Annual variation of air-water temperature difference at three Estonian coastal stations

2013 ◽  
Vol 19 (4) ◽  
pp. 329
Author(s):  
S Keevallik
Keyword(s):  
Water Temperature ◽  
Temperature Difference ◽  
Annual Variation

scholarly journals The effect of a sudden temperature decrease on selected physiological indices in the common carp

2020 ◽  
Vol 65 (No. 8) ◽  
pp. 346-357
Author(s):  
N Hodkovicova ◽  
J Mares ◽  
P Sehonova ◽  
J Blahova ◽  
M Faldyna ◽  
...  
Keyword(s):  
Water Temperature ◽  
Mononuclear Cell ◽  
Temperature Difference ◽  
Skin Necrosis ◽  
Temperature Decrease ◽  
Mononuclear Cell Infiltration ◽  
Lymphocyte Ratio ◽  
Temperature Group ◽  
Biochemical Indices ◽  
Haematological Indices

The objective of the study was to evaluate stress invoked by a temperature decrease in the common carp (n = 56). After acclimatisation to laboratory conditions at a temperature of 27.8 ± 1.0 °C, the fish (n = 28) were transferred to 16.8 ± 1.0 °C water (group T2; temperature difference Δ –11 °C); the rest of the fish were kept at the original water temperature (group T1). The examination of individual fish was made after 6, 12, 24 and 48 hours (h). The impact on the haematological and biochemical indices was evaluated. Furthermore, the effect on the food content passage speed was investigated and a histopathological examination was performed. The changed haematological indices in the T2 group returned to the T1 values 48 h after a temperature decrease, except for the neutrophil-lymphocyte ratio which was found to be higher in all the T2 samplings. Most of the monitored biochemical indices decreased in the T2 group and some of them remained that way at 48 hours. On the contrary, the liver enzymes increased in the T2 group at 48 hours. The passage of food through the digestive tract was mostly finished after 48 h for both groups. However, in the warmer water, the intestine was empty in 71.4% cases after 24 h already, while in the T2 group, the food content passage was only completed in 14.3% of the fish at the same time. Local gill and skin necrosis, and mononuclear cell infiltration were found in the T2 group. A sudden change in the temperature can affect various parameters of the common carp, however, these changes can mostly be eliminated within 48 hours.

RESULTS OF LONG-TERM RADON MONITORING IN THE TYPICAL SLOVAK FAMILY HOUSE—A CASE STUDY

2020 ◽  
Vol 191 (2) ◽  
pp. 223-227
Author(s):  
Monika Müllerová ◽  
Karol Holý ◽  
Jozef Masarik
Keyword(s):  
Temperature Difference ◽  
Annual Variation ◽  
Activity Concentration ◽  
The Other ◽  
Outdoor Air ◽  
Family House ◽  
Radon Monitoring ◽  
Indoor And Outdoor

Abstract This case study provides a view of the behavior of radon in an uninhabited house, the likes of which were built in thousands in Slovakia between 1950 and 1990. In one room of the house that was in contact with the subsoil, an average annual radon activity concentration (RAC) as high as 1088 Bq m−3 was found. A high radon supply to this room from the subsoil was identified in the corner of the room, and this correlated very well with the temperature difference between indoor and outdoor air. In this room, an atypical annual variation of RAC was found, with a maximum in September (1600 Bq m−3). In the other rooms on the ground floor, RACs at the level of 400–500 Bq m−3 were detected. In the rooms on the first floor, RACs of up to ~200 Bq m−3 were found.

scholarly journals Annual Variation of Water Temperature, Salinity, and Dissolved Oxygen in Aburatsubo Bay (2)

1930 ◽  
Vol 6 (10) ◽  
pp. 1466-1481
Author(s):  
S. Yoshimura ◽  
N. Yoshii ◽  
S. Kojima
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Annual Variation

Finite element prediction of temperature gradients in walls of cylindrical concrete storage structures

1991 ◽  
Vol 18 (1) ◽  
pp. 12-19 ◽  
Author(s):  
J. C. Jofriet ◽  
S. Jiang ◽  
S. W. Tang
Keyword(s):  
Finite Element ◽  
Water Temperature ◽  
Temperature Difference ◽  
Water Reservoir ◽  
Cylinder Wall ◽  
Temperature Load ◽  
Design Values ◽  
Storage Structures ◽  
Winter Water Temperature ◽  
Finite Element Prediction

Aboveground concrete cylindrical storage tanks must be designed for temperature differences between inside and outside faces of the wall. The stresses in the cylinder wall are a linear function of the temperature difference. A number of transient heat transfer finite element analyses were carried out to determine reasonable design values for this temperature difference. Extreme summer and winter conditions for southern Ontario were assumed in the analyses. It was found that for water stand-pipes supplied by groundwater the temperature difference can be as high as 25 °C, based on a summer water temperature of 10 °C. The maximum winter temperature difference was also 25 °C, based on a winter water temperature of 5 °C. For farm tower silos, a design temperature difference of 15 °C is probably more appropriate. Storage structures for other liquids can be judged if the temperature of the contained liquid is known. Key words: standpipes, structural design, temperature load, water reservoir, finite element prediction.

