scholarly journals Variation of Ground Temperature along the Stratum Depth in Ice-rich Tundra

2020 ◽  
Author(s):  
Ziying Liu ◽  
Tianlai Yu ◽  
Ning Yan ◽  
Lipeng Gu
Keyword(s):  
Pile Foundation ◽  
Concrete Strength ◽  
Negative Temperature ◽  
Ground Temperature ◽  
Permafrost Region ◽  
Depth Range ◽  
Actual Measurement ◽  
Temperature Environment ◽  
Different Depths ◽  
The Law

The pile foundation in the permafrost region is in a negative temperature environment, so the concrete is affected by the negative temperature of the surrounding soil.It not only affects the formation of concrete strength, but also leads to engineering quality accidents in serious cases.Based on the actual measurement of temperature at different strata depths and the comprehensive consideration of surface temperature, terrestrial heat flux and other parameters, the law curve of temperature change along depth in Greater Khingan is established.The calculated results of the curve are consistent with the measured results of ground temperature.The results show that the variation trend of ground temperature along the strata depth at different monitoring sites is basically the same. From June to November, the ground temperature at different depths tends to be constant.From December to May, the ground temperature at any depth within the depth range of 0 to 5.5m follows the law of the cosine function.Below 5.5m, the earth temperature no longer varies with depth.The research results can be used as reference for pile foundation construction under negative temperature environment.

scholarly journals Variation of Ground Temperature along the Stratum Depth in Ice-rich Tundra of Hinggan Mountains Region, NE China

Geosciences ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 104
Author(s):  
Ziying Liu ◽  
Tianlai Yu ◽  
Ning Yan ◽  
Lipeng Gu
Keyword(s):  
Temperature Profile ◽  
Pile Foundation ◽  
Negative Temperature ◽  
Ground Temperature ◽  
Dynamic Monitoring ◽  
Theoretical Ground ◽  
Permafrost Region ◽  
Monitoring Method ◽  
Actual Measurement ◽  
Temperature Environment

A pile foundation in a permafrost region is in a negative-temperature environment, so concrete is affected by the negative temperature of the surrounding soil. It not only affects the formation of concrete strength but also leads to engineering quality accidents in serious cases. With the support of the two permafrost bridge projects of the national highway from Beijing to Mohe in the Greater Khingan Mountains region, a systematic remote dynamic monitoring method for ground temperature in ice-rich tundra is proposed. Based on the actual measurement of temperature at different strata depths and the comprehensive consideration of surface temperature, terrestrial heat flux and other parameters, the ground temperature profile evolution in relation to depth in Greater Khingan was established. The theoretical ground temperature profile curve is similar to the measured profile. The results show that the variation trends of ground temperatures in relation to the strata depth at different monitoring sites is similar, and all show seasonal variation: From June to November, the ground temperature at different depths tends to be constant. From December to May, the ground temperature at any depth within the range of 0 to 5.5 m follows the curve of the cosine function. Below 5.5 m, the earth temperature no longer varies with depth. The research results can be used as reference for pile foundation construction in a negative-temperature environment in ice-rich tundra.

scholarly journals ANALYSIS OF ACOUSTIC ANISOTROPY PARAMETERS OF PYROXENE-MAGNETITE ROCKS OF THE PISCHANKA STRUCTURE

2020 ◽  
pp. 40-45
Author(s):  
I. Bezrodna ◽  
V. Svystov ◽  
D. Bezrodny
Keyword(s):  
Acoustic Properties ◽  
Significant Heterogeneity ◽  
Depth Range ◽  
Transverse Waves ◽  
Acoustic Anisotropy ◽  
Micro Cracks ◽  
Acoustic Tensor ◽  
Transverse Isotropic ◽  
Different Depths ◽  
The Difference

