Discharge Ends Research Articles

An in situ method to compare the potential for periphyton productivity of lotic habitats

A simple field method for measuring relative net productivity in flowing waters is described. To assess its sensitivity and practicality, the eutrophication potential of a tertiary sewage treatment plant effluent was assayed on the Fort River of Amherst, Massachusetts. Two sets of three 10 m lexan tubes (1.25 cm i.d.) were anchored to the river bed 100 m upstream and downstream from the sewage plant outfall. Data collection began following a 2 week colonization period for the periphyton community. Substrate primary productivity (mg O 2 min −1) was determined by subtracting inflow dissolved oxygen concentrations from these levels at the discharge ends of each tube and multiplying the difference by the flow rate. The downstream tubes demonstrated an enhanced response at a 0.01 level of significance to an increment of 0.005 and 0.1 ppm of phosphorous and nitrogen respectively. Data analysis revealed a highly significant regression of the net productivity on stream flow which was adjusted for by an analysis of covariance. The productivity of the downstream station was distinctly higher (0.4522 mg O 2 min −1) then the value of the upstream station (0.2584 mg O 2 min −1). The protocol thus affords a biological summation of the sewage effluent through comparison with the control station replicates.

Eliminating dust at the discharge ends of KZ-200 sintering machines

Eliminating dust at the discharge ends of KZ-200 sintering machines

“Puffing” inSclerotinia sclerotiorumandS. minor

Abstract When Sclerotinia sclerotiorum apothecia “puff”, the race of discharge of ascospores increases rapidly to a maximum which is maintained briefly and then declines gradually; individual asci continue to dehisce for several seconds after the main discharge. The discharge of S. minor apothecia is more ephemeral: the maximum discharge race appears to be reached as soon as the puff starts, and the discharge ends abruptly.

TIME DEPENDENCE OF THE POWER OUTPUT AT 337 μ IN A CN LASER

The time dependence of the laser output pulse at 337 μ in an acetone and nitrogen gas mixture has been studied using a fast indium antimonide detector. Current pulses from a line-type modulator were varied in length from 2 to 20 μsec with amplitudes from 50 to 180 A. The start of the laser output pulse occurred after the current pulse in the discharge was over, from 6 to 8 μsec after the end of the current pulse. These results indicate that, for the currents used, population inversion and the achievement of conditions allowing laser action, take from 6 to 8 μsec after the discharge ends to become established.