scholarly journals Analysis on Cooling Effect of Crushed-Rocks Embankment of Qinghai-Tibet High-Grade Road

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Dongqing Li ◽  
Kun Zhang ◽  
Gangqiang Tong ◽  
Feng Ming ◽  
Xing Huang
Keyword(s):  
Wind Tunnel Test ◽  
Resistance Coefficient ◽  
Cooling Effect ◽  
Tibet Plateau ◽  
Crushed Rock ◽  
High Grade ◽  
Calculation Results ◽  
Cooling Effects ◽  
Qinghai Tibet Plateau

In order to study the cooling effect of the crushed-rocks embankment, the permeability and the inertial resistance coefficient were measured by the wind tunnel test of spheres with a diameter of 20 cm, and then the stabilities of the closed crushed-rocks embankment with the wide pavement, the closed crushed-rocks embankment with the narrow pavement, and the duct-ventilated and closed crushed-rocks embankment were calculated. In the next 50 years, assuming that the temperature in Qinghai-Tibet plateau will rise by 2.6°C condition, the cooling effects of these three special high-grade embankment structures were studied. The test results and the numerical calculation results show that the relationship between pressure gradient and seepage velocity in the spheres layer diverges completely from Darcy’s law, and it shows a nice quadratic nonlinear relationship. Stabilities of those two closed crushed-rock embankments without the duct-ventilated structure could be destroyed because of the high permafrost temperature under embankments. The duct-ventilated and closed crushed-rocks embankment can cool down the permafrost effectively and raise the permafrost table and ensure the long-term thermal stability of permafrost under road.

Response of phosphorus fractions to land-use change followed by long-term fertilization in a sub-alpine humid soil of Qinghai–Tibet plateau

2018 ◽  
Vol 19 (3) ◽  
pp. 1109-1119 ◽  
Author(s):  
Xiaolei Sun ◽  
Meng Li ◽  
Guoxi Wang ◽  
Marios Drosos ◽  
Fulai Liu ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Phosphorus Fractions ◽  
Tibet Plateau ◽  
Qinghai Tibet Plateau

scholarly journals Characteristics of Atmospheric Dustfall and Soil Magnetic Susceptibility and Environmental Significance in Xining City

2021 ◽  
Vol 290 ◽  
pp. 03001
Author(s):  
Qiang Peng ◽  
Yongjuan Sun
Keyword(s):  
Heavy Metal ◽  
Magnetic Susceptibility ◽  
Soil Profile ◽  
Central City ◽  
Soil Samples ◽  
Tibet Plateau ◽  
Dust Fall ◽  
Important Means ◽  
Qinghai Tibet Plateau

Magnetic susceptibility is an important means to quickly and economically monitor the enrichment of surrounding environmental elements. As a regional central city on the Qinghai-Tibet Plateau, the relationship between atmospheric dust magnetic susceptibility and heavy metal content in Xining area is relatively lacking. In this paper, the magnetic susceptibility and geochemical element content of the collected dust samples, loess samples, surface soil samples and soil profile samples obtained through long-term observations are analyzed. The results show that the magnetic susceptibility of the dust-fall samples is the highest, the soil samples are the second, and the loess samples are the lowest; the magnetic susceptibility of the dust-fall samples in Xining City has a significant correlation with the elements Cd, Cr, Ni, Cu, Pb, Zn and Hg, and the magnetic susceptibility can be used as an indicator of heavy metal in the soil; the elements Cr, Ni, Cu, Zn and As in the soil profile are enriched at 20 cm or 30 cm, which is related to the leaching of surface elements.

scholarly journals A Preliminary Study on the Long-Term Structural Stability of Ventilation Ducts in Cold Regions

2019 ◽  
Vol 5 (6) ◽  
pp. 1227-1234 ◽  
Author(s):  
Xuejun Chen ◽  
Lei Wang ◽  
Zhikui Liu ◽  
Yinghong Qin
Keyword(s):  
Structural Stability ◽  
Ground Surface ◽  
Field Studies ◽  
Tibet Plateau ◽  
Thermally Induced ◽  
Ventilation Ducts ◽  
Induced Stresses ◽  
Fixed End ◽  
Qinghai Tibet Plateau

The construction of roadways in permafrost regions modifies ground-surface conditions and consequently, negatively varies thermal stability of the underlying frozen soils. To avoid the thawing of the permafrost layer under the scenario of global warming, roadways are usually laid on a built-up embankment, which not only disperses the traffic loads to underlying layers but also minimize the thermal disturbance. In the embankment, duct ventilation, or called air duct, can be embedded to further cool the underlying permafrost. While the thermal performance of duct ventilations has been well documented, the long-term structural stability of duct ventilation remains unknown. This study examines the structural stress of ventilation ducts that are placed in harsh weather such as the Qinghai-Tibet Plateau. The ducts are currently buried in the embankment filler, with the wind-outlet and -inlet ends exposed and cantilevered out of the embankment. Field studies found that the exposed parts have plagued cracking and even failures, especially at the fixed end of the cantilevered part. Damages of these concrete ducts are attributed to cyclic freezing-thawing attack, thermally-induced stresses, moisture-induced stresses, and concrete swelling. These physical attacks are caused by the harsh weather in the Qinghai-Tibet plateau. It is recommended to insulate the exposed part of the ducts and to fabricate durable and dense concrete ducts.

scholarly journals The Regulation of Adaptation to Cold and Drought Stresses in Poa crymophila Keng Revealed by Integrative Transcriptomics and Metabolomics Analysis

2021 ◽  
Vol 12 ◽  
Author(s):  
Yan Wang ◽  
Xin-Yu Li ◽  
Cai-Xia Li ◽  
Yuan He ◽  
Xin-Yi Hou ◽  
...  
Keyword(s):  
Sugar Transport ◽  
Tibet Plateau ◽  
Harsh Environments ◽  
Primary Role ◽  
Targeted Metabolomics ◽  
Myb Gene ◽  
Widely Targeted Metabolomics ◽  
Coa Reductase ◽  
Qinghai Tibet Plateau

Poa crymophila Keng is highly adaptable to long-term low temperature and drought conditions, making it a desirable foraging grass of the Qinghai-Tibet Plateau. Here, the widely targeted metabolomics and comparative transcriptome analyses were utilized for the discovery of metabolites and genes in P. crymophila in response to cold and drought stresses. P. crymophila were exposed to −5°C for 24 h and recovered to 22°C for 48 h, as well as drought for 10 days followed by re-watering for 1 day. In total, 779 metabolic features were assigned to metabolites and 167,845 unigenes were generated. Seventeen compounds showed significant up-regulation (variable importance in project >1) under both stresses in the metabolic profiling, mainly annotated as carbohydrates, flavones, and phenylpropanoids. The genes which were positively correlated with these metabolites were assigned to pathways (sucrose-starch, raffinose, phenylpropanoid, and flavone metabolism) using the Mapman software package. Alpha-amylase, beta-fructofuranosidase, and sugar transport genes degraded the glucose and starch to small molecule sugars for the purpose of osmotic adjustment and to provide more energy for the growth of P. crymophila in an adverse environment. The induction of cinnamoyl-CoA reductase (CCR) and the MYB gene as well as the sharp increase in schizandrin, a kind of lignan, showed that this likely has the closest connection with the tolerance to both stresses. Four significantly induced flavone compounds are probably involved in reducing oxidative damage. Our results indicated that activation of the phenlypropanoid pathway plays the primary role in P. crymophila adapting to harsh environments. This study showed the mechanism of P. crymophila responding to both cold and drought stresses and showed the discovery of a new biological regulator against stresses.

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