Vertical Temperature Distribution in the Great Lakes

1952 ◽  
Vol 9 (7) ◽  
pp. 325-328 ◽  
Author(s):  
H. B. Hachey

On the basis of temperature observations made in the Great Lakes in the summer months it has been shown that: (a) the maximum depth of the thermocline does not exceed 50 feet, (b) the temperature gradient within the thermocline may be as much as 26 degrees Fahrenheit in 10 feet, (c) the thickness of the surface layer varies considerably with time and position, and can under certain circumstances be entirely removed from an area, and (d) the temperature of the deeper waters approximates to that of the maximum density of fresh water.

2020 ◽  
Vol 10 (6) ◽  
pp. 1980 ◽  
Author(s):  
Lei Zhao ◽  
Ling-Yu Zhou ◽  
Guang-Chao Zhang ◽  
Tian-Yu Wei ◽  
Akim D. Mahunon ◽  
...  

To study the temperature distribution in the China Railway Track System Type II ballastless slab track on a high-speed railway (HSR) bridge, a 1:4 scaled specimen of a simply-supported concrete box girder bridge with a ballastless track was constructed in laboratory. Through a rapid, extreme high temperature test in winter and a conventional high temperature test in summer, the temperature distribution laws in the track on the HSR bridge were studied, and the vertical and transverse temperature distribution trend was suggested for the track. Firstly, the extreme high temperature test results showed that the vertical temperature and the vertical temperature difference distribution in the track on HSR bridge were all nonlinear with three stages. Secondly, the extreme high temperature test showed that the transverse temperature distribution in the track was of quadratic parabolic nonlinear form, and the transverse temperature gradient in the bottom base was significantly higher than that of the other layers of the track. Thirdly, the three-dimensional temperature distribution in the track on HSR bridge was a nonlinear, three-stage surface. Furthermore, similar regularities were also obtained in the conventional high temperature test, in which the temperature span ranges were different from those of the extreme high temperature test. In addition, the conventional high temperature test also showed that under the natural environment conditions, the internal temperature gradient in the track layers changed periodically (over a period of 24 h).


2018 ◽  
Vol 165 ◽  
pp. 22-33 ◽  
Author(s):  
Jinhui Wang ◽  
Yu Jiao ◽  
Long Shi ◽  
Qimiao Xie ◽  
Guoqiang Li ◽  
...  

During the past four years a considerable number of small free balloons carrying selfrecording instruments have been sent up in the British Isles, and sufficient observations have now accumulated to give some idea of the conditions which prevail over England, to a height of about 10 miles, in summer and winter, in cyclonic and anticyclonic weather. The method of obtaining observations is fully described in a publication of the Meteorological Office, M.O. 202. It will suffice here to state that a small selfrecording instrument, weighing 1 oz. (35 gr.), is attached by about 30 ft. (9 metres) of strong thread to a small rubber balloon. The balloon is 1 ft. diameter when unstretched. It is filled with hydrogen until it is expanded to about 1 m. diameter, securely tied up, and then let go. The balloons generally rise until they burst, and carry the instrument on the average to a height of 10 miles (16 km). A label offering a reward of 5 s . is attached to the instrument, and the reward is claimed and the instrument returned in two cases out of three.


2021 ◽  
pp. 002029402110071
Author(s):  
Da Wang ◽  
Benkun Tan ◽  
Xie Wang ◽  
Zhenhao Zhang

The temperature distribution of the bridge and its thermal effect has always been an important issue for researchers. To investigate the temperature distribution and thermal stress in the steel-concrete composite bridge deck, a 1:4 ratio temperature gradient effect experimental study was carried out in this paper. First, a set of experimental equipment for laboratory temperature gradient loading was designed based on the principle of temperature gradient caused by solar radiation, the temperature gradient obtained from the measurements were compared with the specifications and verified by the FE method. Next, the loading of the steel-concrete composite deck at different temperatures was performed. The thermal stress response and change trend of the simply supported and continuously constrained boundary conditions under different temperature loads were analyzed. The experimental results show that the vertical temperature of steel-concrete composite bridge deck is nonlinear, which is consistent with the temperature gradient trend of specifications. The vertical temperature gradient has a great influence on the steel-concrete composite bridge deck under different constraints, and the extreme stress of concrete slab and steel beam is almost linear with the temperature gradient. Finally, some suggestions for steel-concrete composite deck design were provided based on the research results.


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