Airflow method

Results such as those reported in Table I are clearly unacceptable. It was decided that the airflow method would ultimately be the most accurate and the most versatile so the attempts at improving the methodology began with a critical examination of the apparatus pictured in Figure I. 

The indirect methods are characterized by the need to be rapid as well as accurate and be reliable enough to be used in the cotton marketing system. These methods may be divided into the double compression airflow approach and near infrared reflectance spectroscopy (NIRS). Examples of the former (airflow) method are the Shirley Developments Fineness and Maturity Tester (FMT) [575], and the Spinlab Arealometer [576]. The NIRS approaches have been developed and discussed by Ghosh [577] and Montalvo et al. [578]. 

Later work on this aspect reported by Scott et al. [5] claimed correlations of 0.9 against one of the standard methods, the fiber-diameter-by-airflow method [6]. Unfortunately these encouraging results were obtained only with clean fiber working with greasy fiber the correlation fell to. 74. 

In the alternating airflow method, a piston is used to generate a low frequency alternating airflow through the test specimen and a condenser microphone is used to obtain the root mean square (rms) value of the pressure change in front of the porous material. Fig. 5.2 shows the basic principle of the experiment setup. 

In the alternating airflow method, a piston is used to generate a low frequency alternating airflow through the test specimen and a condenser microphone is used to obtain... 

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