Biomedical subjects

H M Budman

Publications and source records attributed to H M Budman.

3 recordsLinked to original sources

PubMed2001

BOD5 estimation for pulp and paper mill effluent using UV absorbance.

A novel method based on UV absorbance, is presented for estimating the BOD5 in pulp and paper mill effluent. This method could eventually be incorporated into an on-line sensor for BOD5 that is suitable for process control applications. Two streams, the reactor entrance and the final effluent, from two different mills were studied. One mill employed the Kraft pulping process, while the second mill was a thermo-mechanical one. The absorbance over the range 200-350 nm showed significant differences between the two mills. Because the two mills use very distinct processes, separate correlations were used to relate the absorbance to the BOD5 for both the mills. Results indicate that prediction of reactor entrance BOD5 was reasonable, whereas prediction of final effluent BOD5 was inaccurate, for both mills. Also studied was the effect of aeration on BOD5 results obtained at low BOD5 values for the Kraft mill.

Industrial Waste↗

PubMed2000

Effect of temperature on the inhibition kinetics of phenol biodegradation by Pseudomonas putida Q5.

The temperature-dependent performance of mixed-culture wastewater treatment processes may be strongly influenced by their content of psychrotrophic bacteria. In this work, the effect of temperature on cell growth and phenol biodegradation kinetics of the psychrotrophic bacterium Pseudomonas putida Q5 were determined using both batch and continuous cultures in the range of 10-25 degrees C. The Haldane equation was found to be the most suitable substrate-inhibition model for the specific growth rate. The Haldane parameters mu(max) and K(I) were best modeled by a square-root dependency on temperature. However, the Arrhenius model provided a better prediction of the temperature dependence of K(S). The variation of the yield constant with temperature also was studied experimentally. Comparisons with results of previous workers are presented.

Biodegradation, Environmental↗

PubMed1991

Controlled freezing of nonideal solutions with application to cryosurgical processes.

Success of a cryosurgical procedure, i.e., maximal cell destruction, requires that the cooling rate be controlled during the freezing process. Standard cryosurgical devices are not usually designed to perform the required controlled process. In this study, a new cryosurgical device was developed which facilitates the achievement of a specified cooling rate during freezing by accurately controlling the probe temperature variation with time. The new device has been experimentally tested by applying it to an aqueous solution of mashed potatoes. The temperature field in the freezing medium, whose thermal properties are similar to those of biological tissue, was measured. The cryoprobe temperature was controlled according to a desired time varying profile which was assumed to maximize necrosis. The tracking accuracy and the stability of the closed loop control system were investigated. It was found that for most of the time the tracking accuracy was excellent and the error between the measured probe temperature and the desired set point is within +/- 0.4 degrees C. However, noticeable deviations from the set point occurred due to the supercooling phenomenon or due to the instability of the liquid nitrogen boiling regime in the cryoprobe. The experimental results were compared to those obtained by a finite elements program and very good agreement was obtained. The deviation between the two data sets seems to be mainly due to errors in positioning of the thermocouple junctions in the medium.

Analog-Digital Conversion↗