scholarly journals LONG-TERM AND SHORT-TERM SIMULATIONS OF WATER STRUCTURE IN ISE BAY AREA USING AIR-SEA-WATER QUALITY COUPLED MODEL

2015 ◽  
Vol 71 (2) ◽  
pp. I_371-I_376
Author(s):  
Kazuki SUZUKI ◽  
Koji KAWASAKI ◽  
Hidehisa OKAMOTO ◽  
Tomokazu MURAKAMI

The term ‘pollution’ is taken in its broadest sense and effects are recognized to be due to interference, tainting and toxicity. Each of these types of impact is discussed and assessed. It is concluded that no long-term adverse effects on fish stocks can be attributed to oil but that local impacts can be extremely damaging in the short term and that produce from specific localities can be tainted and unmarketable for long periods. In some coastal areas oil can be one among several contributors to reduced water quality, and the implications of this are discussed.


Kerntechnik ◽  
2021 ◽  
Vol 86 (2) ◽  
pp. 128-142
Author(s):  
J.-J. Huang ◽  
S.-W. Chen ◽  
J.-R. Wang ◽  
C. Shih ◽  
H.-T. Lin

Abstract This study established an RCS-Containment coupled model that integrates the reactor coolant system (RCS) and the containment system by using the TRACE code. The coupled model was used in both short-term and long-term loss of coolant accident (LOCA) analyses. Besides, the RELAP5/CONTAN model that only contains the containment system was also developed for comparison. For short-term analysis, three kinds of LOCA scenarios were investigated: the recirculation line break (RCLB), the main steam line break (MSLB), and the feedwater line break (FWLB). For long-term analysis, the dry-well and suppression pool temperature responses of the RCLB were studied. The analysis results of RELAP5/CONTAN and TRACE models are benchmarked with those of FSAR and RELAP5/GOTHIC models, and it appears that the results of the above four models are consistent in general trends.


1994 ◽  
Vol 194 (1) ◽  
pp. 47-68
Author(s):  
A L Silva ◽  
S H Wright

Long-term acclimation of Mytilus californianus to 60% artificial sea water (585 mosmol l-1; ASW) led to a 30-40% decrease in the taurine (53.5-36.9 mumol g-1 wet mass) and betaine (44.8-26.2 mumol g-1 wet mass) content of gill tissue, compared with that of control animals held in 100% ASW (980 mosmol l-1). The K+ content of gills did not change following long-term acclimation to reduced salinity. In contrast, losses of all three solutes during a brief (60 min) exposure to 60% ASW were less than or equal to 15%. Nevertheless, the swelling of gill cells that occurred after acute exposure to 60% ASW was followed by a return towards the control volume. Direct optical measurement of single gill filaments confirmed that, during an acute exposure to reduced salinity, ciliated lateral cells increased in cell height (volume) and then underwent a regulatory volume decrease (RVD) with a half-time of approximately 10 min. This short-term RVD was completely inhibited by exposure to 1 mmol l-1 quinidine, a K+ channel blocker, but only when the drug was applied to the basolateral aspect of the gill epithelium. Application of 1 mumol l-1 valinomycin relieved the inhibition by quinidine of the gill RVD. However, addition of valinomycin did not accelerate the rate of RVD observed in the absence of quinidine. These results indicate that long-term acclimation of Mytilus californianus gill in dilute sea water involves primarily losses of taurine and betaine, whereas short-term regulation of cell volume may involve an electrically conductive loss of intracellular K+ and a counter ion.


2004 ◽  
Vol 8 (3) ◽  
pp. 422-435 ◽  
Author(s):  
S. J. Langan ◽  
D. Hirst

Abstract. A long term record of water chemistry, consisting of twenty years of weekly spot samples, from three sub-catchments draining into a loch and the loch outflow in Galloway, S.W. Scotland have been analysed. The analysis undertaken consisted of a three component statistical trend model. The technique allows the identification of long-term, seasonal and short-term trends, as well as differentiation between base flow and high flow responses. The land usage in the three sub-catchments is moorland, forest and forest plus lime. The results show that, since the mid-1980s, there has been a gradual decline in stream-water sulphate of the same order as reductions in the deposition of non-marine sulphate. Superimposed on this trend are somewhat random but considerable perturbations to this decline, caused by sea-salt deposition. There is no evidence of changes in surface water nitrate concentrations. The influence of different land management is evident in the sulphate, nitrate and pH data, whilst variations in calcium concentrations are also a product of differences in hydrological routing and the impact of sea-salt episodes. Keywords: trend analysis, acid deposition, land management, water quality, sea-salts, Galloway, S.W. Scotland


2009 ◽  
Vol 9 (1) ◽  
pp. 99-105 ◽  
Author(s):  
I. Slavik ◽  
W. Uhl

Reservoir water for drinking water production may undergo major short-term and long-term quality changes. These are results of natural processes in the water body and of the water's quality entering and leaving the reservoir. Long term quality changes are due to management of catchment areas, but also to a considerable extent by external impacts like climate change. Short term quality changes are impacted by extreme events like rain storms after drought periods, which might also be a result of climate change. Furthermore, short- and mid-term quality changes are impacted by reservoir management, which also influences the ecological state of rivers downstream the reservoir. The purpose of our work is to develop a decision support tool for reservoir management which takes into account short-, mid- and long-term factors for water quality change. With the tool it is intended to simulate not only water quality, but also management impact on flood risk prevention and drinking water quality (treatment efficiency and costs) and to assist decision making for reservoir management.


Factors causing global degradation of coral reefs are examined briefly as a basis for predicting the likely consequences of increases in these factors. The earlier consensus was that widespread but localized damage from natural factors such as storms, and direct anthropogenic effects such as increased sedimentation, pollution and exploitation, posed the largest immediate threat to coral reefs. Now truly global factors associated with accelerating Global Climate Change are either damaging coral reefs or have the potential to inflict greater damage in the immediate future: e.g. increases in coral bleaching and mortality, and reductions in coral calcification due to changes in sea-water chemistry with increasing carbon dioxide concentrations. Rises in sea level will probably disrupt human communities and their cultures by making coral cays uninhabitable, whereas coral reefs will sustain minimal damage from the rise in sea level. The short-term (decades) prognosis is indeed grim, with major reductions almost certain in the extent and biodiversity of coral reefs, and severe disruptions to cultures and economies dependent on reef resources. The long-term (centuries to millennia) prognosis is more encouraging because coral reefs have remarkable resilience to severe disruption and will probably show this resilience in the future when climate changes either stabilize or reverse.


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