scholarly journals Modern methods of cooling permafrost ground beds of multi-storey residential buildings

Vestnik MGSU ◽  
2021 ◽  
pp. 535-544
Author(s):  
Аleksandr А. Plotnikov ◽  
Georgy R. Guryanov

Abstract Introduction. The bearing capacity of soil in the frozen state is much higher than its bearing capacity at positive temperatures. Therefore, it makes sense to use frozen soil as the footing of a building in permafrost regions. However, the preservation of soil in the frozen state in a built-up area is a challenging engineering problem despite low average annual air temperatures (below –4 °C). Materials and methods. The co-authors employed numerical methods to study the temperature regime of the footing using TEMRA software. This software was developed at MISI – MGSU (State Registration Certificate 2016618937); it solves non-stationary thermophysical problems by the enthalpy method with regard for the phase transitions of the bound moisture in the temperature range. Results. Two approaches are used to preserve building footings in the frozen state: natural seasonal surface cooling and deep cooling, on the one hand, and reducing the thermal effect produced by the building on footing soils, on the other hand. In the first case, the surface under the building is cooled with air in the winter season using the cold ventilated space under the building, the so-called “ventilated basement”. Deep cooling is carried out using Seasonal Cooling Devices (SCD) that employs air-soil heat exchange with the help of pipes, filled with the heat transfer agent during the winter period. A change in the average annual air temperature inside the ventilated basement and seasonal insulation of its walls or the ground bed can reduce the thermal effect, produced by the building. Conclusions. The most effective way to keep ground beds of multi-storey residential buildings frozen is the thermal insulation of the footing surface in combination with deep liquid cooling devices.

1986 ◽  
Vol 17 (4-5) ◽  
pp. 399-406
Author(s):  
Arve M. Tvede

The reservoir Sundsbarmvatn, in Southern Norway, is used for electricity production from November to May. Sundsbarmvatn has two main basins. Water from the upper basin, Mannerosfjorden, flows into the lower basin, Gullnesfjorden. The two basins are separated by a narrow sound with a sill. The regulation interval for Sundsbarmvatn is 612-574 m a.s.l., but the sill prevents Mannerosfjorden from being lowered below 580 m a.s.l. The water intake in Gullnesfjorden is 571 m a.s.l. The water temperature conditions has been studied during two winters when the reservoir water was released. This study shows that a marked thermocline was gradually developed at the depth of withdrawal in Gullnesfjorden. In the epilimnion layer the temperature is gradually lowered through the winter, but in the hypolimnion layer the temperature seems to stay constant through the winter. In Mannerosfjorden, however, we find no clear thermocline at the end of the winter. The remaining water was relatively warm with temperatures mainly above 3 °C. The sill between the two basins seems to have a strong influence on which depth the water is flowing out of Mannerosfjorden and hence on the temperature and circulation pattern in Gullnesfjorden. At the end of the winter season this flow is strengthening and initiates a homogeneous flow layer in Gullnesfjorden. This layer is dipping downwards towards the outlet tunnel. For this reason the temperature of the water leaving the power station is 0.4-1.2 °C colder than the hypolimnion temperature in the reservoir at the tunnel depth.


2019 ◽  
Vol 23 (3) ◽  
pp. 1611-1631 ◽  
Author(s):  
Ilari Lehtonen ◽  
Ari Venäläinen ◽  
Matti Kämäräinen ◽  
Antti Asikainen ◽  
Juha Laitila ◽  
...  

Abstract. Trafficability in forest terrain is controlled by ground-bearing capacity, which is crucial from the timber harvesting point of view. In winter, soil frost affects the most the bearing capacity, especially on peatland soils which have in general low bearing capacity. Ground frost similarly affects the bearing capacity of forest truck roads. A 20 cm thick layer of frozen soil or 40 cm thick layer of snow on the ground may already be sufficient for heavy forest harvesters. In this work, we studied the impacts of climate change on soil frost conditions and, consequently, on ground-bearing capacity from the timber harvesting point of view. The number of days with good wintertime bearing capacity was modelled by using a soil temperature model with a snow accumulation model and wide set of downscaled climate model data until the end of the 21st century. The model was calibrated for different forest and soil types. The results show that by the mid-21st century, the conditions with good bearing capacity will decrease in wintertime in Finland, most likely by about 1 month. The decrease in soil frost and wintertime bearing capacity will be more pronounced during the latter half of the century, when drained peatlands may virtually lack soil frost in most of winters in southern and western Finland. The projected decrease in the bearing capacity, accompanied with increasing demand for wood harvesting from drained peatlands, induces a clear need for the development of sustainable and resource-efficient logging practices for drained peatlands. This is also needed to avoid unnecessary harvesting damages, like rut formation on soils and damage to tree roots and stems.


