Effect of Freeze–Thaw Cycles on Mechanical Strength and Microstructure of Silty Clay in the Qinghai–Tibet Plateau

2022 ◽  
Vol 36 (1) ◽  
Author(s):  
Wenbin Xu ◽  
Xiaochun Wang
Keyword(s):  
Mechanical Strength ◽  
Tibet Plateau ◽  
Silty Clay ◽  
Freeze Thaw ◽  
Qinghai Tibet Plateau

Interactions between freeze–thaw actions, wind erosion desertification, and permafrost in the Qinghai–Tibet Plateau

2016 ◽  
Vol 85 (2) ◽  
pp. 829-850 ◽  
Author(s):  
Shengbo Xie ◽  
Jianjun Qu ◽  
Xiangtian Xu ◽  
Yingjun Pang
Keyword(s):  
Wind Erosion ◽  
Tibet Plateau ◽  
Freeze Thaw ◽  
Qinghai Tibet Plateau

scholarly journals Freeze-thaw processes of active layer regulate soil respiration of alpine meadow in the permafrost region of the Qinghai-Tibet Plateau

2019 ◽  
Author(s):  
Junfeng Wang ◽  
Qingbai Wu ◽  
Ziqiang Yuan ◽  
Hojeong Kang
Keyword(s):  
Soil Respiration ◽  
Active Layer ◽  
Alpine Meadow ◽  
Water Status ◽  
Tibet Plateau ◽  
Permafrost Region ◽  
Permafrost Degradation ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Qinghai Tibet Plateau

Abstract. Freezing and thawing action of the active layer plays a significant role in soil respiration (Rs) in permafrost regions. However, little is known about how the freeze-thaw process regulates the Rs dynamics in different stages for the alpine meadow underlain by permafrost on the Qinghai-Tibet Plateau (QTP). We conducted continuous in-situ measurements of Rs and freeze-thaw process of the active layer at an alpine meadow site in the Beiluhe permafrost region of QTP to determine the regulatory mechanisms of the different freeze-thaw stages of the active layer on the Rs. We found that the freezing and thawing process of active layer modified the Rs dynamics differently in different freeze-thaw stages. The mean Rs ranged from 0.56 to 1.75 μmol/m2s across the stages, with the lowest value in the SW stage and highest value in the ST stage; and Q10 among the different freeze-thaw stages changed greatly, with maximum (4.9) in the WC stage and minimum (1.7) in the SW stage. Patterns of Rs among the ST, AF, WC, and SW stages differed, and the corresponding contribution percentages of cumulative Rs to annual total Rs were 61.54, 8.89, 18.35, and 11.2 %, respectively. Soil temperature (Ts) was the most important driver of Rs regardless of soil water status in all stages. Our results suggest that as the climate warming and permafrost degradation continue, great changes in freeze-thaw process patterns may trigger more Rs emissions from this ecosystem because of prolonged ST stage.

scholarly journals Barley Seedlings in Response to Salinity and Artemisinin Stress in the Present of Freeze-Thaw Stress

2022 ◽  
Author(s):  
Zhang Wei ◽  
Guozhang Bao ◽  
Tang Wenyi ◽  
Dai Gejun ◽  
Xiao Jing ◽  
...  
Keyword(s):  
Artemisia Annua ◽  
Soil Salinization ◽  
Tibet Plateau ◽  
Sod Activity ◽  
Freeze Thaw ◽  
Mda Content ◽  
Use Efficiency ◽  
Relative Electrical Conductivity ◽  
Scavenging Efficiency ◽  
Qinghai Tibet Plateau

Abstract In the Qinghai-Tibet Plateau, both the large daily temperature difference and soil salinization make plants susceptible to abiotic stresses such as freeze-thaw and salinity. Meanwhile, crops in this area could be subjected to the influence of artemisinin, an allelochemical exuded by Artemisia annua. In the context of freeze-thaw and salinity stresses, artemisinin was induced as an allelopathy stress factor to explore the physiological response of highland barley, including the relative electrical conductivity (RC), soluble protein (SP) content, malondialdehyde (MDA) content, antioxidant enzyme activity, and water use efficiency (WUE).There data suggested that artemisinin weakened the self-osmotic adjustment ability of seedlings, reducing the SOD activity in scavenging efficiency of reactive oxygen species, then causing oxidative damage to cell membrane of seedlings, which significantly increases the content of RC and MDA. Artemisinin stress can reduce the WUE of seedlings and weaken the photosynthesis intensity of seedlings as well. In a word, salinity stress and artemisinin respectively showed a synergistic compound relationship with freeze-thaw stress,

scholarly journals Soil respiration of alpine meadow is controlled by freeze–thaw processes of active layer in the permafrost region of the Qinghai–Tibet Plateau