The analysis of the results of acoustic properties of rocks study of Pischans`ka iron-ore structure is presented. The aim of the work is to establish the features of the distribution of acoustic properties and parameters of acoustic anisotropy in samples of core rocks selected from the well No. 3 of the Pischans`ka structure to determine the nature of its occurrence. A sample of 35 samples from the depth range 144-273 m is divided into 3 groups of rocks, namely: magnetite-pyroxene, quartz-magnetitepyroxene and biotite-amphibole crystalline shales. Based on an invariant polarization method, a number of acoustic laboratory measurements have been carried out. The values of the measured phase velocities "quasi-longitudinal" and two "quasi-transverse" waves at the stage of measurements showed significant acoustic anisotropy of the rocks. The ranges of the measured speeds of the collection samples are 7661 ÷ 5046 m / s for longitudinal waves and 4232 ÷ 2648 m/s for transverse ones. The difference in values measured for each of the sides of the cubic rhombic dodecahedron is from 100 to 800 m / s and from 0 to 500 m/s for Vp and Vs, respectively. The parameters of an acoustic ellipsoid were calculated, on the basis of which the division of samples into 3 main groups has been performed, according to the acoustic texture: acoustically linear, shale and rhombic. Separately, a group of samples with a more complex texture was discovered. The analysis of coefficients of anisotropy by different methods is carried out: longitudinal, transverse and relative acoustic anisotropy. Most of the samples are characterized by low or average acoustic anisotropy (from 2 to 7 %). A group of highly anisotropic rocks (11–14 %), represented by samples of biotite-amphibole crystalline silicates, is singled out. According to the parameters of the acoustic tensor of most samples, the transverse isotropic type of symmetry inherent to samples from the depth intervals 174–220 m and 222–232 m, while the smaller part is rhombic, is inherent. Differences in the parameters of anisotropy of samples can be explained by the significant heterogeneity of their textures, namely: micro cracks, minerals of various sizes, shapes and orientations. The results of the research show that the acoustic properties of the samples are quite heterogeneously distributed along the investigated depth range. This indicates the difficult conditions for the formation of rocks at different depths and the presence of different types of deformations, which accompanied the formation of the Pischans`ka structure.

scholarly journals Influence of Lawns on the Summer Thermal Environment and Microclimate of Heritage Sites: A Case Study of Fuling Mausoleum, China

2020 ◽  
Author(s):  
Xiaoyu Wang ◽  
Peng Liu ◽  
Gongwen Xu
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Thermal Environment ◽  
Measurement Data ◽  
Ground Temperature ◽  
Rapid Urbanization ◽  
Actual Measurement ◽  
Heritage Sites ◽  
Human Thermal Comfort ◽  
The Impact

Abstract The thermal environment and microclimate of heritage sites has been severely impacted by rapid urbanization. This study collected various meteorological measurement data as a reference for computational fluid dynamics (CFD) simulation settings. Then CFD was applied to simulate the impact of lawns on the thermal environment and microclimate of Fuling Mausoleum. We found that lawns and soil can cool the air through evaporation, and thus have a specific cooling effect on the bricked ground. After lawns were planted, the bricked ground temperature decreased by 1.56–17.54°C than that before lawns were planted at 14:00, a decrease of 2.68%–24.20%. Under normal circumstances, when the wind speed or relative humidity increased, the ground temperature dropped. Greenbelt vegetation can adjust the microclimate and human thermal comfort indicators. The consistency of the difference between the actual measurement and the CFD simulation results shows that CFD simulation can thus accurately reflect the internal temperature field distribution if the selection of simulation parameters is reasonable. Theoretical calculation and analysis, experimental measurement research, and modern computer simulation analysis methods applied together constitute a complete system for studying modern physical environmental problems and can provide reliable and economic results.

scholarly journals Field measurement of ground temperatures in Bandung: devices and the results of measurement

2020 ◽  
Vol 200 ◽  
pp. 02009
Author(s):  
Muhammad Nur Fajri Alfata ◽  
Amalia Nurjannah
Keyword(s):  
Temperature Sensor ◽  
Field Measurement ◽  
Ground Temperature ◽  
Passive Cooling ◽  
Temperature Profiles ◽  
Temperature Changes ◽  
Ground Temperatures ◽  
Different Depths ◽  
Measurement Devices ◽  
Main Component

Ground cooling is considered to be one of the passive cooling strategies in buildings although its application is rarely found in Indonesia. Effectiveness of this strategy depend on the ground temperature profiles. Meanwhile, comprehensive data of ground temperature as a basis of design for ground cooling are still rarely found in Indonesia. This research aims to develop the measurement devices for collecting ground temperatures data and to investigate the ground temperatures in different depths (i.e., 1m, 2m, …, 9m). For measurement, an instrumentation system was developed with the main component of Arduino Mega 2560 as microcontroller. T-type thermocouples with diameter of 0, 5mm mounted in the metal cones were used as the temperature sensor and placed at the different depths. The field measurement was conducted from August to November 2019 in Bandung, West Java, Indonesia. This study demonstrated that the developed instrument system had good performance both in measuring and data acquisition. Model equation was developed to predict the ground temperature at certain depth regardless ground materials and humidity level. The results indicated that the ground temperature significantly lower to 5m-depth. However, the reduction of the temperature after 5m was not significant; the deeper the ground, the temperature changes are negligible.

scholarly journals A photoacoustic imaging system with variable gain at different depths