Vertical Thermal Distribution at the near Dam Region of the Three Gorges Reservoir in the Initial Impoundment Period

2014 ◽  
Vol 889-890 ◽  
pp. 1649-1652
Author(s):  
L.Q. Dai ◽  
H.C. Dai ◽  
B.W. Wang
Keyword(s):  
Temperature Distribution ◽  
Water Temperature ◽  
Temperature Difference ◽  
Three Gorges Reservoir ◽  
Thermal Structure ◽  
Maximum Temperature ◽  
Three Gorges ◽  
Bottom Water Temperature ◽  
The Three Gorges Reservoir ◽  
The Three Gorges

Water temperature plays a crucial role in water ecological environment both in the reservoir and downstream area. Three Gorges Project (TGP) is the largest hydraulic engineering in the world, and changes of water quality attract much more attention, especially in the thermal structure since initial impoundment in 2003. In order to clearly understand water temperature distribution after the initial impoundment in the Three Gorges Reservoir (TGR), we monitored the temperature distribution of the Taipingxi section which was not far from the dam from early April to the end of July in 2004. According to the analyzing of the monitoring data of transverse and vertical temperature variation, we could find that when water level went up to 135m above sea level (a.s.l.) or 139m in the initial impoundment phase, the temperature mixed uniformly in transverse direction. Excepting April, there was basically had no temperature difference in vertical direction, even in April, the maximum temperature difference was only 1.39°C within 100 meters (April 22), the average temperature gradient was only 0.014°C/m; Both the temperature of water and atmosphere have similar variation tendency, but the response of the water temperature to atmosphere is delayed, especially the bottom water temperature. The result indicate that the reservoir displayed a mixed thermal structure during initial impoundment phase, therefore, the release had no change before and after impoundment, also had little influence on the aquatic organism and crops at downstream , the work provide a scientific basis for the development of pollution control and ecological protection measure.

scholarly journals Experimental Investigation and Theoretical Analysis on the Performance of Tube-Sheet Photovoltaic Thermal (PV/T) Collectors

2021 ◽  
Vol 8 ◽  
pp. 45-58
Author(s):  
Guoqing Yu ◽  
Hongzhi Liu ◽  
Wei Zhao ◽  
Gaojie Yang
Keyword(s):  
Theoretical Analysis ◽  
Thermal Resistance ◽  
Water Temperature ◽  
Temperature Difference ◽  
Electricity Generation ◽  
Large Temperature ◽  
Transfer Model ◽  
Tube Sheet ◽  
Daily Average ◽  
Pv Panel

The PV/T collectors realize the simultaneous output of electricity and thermal energy, which are more efficient than the separated photovoltaic (PV) or solar thermal collectors. In this paper, the electricity generation and thermal collection performances of tube-sheet PV/T collector are studied. The main research contents are as follows: an experimental test system of PV/T collector was built to test the electricity generation and thermal collection performances of tube-sheet PV/T at an inlet water temperature of 30°C. Moreover, the flow resistance test was carried out. In addition, the theoretical heat transfer model was established, and the thermal performance was calculated by theoretical analysis. The experimental data showed that the daily average temperature difference between the PV panel and the inlet water temperature was about 22.5°C. The daily average electrical efficiency was about 9.25%, and the daily average thermal efficiency was about 28.67%. The theoretical analysis of the tube-sheet PV/T model was carried out, and the calculated results were close to the experimental results. The main reason for the large temperature difference between the PV panel and water temperature was that the combined thermal resistance between the PV panel and the absorber plate was large, and reducing the combined thermal resistance could reduce the temperature of the PV panel. The effects of solar irradiance, ambient temperature and spacing of row tubes on the performance of thermal collection were analyzed to optimize the PV/T performance.

Analysis on Heat Transfer Energy Efficiency of U-Tube Buried Pipe under Variable Entering Water Temperature Conditions

2014 ◽  
Vol 960-961 ◽  
pp. 603-608
Author(s):  
Yu Zhou Cui
Keyword(s):  
Heat Transfer ◽  
Energy Efficiency ◽  
Water Temperature ◽  
Heat Pump ◽  
Temperature Difference ◽  
Heat Extraction ◽  
Ground Source Heat Pump ◽  
Buried Pipe ◽  
Ground Source ◽  
Heat Transfer Capacity

Taken as the carrier of heat extraction between rock-soil body and ground source heat pump systems, U-tubed pipe heat transfer efficiency was the key for ensuring the long-term and high-performance operation of ground source heat pump systems by means of improving the heat transfer effect. The efficiency coefficient, E, is defined as the ratio of the actual heat transfer capacity to the theoretically maximal heat transfer capacity from the U-tube into rock-soil body, which illustrated the effect of heat transfer ability and the variable heating or cooling loads. Aim at Variation characteristics of heat transfer coefficient of energy efficiency under the variable temperature inflow condition, decomposed into the product of the ratio of biggest buried tube heat transfer temperature difference φ and heat pump outlet water temperature difference σ. Use of u-shaped buried pipe three-dimensional heat transfer model which based on the multipole theory, the influence law of its change which caused by the construction load, buried pipe flow and the unit performance were analyzed, it can provide technical support to optimize the design of ground source heat pump system.

Sign in / Sign up

Export Citation Format

Share Document