Author(s):  
Oleksandr Horbach

The analysis of monthly climatic terms of Rivnenskyi Nature Reserve was conducted. It is marked that weather terms have substantial differences due to an unstable temperature condition since creation of reserve. A spring period was the shortest in 2013 – 64 days and had the greatest average daily temperature 11.9 °С. Protracted a spring period was in 2002 – 123 days. The most of precipitations in a spring period was fixed in 2008 – 196.2 mm, and the least in 2011 – 42.1 mm. A summer period in 2015 became the most protracted – 131 day. Moreover, the least protracted summer was in 2006 – 90 days. The warmest summer season was in 2010 with an average daily temperature 19.8 °С. The most raining summer was in 2007 when a 471.3 mm of precipitations is fixed, and the least raining summer was in 2002 (144.6 mm of precipitations). The most protracted autumn period was in 2006 – 107 days and the shortest one was in 2001 – 57 days. The warmest autumn was in 2004 when an average daily temperature reached 9.2°С. The most of precipitations in the autumn period is fixed in 2009 – 178 mm, and the least in 2001 – 39 mm. The winter periods were protracted in 2004/05 and 2005/06. Their duration was 114 days. Winter period in 2009/10 with an average daily temperature -7.9°С was the coldest one. The most precipitations are fixed in winter 2005/06 – 208.4 mm, and the least in a winter period 2012/13 are a 52.2 mm. The most of precipitations for a year fell out 777.8 mm in 2012, and the least one in 2011 – 427 mm. The average long-term dates of the beginning of the year seasons are defined. The average long-term date of the beginning of the spring season is on February 27; the summer season is on May 26; the autumn season is on September 14; the winter season is on December 5. Key words: Rivnenskyi Nature Reserve, seasons of the year, precipitation, climatic terms, temperature, long-term date.


2019 ◽  
Vol 63 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Asli Özkırım ◽  
Aygün Schiesser ◽  
Nevіn Keskin

AbstractNosema apis is a pathogen spesific for the European honeybee, Apis mellifera L., while Nosema ceranae is specific for the Asian honeybee, Apis cerana. Turkey provides different environmental and host conditions for both Nosema species. The aim of the study is to determine the dynamic of N. cerenae and N. apis seasonal infection. A number of samples were collected from different apiaries between 2009-2016 years. The samples were kept at −20°C in the laboratory. Light microscopy was used for spore counting and molecular techniques were used to identify the Nosema species. The results showed that winter season had an impact on the type of Nosema as well as on infection rates. The number of N. ceranae spores decreases significantly at low temperatures (≤ 5°C). The winter period was found to be the main factor affecting nosema infection level and dominancy of Nosema ceranae. Furthermore, co-infection of both species is an indicator of the dynamics of N. apis and N. ceranae. This study suggests, that there is a dynamic prevalence among the Nosema species depending of the average winter temperature and not a replacement of N. apis by N. ceranae.


2021 ◽  
Vol 23 (103) ◽  
pp. 56-59
Author(s):  
S. B. Abbasov

The article refers to the research work carried out in recent years at the poultry farms of the Khachmaz region of the Republic of Azerbaijan, the influence of opportunistic microbes on the activities of the farm. The role of opportunistic microbes in the occurrence of certain diseases with deficiencies in the process of feeding and raising of birds, and the microclimate in poultry farms is shown. During the bacteriological examination of breeding eggs by seasons there were revealed the presence of infection in the winter season with E. coli, Salmonella, Staphylococcus and Streptococcus – with each infection separately 13.0 %, in the spring season with E. coli, Salmonella, Staphylococcus – with each infection separately 20.0 %, in the autumn period with E. coli 27.0%, Salmonella 40.0 %, Staphylococcus 13.0 % and Streptococcus 13.0 %. In the course of bacteriological examination of dead embryos, the presence of infection in the winter period with E. coli 20.0 %, salmonella 30.0 %, staphylococcus 25.0 % and streptococcus 25.0 %, in the spring  season with E. coli 30.0 %, salmonella 40.0 %, staphylococcus 15.0 % and streptococcus 15.0 %, in the autumn season with E. coli 45.0 %, salmonella 55.0 % was revealed. In the autumn period, infection with staphylococci and streptococci was not detected. When studying as a whole, pseudomoniasis and mold fungi were not found.


2007 ◽  
Vol 1 (2) ◽  
pp. 303-350 ◽  
Author(s):  
U. Strasser ◽  
M. Bernhardt ◽  
M. Weber ◽  
G. E. Liston ◽  
W. Mauser

Abstract. In alpine terrain, snow sublimation as a component of the winter moisture budget represents a proportion of precipitation which does not contribute to melt. To quantify its amount we analyze the spatial pattern of snow sublimation at the ground, from a canopy and from turbulent suspension during wind-induced snow transport for a high alpine area in the Berchtesgaden National Park (Germany), and we discuss the efficiency of these processes with respect to seasonal snowfall. Therefore, we utilized hourly meteorological recordings from a network of automatic stations, and a distributed simulation framework comprising validated, physically based models. Meteorological data records were spatially distributed over the simulation domain by means of a quasi-physically based interpolation scheme that accounts for topographic influences on the distributed fields. The applied simulation tools were: a detailed model for shortwave and longwave radiative fluxes, a mass and energy balance model for the ground snow cover, a model for the microclimatic conditions within a forest canopy and related snow-vegetation interactions including snow sublimation from the surface of the trees, and a model for the simulation of wind-induced snow transport and related sublimation from suspended snow particles. For each of the sublimation processes, mass rates were quantified and aggregated over an entire winter season. Sublimation from the ground and from most canopy types are spatially relatively homogeneous and sum up to about 100 mm of snow water equivalent (SWE) over the winter period. Accumulated seasonal sublimation due to turbulent suspension is small in the valley areas, but can locally, at very wind-exposed mountain ridges, add up to more than 1000 mm of SWE. The fraction of these sublimation losses of winter snowfall is between 10 and 90%.