2018 ◽  
Vol 11 (05) ◽  
pp. 1850022 ◽  
Author(s):  
Tian Guan ◽  
Yao Li ◽  
Muqun Yang ◽  
Yong Jiang ◽  
Yonghong He
Keyword(s):  
Nude Mice ◽  
Photoacoustic Imaging ◽  
The Body ◽  
Chicken Breast ◽  
Processing Unit ◽  
Depth Range ◽  
Variable Gain ◽  
Imaging Results ◽  
Different Depths ◽  
Imaging Depth

We established a photoacoustic imaging (PAI) system that can provide variable gain at different depths. The PAI system consists of a pulsed laser with an optical parametric oscillator working at a 728[Formula: see text]nm wavelength and an imaging-acquisition-and-processing unit with an ultrasound transducer. A voltage-controlled attenuator was used to realize variable gain at different depths when acquiring PAI signals. The proof-of-concept imaging results for variable gain at different depths were achieved using specific phantoms. Both resolution and optical contrast obtained through the results of variable gain for a targeted depth range are better than those of constant gain for all depths. To further testify the function, we imaged the sagittal section of the body of in vivo nude mice. In addition, we imaged an absorption sample embedded in a chicken breast tissue, reaching a maximum imaging depth of [Formula: see text]4.6[Formula: see text]cm. The results obtained using the proposed method showed better resolution and contrast than when using 50[Formula: see text]dB gain for all depths. The depth range resolution was [Formula: see text]1[Formula: see text]mm, and the maximum imaging depth of our system reached [Formula: see text]4.6[Formula: see text]cm. Furthermore, blood vessels can be revealed and targeted depth range can be selected in nude mice imaging.

Dynamic Behavior of Pile Foundation in Frozen and Thawing Soil

2011 ◽  
Vol 105-107 ◽  
pp. 1391-1399
Author(s):  
Hao Li ◽  
Wei Nan Lu
Keyword(s):  
Pile Foundation ◽  
Dynamic Stiffness ◽  
Soil Layer ◽  
Tibet Plateau ◽  
Triaxial Tests ◽  
Permafrost Region ◽  
Harmonic Load ◽  
Stiffness And Damping ◽  
Qinghai Tibet Plateau ◽  
Temperature Dynamic

Permafrost is widespread in China, especially in Northeast China and the Qinghai-Tibet Plateau. Regions like Qinghai-Tibet Plateau have the most strenuous crustal movement. Therefore, earthquake-resistance of structures in permafrost region is an important issue. Furthermore, the permafrost will degenerate gradually as global warming mounts up. In some regions permafrost thickness tends to attenuate. Most bridge designs adopt pile foundation in order to reduce the effects of instable frost. The deterioration of frost leads to degradation of anti-seismic performance of bridges’ pile foundations. Pile-soil dynamic interaction numerical analysis models are established based on data of indoor low-temperature dynamic triaxial tests. Studies are performed on the dynamic stiffness and damping characters and the influencing factors of pile foundation under vertical harmonic load in frozen and thawing soil. The result shows that the dynamic response of the pile decreases along the depth, and the frictional resistance around the pile mainly distributes along the upper half of the pile, and the dynamic stiffness and damping of the pile are affected by temperature. Dynamic stiffness increases as temperature goes down, whereas the decrease of the temperature of frozen soil can notably lower the dynamic damping of the head of the pile. As the frequency of the dynamic load augments, the dynamic stiffness of the head increases marginally, whereas frequency has little influence on damping. The relative thickness of the frozen and thawing soil layer has considerable influence on dynamic stiffness, but negligible on damping.

XVIII. On the measurement of Snowdon, by the thermometrical barometer

1820 ◽  
Vol 110 ◽  
pp. 295-305
Keyword(s):  
Royal Society ◽  
Elastic Force ◽  
Boiling Temperature ◽  
Actual Measurement ◽  
The Law

The Royal Society did me the honour to notice in their Transactions, 1817, p. 183, the description of a Thermometrical Barometer, by which it was conceived that acces­sible heights might with convenience be measured; and may therefore not be uninterested by the account of an actual measurement made with it. Having occasion last summer to visit Carnarvon, which would afford an opportunity of trying the instrument on the known height of Snowdon, and being aware that in 3550 feet the variations of the boiling temperature were not to be considered uniform, as they might in small elevations, on which alone I had before tried the experiment, I wished to provide myself previously with a table for making the necessary corrections; and from Dr. Ureʼs paper, Philosophical Transactions, 1818, p. 338, was supplied with data for the calculation. The law, which he discovers by approximation and lays down, is this: that, the elastic force of the air, or length of the column of mercury in the barometer being supposed 30 inches when water boils at 212° of Fahrenheit, 30/1,23 will be the length of the column at 202°; 30/1,2 x 1,24 the length at 192°; and so on progres­sively, adding another increased divisor for every 10° of ther­mometrical temperature. For my purpose it was necessary to calculate the variations at smaller intervals than ten degrees, and particularly to obtain those between 212° and 202°, by getting a series of divisors for each degree, instead of the simple divisor of 1,23 for the whole. By taking the tenth of the logarithm of 1,23, the uniform divisor appears to be 1,021; but to make the successive divisors increase at the lower temperatures, as Dr, Ure does, suppose them to be taken thus;

