Application of membrane distillation in the management of thermal effluents from power plants

2019 ◽  
Vol 140 ◽  
pp. 35-41
Author(s):  
Youngkyu Park ◽  
Yongjun Choi ◽  
Sangho Lee
Keyword(s):  
Power Plants ◽  
Membrane Distillation ◽  
Thermal Effluents

Temperature selections of Anguilla japonica (L.) elvers, and their implications for migration

1991 ◽  
Vol 42 (6) ◽  
pp. 743 ◽  
Author(s):  
YL Chen ◽  
H Chen
Keyword(s):  
Thermal Gradient ◽  
Power Plants ◽  
Anguilla Japonica ◽  
Japanese Eel ◽  
Thermal Gradients ◽  
Temperature Selection ◽  
Naturally Occurring ◽  
Thermal Effluents ◽  
Stainless Steel Heat ◽  
Steel Heat

This study investigated the temperature selections of elvers of the Japanese eel, Anguilla japonica (L.), that had been acclimatized to various temperatures and salinities. The results provide information needed to assess the possible effects of thermal effluents from power plants and of naturally occurring thermal gradients on the freshwater migration and fishery harvest of elvers. A 7.14-m-long plastic pipe (i.d. 11 cm) fitted with two stainless-steel heat-exchange tubes was used for the study. The countercurrent design of the system provided a thermal gradient ranging from 11� C at one end of the pipe to 31� C at the other. Elvers could swim free of obstacles inside the pipe. They were acclimatized to 13, 15, 17, 19 or 21� C before being subjected to the thermal gradient. The distribution of elvers in the pipe was studied during a 24-h period. The results indicate that the temperature to which the elvers gravitated was higher than their acclimatization temperature for acclimatizaion temperatures between 13 and 21�C. The thermal preference of elvers acclimatized to salinities of 10 or 32 did not differ. The temperature- selection pattern of the elvers suggests that thermal effluents from power plants may not adversely affect the immigration of elvers.

scholarly journals Bacterioplankton Metacommunity Processes across Thermal Gradients: Weaker Species Sorting but Stronger Niche Segregation in Summer than in Winter in a Subtropical Bay

2018 ◽  
Vol 85 (2) ◽  
Author(s):  
Lijuan Ren ◽  
Xingyu Song ◽  
Dan He ◽  
Jianjun Wang ◽  
Meiting Tan ◽  
...  
Keyword(s):  
Microbial Ecology ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Gradients ◽  
Effluent Water ◽  
Species Sorting ◽  
Marine Bacterioplankton ◽  
Thermal Effluents ◽  
Thermal Effluent ◽  
Surrounding Seawater

ABSTRACT Thermal effluents from nuclear power plants greatly change the environmental and ecological conditions of the receiving marine water body, but knowledge about their impact on microbial ecology is limited. Here we used high-throughput sequencing of the 16S rRNA gene to examine marine bacterioplankton metacommunity assembly across thermal gradients in two representative seasons (i.e., winter and summer) in a subtropical bay located on the northern coast of the South China Sea. We found high heterogeneity in bacterioplankton community compositions (BCCs) across thermal gradients and between seasons. The spatially structured temperature gradient created by thermal effluents was the key determinant of BCCs, but its influence differed by season. Using a metacommunity approach, we found that in the thermal discharge area, i.e., where water is frequently exchanged with surrounding seawater and thermal effluent water, the BCC spatial patterns were shaped by species sorting rather than by mass effects from surrounding seawater or by dilution of thermal effluent water by surrounding seawater. However, this effect of species sorting was weaker in summer than in winter seawater. In both seasons, the bacterioplankton community structure was predominately determined by niche sharing; however, the relative importance of niche segregation was enhanced in summer seawater. Our findings suggest that for the seasonal differences in metacommunity processes, the BCCs of subtropical summer seawater were more sensitive to temperature and were more difficult to predict than those of winter seawater in the face of different intensities of thermal impacts. IMPORTANCE Understanding the mechanisms of bacterial community assembly across environmental gradients is one of the major goals of marine microbial ecology. Thermal effluents from two nuclear power plants have been present in the subtropical Daya Bay for more than 20 years and have generated a comparatively stable and long thermal gradient (a temperature increase from 0 to 10°C). The environmental patches across thermal gradients are heterogeneous and very strongly interconnected on a microbial scale; thus, this is a useful model for the study of the metacommunity processes (i.e., patch dynamics, species sorting, mass effects, and neutral processes) that underlie marine bacterioplankton assembly. The significance of our research is to reveal how environmental conditions and dispersal-related processes interact to influence bacterioplankton metacommunity processes and their seasonal differences across thermal gradients. Our results may advance the understanding of marine microbial ecology under future conditions of global warming.

Use of fractals to describe microstructures of porous thick-film platinum electrodes

1992 ◽  
Vol 50 (1) ◽  
pp. 314-315
Author(s):  
Steven D. Toteda
Keyword(s):  
Fractal Dimension ◽  
Power Plants ◽  
Electrical Response ◽  
Cubic Phase ◽  
Platinum Electrodes ◽  
Fine Grained ◽  
Impedance Response ◽  
Platinum Particles ◽  
Energy Surfaces ◽  
Highly Porous

Zirconia oxygen sensors, in such applications as power plants and automobiles, generally utilize platinum electrodes for the catalytic reaction of dissociating O2 at the surface. The microstructure of the platinum electrode defines the resulting electrical response. The electrode must be porous enough to allow the oxygen to reach the zirconia surface while still remaining electrically continuous. At low sintering temperatures, the platinum is highly porous and fine grained. The platinum particles sinter together as the firing temperatures are increased. As the sintering temperatures are raised even further, the surface of the platinum begins to facet with lower energy surfaces. These microstructural changes can be seen in Figures 1 and 2, but the goal of the work is to characterize the microstructure by its fractal dimension and then relate the fractal dimension to the electrical response. The sensors were fabricated from zirconia powder stabilized in the cubic phase with 8 mol% percent yttria. Each substrate was sintered for 14 hours at 1200°C. The resulting zirconia pellets, 13mm in diameter and 2mm in thickness, were roughly 97 to 98 percent of theoretical density. The Engelhard #6082 platinum paste was applied to the zirconia disks after they were mechanically polished ( diamond). The electrodes were then sintered at temperatures ranging from 600°C to 1000°C. Each sensor was tested to determine the impedance response from 1Hz to 5,000Hz. These frequencies correspond to the electrode at the test temperature of 600°C.

The Effects of Ion Implantation on the Surface Features of Inconel 600

1985 ◽  
Vol 43 ◽  
pp. 288-289
Author(s):  
John D. Rubio
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Nuclear Power ◽  
Power Plants ◽  
Surface Region ◽  
Selective Dissolution ◽  
Boundary Region ◽  
Near Surface ◽  
Inconel 600 ◽  
Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

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