2020 ◽  
Vol 14 (9) ◽  
pp. 2835-2848
Author(s):  
Junfeng Wang ◽  
Qingbai Wu ◽  
Ziqiang Yuan ◽  
Hojeong Kang
Keyword(s):  
Soil Respiration ◽  
Active Layer ◽  
Alpine Meadow ◽  
Tibet Plateau ◽  
Permafrost Region ◽  
Permafrost Degradation ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Qinghai Tibet Plateau

Abstract. Freezing and thawing action of the active layer plays a significant role in soil respiration (Rs) in permafrost regions. However, little is known about how the freeze–thaw processes affect the Rs dynamics in different stages of the alpine meadow underlain by permafrost in the Qinghai–Tibet Plateau (QTP). We conducted continuous in situ measurements of Rs and freeze–thaw processes of the active layer at an alpine meadow site in the Beiluhe permafrost region of the QTP and divided the freeze–thaw processes into four different stages in a complete freeze–thaw cycle, comprising the summer thawing (ST) stage, autumn freezing (AF) stage, winter cooling (WC) stage, and spring warming (SW) stage. We found that the freeze–thaw processes have various effects on the Rs dynamics in different freeze–thaw stages. The mean Rs ranged from 0.12 to 3.18 µmol m−2 s−1 across the stages, with the lowest value in WC and highest value in ST. Q10 among the different freeze–thaw stages changed greatly, with the maximum (4.91±0.35) in WC and minimum (0.33±0.21) in AF. Patterns of Rs among the ST, AF, WC, and SW stages differed, and the corresponding contribution percentages of cumulative Rs to total Rs of a complete freeze–thaw cycle (1692.98±51.43 g CO2 m−2) were 61.32±0.32 %, 8.89±0.18 %, 18.43±0.11 %, and 11.29±0.11 %, respectively. Soil temperature (Ts) was the most important driver of Rs regardless of soil water status in all stages. Our results suggest that as climate change and permafrost degradation continue, great changes in freeze–thaw process patterns may trigger more Rs emissions from this ecosystem because of a prolonged ST stage.

The Response of Shallow Groundwater Levels to Soil Freeze–Thaw Process on the Qinghai‐Tibet Plateau

Ground Water ◽  
2018 ◽  
Vol 57 (4) ◽  
pp. 602-611 ◽  
Author(s):  
Licong Dai ◽  
Xiaowei Guo ◽  
Yangong Du ◽  
Fawei Zhang ◽  
Xun Ke ◽  
...  
Keyword(s):  
Shallow Groundwater ◽  
Tibet Plateau ◽  
Groundwater Levels ◽  
Freeze Thaw ◽  
Qinghai Tibet Plateau

Preparation and Performance of Fly Ash Brick

2014 ◽  
Vol 1081 ◽  
pp. 322-326
Author(s):  
Jian Bo Chen ◽  
Pei Xin Li ◽  
Yan Mu ◽  
Hong Xiao Ma ◽  
Xiao Lin Ren
Keyword(s):  
Thermal Conductivity ◽  
Fly Ash ◽  
Breaking Strength ◽  
Building Construction ◽  
Tibet Plateau ◽  
Technological Parameters ◽  
Freeze Thaw ◽  
Dry Shrinkage ◽  
And Performance ◽  
Qinghai Tibet Plateau

This paper uses the industrialization production device to study the factors that affecting the performance of fly ash products. Through adopting the appropriate material ratio and technological parameters, the load-bearing standard bricks with large admixing amount of fly ash were successful developed. The mixing amount of fly ash has reached about 50%, and the bricks were got the production application in the industrialized device which annual output is 400 million pieces. The product performances are referred to the requirements specified in JC 239-2001, and the compressive strength reach 16.6 MPa and the breaking strength reach 3.8 MPa. The product has the low thermal conductivity and qualified freeze-thaw resistance, dry shrinkage. The products were got widespread popularization and application in the building construction of Qinghai-Tibet Plateau.

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