurate and they have some disadvantages for measuring the porosity of the nano fibers. In the present study porosity measurement for nanofiber mat using pycnometer was explored. Pycnometer is generally used to measure the density of the solids of having volumes upto 150 cc. Volume of the nanofiber was measured by pycnometer and porosity is determined as fraction of the void in total volume of the fiber. Total volume is calculated from FESEM image thickness. Various advantages of pycnometry method when compared to other techniques were discussed based on the results of porosity measurements of nanofiber mats.