Discharge Stations Research Articles

Perturbed Flow Structure in an Annular Seal Due to Synchronous Whirl

This paper provides a thorough examination of the flow field resulting from synchronous whirl of an eccentric rotor in an annular seal under typical operating conditions. A new finite-element-based perturbation model is employed in the analysis, whereby perturbations in the flow thermophysical properties are attributed to virtual distortions in the rotor-to-housing finite element assembly. The numerical results are compared to a recent set of experimental data for a hydraulic seal with typical geometrical configurations and a synchronously whirling rotor. Despite the common perception that perturbation analyses are categorically confined to small rotor eccentricities, good agreement between the computed flow field and the experimental data is obtained for an eccentricity/clearance ratio of 50 percent. The agreement between the two sets of data is notably better at axial locations where the real-rig flow admission losses have diminished, and up to the seal discharge station. This attests to the accuracy of this untraditional and highly versatile perturbation model in predicting the rotordynamic characteristics of this and a wide variety of conceptually similar fluid/rotor interaction problems.

Hydrometric Network Evaluation: Audit Approach

An evaluation of the hydrometric network of New Brunswick was performed starting from basic principles of hydrometric network design and proceeding through the analysis of the present network and its ability to meet user needs. Discharge stations used to monitor the streamflow component of the regional hydrology are assessed on their ability to contribute to the transfer of information to ungauged sites. A survey was conducted to determine users' needs. The results of the various analyses are combined using an audit approach based on selected rating factors. The final output includes specific network improvements designed to satisfy hydrometric needs. These improvements are presented in the form of a list of network adjustment scenarios that are available as a management guide. A summary of the approach and major findings is presented.

Le Rhône supérieur franco-suisse : fluctuations naturelles et artificielles du régime fluvial

Abstract. — Large hydrometric developments in the upper Rhône valley in Switzerland and France, have notably modified monthly discharge rates. By comparing various observation periods, from the 19 th century until to day, it is possible to determine the respective proportions in the discharges due to climatic fluctuations and anthropological changes. These modifications will be studied at the discharge stations of Porte du Scex, Genève and Sault Brenaz.

Use of an in situ artificial substrate for biological accumulation and monitoring of aqueous trace metals a preliminary field investigation

A preliminary field study was undertaken to investigate the use of attached periphyton on an artificial substrate as a water column composite sampler for trace metals. Spatial and temporal trends are presented of trace metal biological accumulation terms of the substrate placement in the vicinity of a synthetic fiber chemical manufacturing plant. Seasonal distribution and biological accumulation of antimony, chromium, copper, mercury and zinc is discussed. Statistical analysis of metal accumulated as a function of substrate placement, showed significantly higher levels of chromium for the discharge station compared to the reference stations. In contrast sediment analysis of the discharge station showed only slightly higher levels of zinc and no significant chromium accumulation when compared to a upriver reference station.

Macroinfaunal structure and effects of thermal discharges in a mesohaline habitat of Chesapeake Bay, near a Nuclear Power Plant

The soft-bottom macroinfauna of the Chesapeake Bay near the Calvert Cliffs Nuclear Power Plant, Maryland, USA, was studied quarterly in 1977. A total of 42,900 organisms distributed among 55 taxa was taken in 180 Smith-McIntyre grabs. Two communities and an ecotone between these two communities were identified in association with three sediment types: sand, sand-clay, and clay. Reproductive activities of 8 numerically dominant species are described. The macroinfauna at Calvert Cliffs was largely seasonal; species richness and organism abundances were lowest in late summer. The polychaetes Scolecolepides viridis and Heteromastus filiformis and the bivalves Macoma balthica and Mya arenaria were dominant in March-June. In September-December, the polychaetes Neanthes succinea, Paraprionospio pinnata, and Glycinde solitaria and the bivalve Gemma gemma became dominant. There were clear indications of differences associated with sediment types in total number of species, total number of individuals, and abundances of the dominant species. The shallower and intermediate habitats had higher sand-clay ratios, lower organic carbon contents, and larger numbers of organisms than the deeper clay habitat. Within each depth, no apparent detrimental effects caused by the thermal discharges on total number of species, total number of individuals, abundances of the dominant species, species diversity or evenness were found. Increased abundance was observed at the discharge stations for a few species, especially for Mya arenaria and N. succinea.