2021 ◽  
pp. 136943322110463
Author(s):  
Tiegang Zhou ◽  
Xin Wang ◽  
Ben Ma ◽  
Zaiyu Zhang ◽  
Wei Tan

At present, adobe houses with traditional characteristics are still widely used in rural areas in western China, but their seismic performance is relatively poor, and they often suffer serious damage under earthquake. To improve the seismic performance of traditional adobe buildings while retaining the characteristics of residential buildings, the mechanical properties of compressed earth blocks (CEB) were tested in this study, and the microstructure characteristics of CEB after failure were analyzed by electron microscope. On this basis, six adobe wall specimens were designed and tested by quasi-static loading to investigate the influence of core columns and different types of bricks on its seismic performance. The results show that the core column can improve the bearing capacity and shear capacity of hollow CEB, and it can also significantly increase the bearing capacity, energy dissipation capacity, and ductility of CEB wall. In general, the adobe wall with core columns shows excellent seismic performance, which can provide a new choice for improving the seismic performance of the adobe house.


2019 ◽  
Vol 265 ◽  
pp. 02019
Author(s):  
Sergei Kudriavtcev ◽  
Viacheslav Kovshun

Weak thawing soils around the metal piles pose the main danger when constructing oil pipelines or other engineering structures located in the cryolithozone. The occurrence of ice inside soil causes thermokarst dips and settlement while thawing. High-precision calculations of the load-bearing capacity of soils and accurate forecasts of the amount of thawing in summer are necessary for improving the reliability of engineering structures. Thermopiles are used to prevent thawing of soils around piles and thermally stabilize the permafrost condition. In this article, one of such decisions is considered on the example of oil pipeline along «Kuyumba – Taishet Kozmino» route in Russia. There are permafrost and deformations of the soil body in the base of oil pipeline. The proposed method implies the joint operation of holding soils in frozen state with help of season-cooling devices or thermopiles. It was concluded that special geotechnical engineering for permafrost projects is necessary to avoid the main problems. In order to achieve the goals of the present investigation, the geotechnical software complex «FEM-models» with «Termoground» was used.


2008 ◽  
Vol 12 (1) ◽  
pp. 91-100 ◽  
Author(s):  
D. Vanham ◽  
E. Fleischhacker ◽  
W. Rauch

Abstract. Alpine regions are particularly affected by seasonal variations in water demand and water availability. Especially the winter period is critical from an operational point of view, as being characterised by high water demands due to tourism and low water availability due to the temporal storage of precipitation as snow and ice. The clear definition of summer and winter periods is thus an essential prerequisite for water resource management in alpine regions. This paper presents a GIS-based multi criteria method to determine the winter season. A snow cover duration dataset serves as basis for this analysis. Different water demand stakeholders, the alpine hydrology and the present day water supply infrastructure are taken into account. Technical snow-making and (winter) tourism were identified as the two major seasonal water demand stakeholders in the study area, which is the Kitzbueheler region in the Austrian Alps. Based upon different geographical datasets winter was defined as the period from December to March, and summer as the period from April to November. By determining potential regional water balance deficits or surpluses in the present day situation and in future, important management decisions such as water storage and allocation can be made and transposed to the local level.


2019 ◽  
Vol 7 (6) ◽  
pp. 182
Author(s):  
Francesco Ragone ◽  
Andrea Meli ◽  
Anna Napoli ◽  
Claudia Pasquero

The Western Mediterranean Sea is often subject to intense winds, especially during the winter season. Intense winds induce surface cooling associated with anomalous ocean heat loss, upwelling and diapycnal mixing. In this study we investigate the overall impact of extreme wind events on the upper ocean in the Western Mediterranean sea using sea surface temperature and sea surface height observational data products over the period 1993–2014. We show that the largest thermal anomaly is observed a couple of days after the intense wind event and that it is dependent on the wind intensity. During winter, when deep water formation occurs, it persists for over a month. During summer, when the thermocline is very shallow, the recovery time scale is typically less than 10 days. The sea surface height signal reaches a minimum in correspondence to the intense wind, and normal conditions recover in about six weeks. Unlike for intense winds in the tropics associated to the passage of tropical cyclones, no long term sea surface height anomaly is observed, indicating that the water column heat content is not significantly modified. The observed recovery times suggest instead the possibility of feedbacks on the dynamics of intense cyclones at sub-monthly time scales.


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