scholarly journals Characteristics of ground freezing and thawing under snow cover based on long-term observation

2009 ◽  
Vol 71 (4) ◽  
pp. 241-251
Author(s):  
Yusuke HARADA ◽  
Fujio TSUCHIYA ◽  
Kazuo TAKEDA ◽  
Toshimi MUNEOKA
Keyword(s):  
Snow Cover ◽  
Freezing And Thawing ◽  
Ground Freezing ◽  
Long Term Observation

Geothermal modeling of soil or mine tailings with concurrent freezing and deposition

1998 ◽  
Vol 35 (2) ◽  
pp. 234-250 ◽  
Author(s):  
JF (Derick) Nixon ◽  
Nick Holl
Keyword(s):  
Snow Cover ◽  
Mine Tailings ◽  
Frozen Soil ◽  
Freezing And Thawing ◽  
Frozen Ground ◽  
Geothermal Model ◽  
Winter Time ◽  
Upper Boundary ◽  
Good Agreement

A geothermal model is described that simulates simultaneous deposition, freezing, and thawing of mine tailings or sequentially placed layers of embankment soil. When layers of soil or mine tailings are placed during winter subfreezing conditions, frozen layers are formed in the soil profile that may persist with time. The following summer, warmer soil placement may not be sufficient to thaw out layers from the preceding winter. Remnant frozen soil layers may persist for many years or decades. The analysis is unique, as it involves a moving upper boundary and different surface snow cover functions applied in winter time. The model is calibrated based on two uranium mines in northern Saskatchewan. The Rabbit Lake scenario involves tailings growth to a height of 120 m over a period of 24 years. At Key Lake, tailings increase in height at a rate of 1.3 m/year. Good agreement between the observed position of frozen layers and those predicted by the model is obtained. Long-term predictions indicate that from 80 to 200 years would be required to thaw out the frozen layers formed during placement, assuming 1992 placement conditions continue. Deposition rates of 1.5-3 m/year give the largest amounts of frozen ground. The amount of frozen ground is sensitive to the assumed snow cover function during winter.Key words: geothermal, model, tailings, freezing, deposition.

scholarly journals Calculation scheme of ground freezing depth in Terskol

2021 ◽  
Vol 135 (2) ◽  
pp. 7-13
Author(s):  
D.M. Frolov ◽  
Keyword(s):  
Phase Transition ◽  
Snow Cover ◽  
Calculation Scheme ◽  
Frozen Ground ◽  
Ground Freezing ◽  
Geotechnical Structures ◽  
Freezing Depth ◽  
Layer Medium ◽  
The Heat Balance

During the construction of avalanche-retaining geotechnical structures in mountainous areas comes up the problem of fixing and stability of these structures in conditions of seasonal and/or long-term freezing of the ground. This paper evaluates the influence of snow cover and air temperature on the depth of freezing and soil stability based on the developed calculation scheme for the winter seasons 2015/16-2019/20 in the Elbrus region. The calculation scheme was based on the problem of thermal conductivity of a three-layer medium (snow, frozen, and thawed soil) with a phase transition at the boundary. The heat balance equation included the energy of the phase transition, the inflow of heat from the thawed ground and the outflow to the frozen ground, and, in the presence of snow cover, through it to the atmosphere.

scholarly journals Peculiarities of weather and snow accumulation conditions in Moscow region in winter period 2019/2020

2020 ◽  
Vol 164 ◽  
pp. 01018 ◽  
Author(s):  
Denis Frolov
Keyword(s):  
Snow Cover ◽  
Temperature Regime ◽  
Snow Accumulation ◽  
Moscow Region ◽  
Winter Period ◽  
Ground Freezing ◽  
Freezing Depth

The study of weather and snow accumulation conditions is important because for example on basis of knowledge on temperature regime and accumulation peculiarities of snow cover the ground freezing depth calculations are performed. So the results of study of peculiarities of weather and snow accumulation conditions in Moscow region for winter period 2019/2020 are presented in the paper. The comparison of these data for this winter period with the previous winter periods and the long-term averaged values is also done.

scholarly journals SAT0137 Long-term observation of fibromyalgia patients

2001 ◽  
Author(s):  
L Szczepanski ◽  
C Stepniak ◽  
B Targonska-Stepniak
Keyword(s):  
Long Term Observation

scholarly journals Phenotype of the Aging-Dependent Spontaneous Onset of Hearing Loss in DBA/2 Mice