Some Effects of a Power Plant Effluent on Estuarine Epibenthic Organisms

AbstractA study using the submerged test panel method was conducted at the Oyster Creek Nuclear Generating Station near Barnegat Bay, New Jersey to investigate effects of the heated effluent on epibenthic communities. Test panels were placed in the intake and discharge canals and collected using SCUBA at 28, 84, 168 and 335‐day intervals between October 1970 and October 1971. Exposed panels were replaced by clean panels upon collection.Faunal resemblance, both between stations during a sampling date and within stations from one sampling date to the next, was low. Numbers of species were higher at the discharge station than at the intake station from late fall to early summer and lower from midsummer to early fall. Overall differences in diversity at the two stations could not be detected. The optimum temperature for growth of Balanus sp. was approached more closely during winter in the discharge canal than in the intake canal where growth was retarded by cold water. Balanus eburneus appeared to have an extended breeding season. Because of dilution of the discharged water with cooler intake water through a plant bypass system during the summer, the effluent was not seriously harmful to amphipod reproduction. Season abundances of numerous invertebrates at both stations are reported and possible power plant effects are discussed.

The effects of power plant condenser cooling water entrainment on the amphipod. Gammarus sp.

The abundant Hudson River amphipod Gammarus sp. was examined for viability before and during entrainment in the Indian Point cooling water system. The mean per cent survivial of Gammarus sp. sampled during ΔT's of 7.1–8.3°C and ambient temperatures of 24.9–26.0°C was 98.5 and 97.4 per cent for the two intake stations and 90.1 and 96.8 per cent for the discharge canal stations D-1 and D-2 respectively. A statistically significant ( α = 0.05) difference was detected between the survival of Gammarus sp. at the intake stations and discharge station D-1. located near the upper end of the discharge canal. Entrained Gammarus sp. experience increased initial and latent mortalities during periods of condenser chlorination. Comparison of the abundances of entrained Gammarus sp. during day and night sampling periods reveals a significantly higher occurrence during darkness. Temperature bioassays indicate that the thermal tolerance of Gammarus sp. is dependent on exposure time and ambient temperature. The temperature resulting in a 50 per cent mortality of Gammarus sp. for 30 min exposure times increased approximately 11 C as ambient temperatures increased from 2.5 to 25.8°C. Consequently, Gammarus sp. was capable of surviving ΔT's of greater magnitude as the ambient temperature to which they were acclimated decreased. Temperature bioassays indicated that Gammarus sp. should be able to tolerate all projected time-temperature exposure combinations encountered during entrainment through the cooling water system.

VARIABILITY OF SEASONAL AND ANNUAL RUNOFF IN NORWAY

A preliminary map of variability of annual runoff in Norway has been prepared based on estimates of the coefficient of variation cv for 56 non-regulated discharge stations having more than 35 years of continuous observations. The regional pattern of cv reflects the altitude and possibly also the different precipitation regimes of Norway; low variability characterizes the wet western part of the country where frontal precipitation dominates, and relatively high variability typifies the drier South-Eastern Norway where considerable amounts of convective precipitation are common. cv for annual runoff is slightly affected by catchment area. Variability of monthly runoff also shows a regional pattern which is interpreted in terms of runoff regime characteristics.

Coding for Selective Discharge from Overhead Chain Conveyors

The paper will give particulars of methods of coding used in conjunction with overhead chain conveyors for selective discharge. An installation is then described for the sorting of mail bags from a storage area into numerous positions where discharge is effected into British Railway Universal Trolleys for transport by rail. After the final loading position, the destination code, which is indicated by a label attached to the mail bag, is keyed into an electronic memory, which in turn activates the selected discharge station at the appropriate time, thereby automatically releasing the bag directly into the appropriate trolley.

Glacier mass budget measurements by hydrologic means

Ice storage changes for the South Cascade Glacier drainage basin were determined for the 1957–1964 period using basin runoff and precipitation measurements. Measurements indicate that evaporation and condensation are negligible compared with the large runoff and precipitation values. Runoff, measured by a stream discharge station, averaged 4.04 m/yr; precipitation, determined by snow accumulation measurements at a central point on the glacier and by storage gages, averaged 3.82 m/yr, resulting in a basin net loss of about 0.22 m/yr. During the same period, South Cascade Glacier net budgets were determined by ablation stakes, snow density‐depth profiles, and maps. The average glacier net budget for the period was −0.61sol;yr of water. This amount is equivalent to −0.26 m of water when averaged over the drainage basin (43% glacier‐covered), which is in fair agreement with the net storage change measured by hydrologic methods. Agreement between the two methods for individual years is slightly less perfect. (Key words: Glaciers; water balance.)