Determination of the viscous characteristic length in air‐filled porous materials by ultrasonic attenuation measurements

Determination of the viscous characteristic length in air-filled porous materials by ultrasonic attenuation measurements

Determination of ultrasonic parameters based on attenuation and dispersion measurements.

In the measurement of acoustic attenuation that obeys a power-low alpha = beta f, the traditional through-transmission method uses only the amplitude information of the recorded pulses to determine the two parameters, beta and n. In this paper, we propose a new method that utilizes both the amplitude and phase information of the pulses to determine the two parameters. According to this method, ...

study of cohesive devices in the textbook of english for the students of apsychology by rastegarpour

this study investigates the cohesive devices used in the textbook of english for the students of psychology. the research questions and hypotheses in the present study are based on what frequency and distribution of grammatical and lexical cohesive devices are. then, to answer the questions all grammatical and lexical cohesive devices in reading comprehension passages from 6 units of 21units th...

Determination of biomass concentration by measurement of ultrasonic attenuation

Experimental results are presented that demonstrate that ultrasonic attenuation can be used to estimate the biomass concentration of a biological suspension. The attenuation approach avoids the temperature sensitivity of established ultrasound velocity test methods, which have hindered their application in process environments. An empirical model is presented for the estimation of the biomass o...

the effect of authentic listening materials on the listening proficiency of efl learners in the intermediate level

having conducted the experiment and analysed the data, the researcher computed the groups mean scores and variances for the test relating to the research question. as the final atep, a t-test was conodonted for the hypothesis. as noted earlier, the significance level was determined at .05 and .01 respectively. the observed t-value was higher than the critical t-value at. 5 and .01 levels. conse...