2021 ◽  
Vol 8 (3) ◽  
pp. 49
Author(s):  
Min-Soo Seo ◽  
Byeonghyeon Lee ◽  
Kyung-Ku Kang ◽  
Soo-Eun Sung ◽  
Joo-Hee Choi ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Early Stage ◽  
Auditory Brainstem ◽  
Dependent Manner ◽  
Intrinsic Properties ◽  
Hearing Ability ◽  
Brainstem Response ◽  
Long Term Observation ◽  
Spontaneous Onset

DBA/2 mice are a well-known animal model for hearing loss developed due to intrinsic properties of these animals. However, results on the phenotype of hearing loss in DBA/2 mice have been mainly reported at an early stage in mice aged ≤7 weeks. Instead, the present study evaluated the hearing ability at 5, 13, and 34 weeks of age using DBA/2korl mice. Auditory brainstem response test was performed at 8–32 KHz at 5, 13, and 34 weeks of age, and hearing loss was confirmed to be induced in a time-dependent manner. In addition, histopathological evaluation at the same age confirmed the morphological damage of the cochlea. The findings presented herein are the results of the long-term observation of the phenotype of hearing loss in DBA/2 mice and can be useful in studies related to aging-dependent hearing loss.

scholarly journals Posterior Uveal Effusion after Cataract Surgery

2021 ◽  
pp. 62-67
Author(s):  
Annegret Abaza ◽  
Özlem Dikmetas ◽  
Irmingard Neuhann ◽  
Faik Gelisken
Keyword(s):  
Cataract Surgery ◽  
Corticosteroid Therapy ◽  
Anterior Segment ◽  
Subretinal Fluid ◽  
Posterior Pole ◽  
Functional Improvement ◽  
Long Term Observation ◽  
The Right ◽  
Uveal Effusion

We report a case of posterior uveal effusion (UE) with a long-term follow-up that has occurred following cataract surgery. A 64-year-old woman presented with diminished vision of the right eye (RE) 3 weeks after an uneventful phacoemulsification and intraocular lens implantation. Complete ophthalmic examination including fluorescein angiography (FA), indocyanine green angiography (ICGA), echography and optical coherence tomography (OCT) were performed. Best corrected visual acuity (BCVA) of the RE was 20/50. Anterior segment and intraocular pressure were unremarkable. OCT revealed prominent folds of the choroid and retina, subretinal fluid and darkening of the choroid with reduced visibility of the choroidal vessels and the scleral border. The left eye (LE) was unremarkable. BCVA of the LE was: 20/20. After topical anti-inflammatory and systemic corticosteroid therapy for 5 months, no morphological change of the macula was seen. The patient was observed without any treatment. Forty-three months after the cataract surgery and 38 months after cessation of the corticosteroid therapy, OCT revealed a normal macular morphology and the BCVA improved to 20/25. Even though rare, UE at the posterior pole may occur after modern cataract surgery. OCT examination is a reliable tool in monitoring the macular morphology. Since morphological and functional improvement can be seen in long-term, observation may be considered for some cases of posterior UE with resistance to the therapy.

scholarly journals Atmospheric Thermal and Dynamic Vertical Structures of Summer Hourly Precipitation in Jiulong of the Tibetan Plateau

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 505
Author(s):  
Yonglan Tang ◽  
Guirong Xu ◽  
Rong Wan ◽  
Xiaofang Wang ◽  
Junchao Wang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tibetan Plateau ◽  
Precipitation Amount ◽  
Summer Precipitation ◽  
The Tibetan Plateau ◽  
Hourly Precipitation ◽  
Air Convection ◽  
Precipitation Variation ◽  
Long Term Observation

It is an important to study atmospheric thermal and dynamic vertical structures over the Tibetan Plateau (TP) and their impact on precipitation by using long-term observation at representative stations. This study exhibits the observational facts of summer precipitation variation on subdiurnal scale and its atmospheric thermal and dynamic vertical structures over the TP with hourly precipitation and intensive soundings in Jiulong during 2013–2020. It is found that precipitation amount and frequency are low in the daytime and high in the nighttime, and hourly precipitation greater than 1 mm mostly occurs at nighttime. Weak precipitation during the daytime may be caused by air advection, and strong precipitation at nighttime may be closely related with air convection. Both humidity and wind speed profiles show obvious fluctuation when precipitation occurs, and the greater the precipitation intensity, the larger the fluctuation. Moreover, the fluctuation of wind speed is small in the morning, large at noon and largest at night, presenting a similar diurnal cycle to that of convective activity over the TP, which is conductive to nighttime precipitation. Additionally, the inverse layer is accompanied by the inverse humidity layer, and wind speed presents multi-peaks distribution in its vertical structure. Both of these are closely related with the underlying surface and topography of Jiulong. More studies on physical mechanism and numerical simulation are necessary for better understanding the atmospheric phenomenon over the TP.

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