Fiber-optic Doppler Anemometer Research Articles

Laser measurement of the motility of bull spermatozoa in an egg-yolk diluent.

An objective method of assessing bull sperm motility by specifying the mean swimming speed and number of motile spermatozoa in a sample is described. Laser light was conducted into diluted semen samples using a fibre-optic Doppler anemometer (FODA). The signal correlation of the back-scattered laser light was modelled using least squares computer curve fitting of the resulting data. Agreement was found between the mean swimming speeds obtained and those measured using time lapse photography.

The measurement of sperm motility by the fibre optic Doppler anemometer as a prediction of bovine fertility

The fibre optic Doppler anemometer (FODA) has been used to develop an accurate quantitative method of routinely assessing bull fertility. This method is of importance to the artificial insemination industry because the present qualitative estimation, performed by viewing semen using a microscope, can only set broad limits of quality. Laser light from the FODA was directed into diluted semen samples and the back scattered light was measured. A digital correlator was used to calculate the signal correlation of the back scattered light. The resultant data curves were interpreted in terms of the collective motility and swimming speed of the spermatozoa using a microcomputer. These two parameters are accepted as being indicative of fertility. The accuracy of this method is demonstrated by examination of results obtained in an experiment where enzymes, thought to alter fertility, were added to semen. The effect of the enzymes on the swimming speed and motility was clearly demonstrated.

Size and concentration of particles in syton using the fiber optic Doppler anemometer, FODA

The fiber optic Doppler anemometer, FODA, utilizes laser light directed into a communication-type optical fiber to obtain a heterodyne measurement of scattered light from an object or objects near the tip of the fiber. The FODA is applied in this paper to the measurement of the Brownian motion of a colloidal suspension of submicron particles, Syton W-30. By comparison of the power spectrum of scattered light with appropriate mathematical models, it is possible to determine the size distribution of the particles of the colloid. In addition, the concentration of particles in the colloid may be determined from the mean square photocurrent of the FODA. The accuracy of the FODA was assessed by verifying the assumption of heterodyne detection and by determining the noise and signal-to-noise ratio of the instrument. The accuracy of the particle size distribution determination with the FODA was tested by comparing it with that obtained from electron microscope photographs of the particles in Syton. It was found that the laser-scattering size distribution obtained with the FODA is strongly affected by the scattering amplitude of the spherical particles in Syton, since large particles scatter more light than do small ones. A method of obtaining the true particle size distribution, from the laser-scattering size distribution was shown to yield accurate results, within the statistical accuracy of the data.

The determination of the mean and standard deviation of the size distribution of a colloidal suspension of submicron particles using the Fiber Optic Doppler Anemometer, FODA

Laser light-scattering measurements of the Brownian motion of a colloidal suspension of silica particles, Syton, by means of the Fiber Optic Doppler Anemometer (FODA) were used to determine the mean and standard deviation of the particle size distribution. Measurements over a wide range of concentrations from undiluted Syton to 0.049% Syton solution showed a consistent power spectrum of scattered light amplitude fluctuations. Using a modified Lorentzian model for the power spectrum, a computer least-squares curve fit and a graphical method were used to calculate the mean and standard deviation of particle radius. The results were consistent for all concentrations of Syton, verifying the versatility of the FODA and the accuracy of the modified Lorentzian model. The mean and standard deviation of particle radius in Syton were found to be 46.5 and 20.8 nm, respectively. It was found that clumping in undiluted Syton caused an apparent increase in the mean and standard deviation of the particle size distribution, as compared with all of the other dilutions where clumping did not occur.