scholarly journals Influence of grass lawns on the summer thermal environment and microclimate of heritage sites: a case study of Fuling mausoleum, China

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaoyu Wang ◽  
Peng Liu ◽  
Gongwen Xu
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Thermal Environment ◽  
Measurement Data ◽  
Ground Temperature ◽  
Rapid Urbanization ◽  
Actual Measurement ◽  
Heritage Sites ◽  
Human Thermal Comfort ◽  
The Impact

AbstractThe thermal environment and microclimate of heritage sites has been severely impacted by rapid urbanization. This study collected various meteorological measurement data as a reference for computational fluid dynamics (CFD) simulation settings. Then CFD was applied to simulate the impact of lawns on the thermal environment and microclimate of Fuling Mausoleum. We found that lawns and soil can cool the air through evaporation, and thus have a specific cooling effect on the bricked ground. Simulations with the lawns, the bricked ground temperature decreased by 1.56–17.54 °C than that simulations without the lawns at 14:00, a decrease of 2.68%–24.20%. Under normal circumstances, when the wind speed or relative humidity increased, the ground temperature dropped. Greenbelt vegetation can adjust the microclimate and human thermal comfort indicators. The consistency of the difference between the actual measurement and the CFD simulation results shows that CFD simulation can thus accurately reflect the internal temperature field distribution if the selection of simulation parameters is reasonable. Theoretical calculation and analysis, experimental measurement research, and modern computer simulation analysis methods applied together constitute a complete system for studying modern physical environmental problems and can provide reliable and economic results.

scholarly journals Short communication: a new dataset for estimating organic carbon storage to 3 m depth in soils of the northern circumpolar permafrost region

2013 ◽  
Vol 6 (1) ◽  
pp. 73-93 ◽  
Author(s):  
G. Hugelius ◽  
C. Tarnocai ◽  
J. G. Bockheim ◽  
P. Camill ◽  
B. Elberling ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Geographical Information Systems ◽  
Mineral Soil ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Geographical Information ◽  
Permafrost Region ◽  
Depth Range ◽  
C Cycle ◽  
Permafrost Regions

Abstract. High latitude terrestrial ecosystems are key components in the global carbon (C) cycle. The Northern Circumpolar Soil Carbon Database (NCSCD) was developed to quantify stocks of soil organic carbon (SOC) in the northern circumpolar permafrost region (18.7 × 106 km2). The NCSCD is a digital Geographical Information systems (GIS) database compiled from harmonized regional soil classification maps, in which data on soil coverage has been linked to pedon data from the northern permafrost regions. Previously, the NCSCD has been used to calculate SOC content (SOCC) and mass (SOCM) to the reference depths 0–30 cm and 0–100 cm (based on 1778 pedons). It has been shown that soils of the northern circumpolar permafrost region also contain significant quantities of SOC in the 100–300 cm depth range, but there has been no circumpolar compilation of pedon data to quantify this SOC pool and there are no spatially distributed estimates of SOC storage below 100 cm depth in this region. Here we describe the synthesis of an updated pedon dataset for SOCC in deep soils of the northern circumpolar permafrost regions, with separate datasets for the 100–200 cm (524 pedons) and 200–300 cm (356 pedons) depth ranges. These pedons have been grouped into the American and Eurasian sectors and the mean SOCC for different soil taxa (subdivided into Histels, Turbels, Orthels, Histosols, and permafrost-free mineral soil taxa) has been added to the updated NCSCDv2. The updated version of the database is freely available online in several different file formats and spatial resolutions that enable spatially explicit usage in e.g. GIS and/or terrestrial ecosystem models. The potential applications and limitations of the NCSCDv2 in spatial analyses are briefly discussed. An open access data-portal for all the described GIS-datasets is available online at: http://dev1.geo.su.se/bbcc/dev/v3/ncscd/download.php. The NCSCDv2 database has the doi:10.5879/ECDS/00000002.

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