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Research on the classification of life-cycle safety monitoring levels of subsea tunnels

100%

Lu J., Xue X.

Polish Maritime Research

2017

tom 24

nr Special Issue S2

As a traffic engineering project across straits or gulfs, subsea tunnel is one of the oceaneering with great construction difficulties, and the key to the success of subsea tunnel engineering lies in timely and accurate assessment of the structure safety of subsea tunnel engineering construction and life-cycle. Xiang’an Xiamen subsea tunnel is China’s first subsea tunnel which crosses complex formation conditions, engineering accidents such as collapse, sudden inflow of water or mud might occur during tunnel construction and operation. Therefore, the concept of subsea tunnel life-cycle monitoring is proposed aiming at the particularity of subsea tunnels. The variation forms of subsea tunnel mainly include large deformation, collapse, primary support cracking, water leakage, water pressure increase, steel arch corrosion, concrete corrosion, longitudinal differential settlement, etc., and classification of the life-cycle safety monitoring levels of the subsea tunnel is conducted based on risk assessment theory and risk level management benchmark to determine the possible variation forms in the monitoring level segments. The research results will provide reference for the subsea tunnel life-cycle monitoring, disaster warning as well as risk management under construction or to be built at home and abroad

Water entry in jujube fruit and its relationship with cracking

61%

Li N., Fu L., Song Y., Li J., Xue X., Li S., Li L.

Acta Physiologiae Plantarum

2019

tom 41

nr 09

Cracking is caused by physiological stress during the development of jujube fruit, and this causes considerable economic losses to fruit producers. The aim of this study was to clarify the mechanisms of water entry into the fruit and the events that lead to cracking. Differences in water absorption by fruit stalks and surfaces were observed in a cracking-sensitive variety (Ziziphus jujuba Mill. ‘Hupingzao’) and a cracking-resistant variety (Ziziphus jujuba Mill. ‘Yuanlingzao’). The response of the fruit surface to water absorption was studied, and the relationship between stomatal characteristics and cracking was analyzed. The cracking rate of ‘Hupingzao’ was higher during the coloring period. The relative amount of water absorbed through the fruit stalk of ‘Yuanlingzao’ after 10 h was 1.22 times higher than that of ‘Hupingzao’ during the coloring period. The rate of water absorption through the fruit surface of ‘Hupingzao’ was higher than that of ‘Yuanlingzao’ during the coloring period (3.73 and 3.04, respectively). Water was transported by the vascular bundle after entering the fruit through the fruit stalk, but was mainly distributed around the stomata of the epidermis and near-surface cells following entry through the fruit surface. After water was absorbed by the fruit surface, surface and stomatal cracks in ‘Hupingzao’ were apparent, and the degree of cracking of the stomata worsened with increasing water absorption time. The surface of ‘Yuanlingzao’ appeared cracked with increasing immersion time, but stomatal changes were not obvious. The stomatal size and aperture in the cracking-resistant variety of jujube fruit were lower than those in the cracking-sensitive variety. Stomatal size was positively correlated with the rate of fruit cracking. Water absorption through the surface was the main factor that induced fruit cracking. Stomatal characteristics, as well as the increased and deepened fruit surface microcracks caused by stomatal water absorption, were the primary factors related to cracking.

Initial effects of experimental warming on temperature, moisture and vegetation characteristics in an Alpine meadow on the Qinghai-Tibetan Plateau

61%

Xu M.-H., Peng F., You Q.-G., Guo J., Tian X.-F., Liu M., Xue X.

Polish Journal of Ecology

2014

tom 62

nr 3

The ongoing warming in the Qinghai-Tibetan Plateau leads to changes in ecosystem processes while the responses of soil and vegetation are not well understand. Thus, we used infrared radiators to carry out experimental warming from July 2010 to August 2011 in an alpine meadow on the Plateau (about 4630 m above sea level) to research the responses of environmental factors and vegetation characteristics to short-term warming (1 year). The experimental design was a block design consisting of five replications and included three treatment levels: control, T1 (130 W m–2) and T2 (150 W m–2). The results showed that air temperature at 20 cm height, surface temperature and soil temperature in the 0–100 cm layers increased with warming. The biggest differences of T1 (1.66°C) and T2 (2.34 °C) appeared on the surface and at 20 cm depth, whereas the biggest amplitudes of T1 (27.15%) and T2 (35.81%) all occurred at 100 cm depth. Soil moisture showed different trends with warming in different soil layers. In the 0–40 cm layers, soil moisture decreased with warming. The biggest differences (–2.97% for T1 and –2.73% for T2) and amplitudes (–18.07% for T1 and –16.64% for T2) all appeared at 10 cm depth. In the 60–100 cm layers, soil moisture increased with warming. The biggest differences (2.53% for T1 and 6.45% for T2) and amplitudes (11.39% for T1 and 29.05% for T2) all occurred at 100 cm depth. Relative to control, vegetation height and aboveground biomass increased significantly in T1 and T2 (P <0.05), while vegetation coverage had not significant differences in T1 and T2 (P> 0.05). In T1 and T2, the amplitudes were 30.67% and 30.19% for vegetation height, and 36.22% and 27.87% for vegetation aboveground biomass, and 12.89% and 4.42% for vegetation coverage, respectively. In the path analysis between environment and vegetation properties, vegetation was directly affected by soil moisture at 40 cm and 60 cm depths, whereas indirectly influenced by relative humidity at 20 cm height and soil temperature at 40 cm depth. This might be related to the downward movement of the soil moisture caused by warming.

Ograniczanie wyników

1 Acta Physiologiae Plantarum

1 Polish Journal of Ecology

1 Polish Maritime Research

3 Xue X.

1 Fu L.

1 Guo J.

1 Li J.

1 Li L.

1 Li N.

1 Li S.

1 Liu M.

1 Lu J.

1 Peng F.

1 Song Y.

1 Tian X.-F.

1 Xu M.-H.

1 You Q.-G.

1 2019

1 2017

1 2014

Wyniki wyszukiwania

Research on the classification of life-cycle safety monitoring levels of subsea tunnels

Water entry in jujube fruit and its relationship with cracking

Initial effects of experimental warming on temperature, moisture and vegetation characteristics in an Alpine meadow on the Qinghai-Tibetan Plateau