Simple Air-Permeability Method for Measuring Surface Areas of Fine Powders

1954 ◽  
Vol 26 (10) ◽  
pp. 1623-1630 ◽  
Author(s):  
H. J. Kamack
Keyword(s):  
Air Permeability ◽  
Fine Powders ◽  
Surface Areas ◽  
Measuring Surface ◽  
Permeability Method

TEM measurement of surface area of automotive catalysts

1994 ◽  
Vol 52 ◽  
pp. 776-777
Author(s):  
M. H. Yao ◽  
D. R. Liu ◽  
R. J. Baird ◽  
R. K. Usmen ◽  
R. W. McCabe
Keyword(s):  
Electron Microscopy ◽  
Surface Area ◽  
Average Particle Size ◽  
Weighted Average ◽  
Average Particle ◽  
Automotive Catalysts ◽  
Surface Areas ◽  
Measuring Surface ◽  
Major Factors ◽  
Average Size

The specific surface area of supported noble metal particles in an automotive catalyst is defined as the exposed surface area per unit mass of these particles. It is of great importance to know this parameter, since this is one of the major factors that determine the effectiveness of the catalyst. Commonly used methods for characterizing catalysts, such as X-ray diffraction and TEM, do not directly provide a measure of surface area, but, instead, provide a measure of the “average size” of supported particles. Moreover, the “average sizes” obtained from different experimental techniques are often not comparable. Furthermore, many previous electron microscopy catalyst studies measured only simple average particle size, and no detailed procedure for measuring area-weighted average size or surface area appear to have been reported.In the current study, a procedure for measuring surface area of supported particles by transmission electron microscopy(TEM) was developed, and applied to measure surface areas of various production three-way automotive catalysts.

A Semi-Empirical Method for Estimating the Effective Leak and Vent Areas of an Airbag

1999 ◽  
Author(s):  
Aloysius U. Anagonye ◽  
J. T. Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Air Permeability ◽  
Empirical Method ◽  
Test Apparatus ◽  
Element Analysis ◽  
Test Setup ◽  
Surface Areas ◽  
Semi Empirical ◽  
Fabric Specimen

Abstract A semi-empirical method that utilizes tests from a small fabric specimen to quantify the effective leak and vent areas of an entire airbag is developed in this paper. The test setup and procedure used in the airbag material coupon tests are similar to the standard method used in determining air permeability of fabrics. A test apparatus for measuring the deflection of the fabric coupon was devised. Finite element analysis is used to compute the expanded vent and airbag surface areas of the coupon under various deformations. The leak and vent models were developed based on the results of a regression analysis. The effective vent area of a fabric coupon is a function of the ratio of the pressures across the fabric and the expanded vent area. Similarly, the effective leak area of a fabric coupon is a function of the ratio of the pressures across the fabric and the expanded surface area. The tested airbag materials were characterized with these models for use with finite element airbag models.

A Low-Cost, Rapid Method for Determining Carbon Black Surface Area

1983 ◽  
Vol 56 (2) ◽  
pp. 440-449 ◽  
Author(s):  
Jerry B. Pausch ◽  
Caroline A. McKalen
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
Low Cost ◽  
Control Procedure ◽  
Simple Method ◽  
Surface Areas ◽  
Measuring Surface ◽  
Headspace Gas ◽  
Black Surface ◽  
Area Data

Abstract For practical use of this method as a quality control procedure for carbon black, a combination of 4 mm3 and 6 mm octane doses appears to be the best compromise for a sample size of 0.1 g. These conditions cover well, a surface area range of 10–140 m2/g and surface areas up to 180 m2/g can be estimated. Larger doses of octane will extend the linear range on the high side, but the slope of the calibration curve is reduced significantly. A smaller slope yields lower precision. The regular testing of standards appears necessary to achieve optimum accuracy of surface area. At the present time, the method is calibrated against nitrogen surface area data, so the advantage of octane more closely simulating the rubber molecule is lost. We need to obtain adsorption isotherms that are better defined throughout the linear adsorption coefficient range for a number of carbon blacks, and thus become self-calibrated against octane. A more versatile dosing technique is preferred to enable these experiments to be run. An alternate approach is to correlate the headspace results with data obtained by other techniques such as CTAB. The advantages of automated headspace gas chromatography for measuring surface area have been outlined before . It is a rapid and simple method, which also exhibits relatively low labor involvement. The number of samples capable of being analyzed per day is significantly higher than by any other technique.

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