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Yanhu Zhao - One of the best experts on this subject based on the ideXlab platform.
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a bounding surface model for frozen sulfate Saline silty clay considering rotation of principal stress axes
International Journal of Mechanical Sciences, 2020Co-Authors: Yanhu Zhao, Jing ZhangAbstract:Abstract Research results show that rotation of principal stress axes (RPSA) has a large influence on the mechanical properties of Soil. To study the mechanical and deformation properties of frozen Saline Soil under RPSA, in this paper, a constitutive model considering RPSA is proposed for frozen Saline Soil by considering the plastic deformation caused by the increase of principal stress amplitude and the plastic deformation caused by RPSA separately. The proposed model has the following properties: (1) For the part of principal stress amplitude increase, the critical stress ratio Mc(s)g(θ) changing with hydrostatic pressure is adopted to describe pressure melting and crushing phenomenon characteristic of frozen Saline Soil under high confining pressure. A function of plastic shear strain and plastic volumetric strain is taken as hardening parameter to control the size of the bounding surface under plastic volumetric compression mechanism. (2) Based on the experimental results, a new shape function is presented for frozen Soil, and the proposed shape function is introduced into bounding surface function and plastic potential function to control the shapes change of bounding surface and plastic potential surface. (3) For the part of RPSA, a more accurate method for determining loading direction and a formula for solving non-coaxial angle are given. A plastic modulus formula considering the effects of hydrostatic pressure, generalized shear stress, and anisotropy is proposed. A dilatancy equation which can reflect the effect of intermediate principal stress coefficient is presented. By comparing the simulated results of the proposed model with the experimental results, it is found that the proposed model not only can reflect the effect of the increase of principal stress amplitude on the mechanical and deformation behaviors of frozen Saline Soil, but also can describe the effect of RPSA on the mechanical and deformation behaviors of frozen Soil.
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an anisotropic bounding surface elastoplastic constitutive model for frozen sulfate Saline silty clay under cyclic loading
International Journal of Plasticity, 2020Co-Authors: Yanhu Zhao, Fan YuAbstract:Abstract To study the mechanical properties of frozen Saline Soil under cyclic loading, the cyclic tri-axial compressive experiments of 36 samples are performed for frozen Saline silty clay with 0.0, 0.5, 1.5 and 2.5% of Na2SO4 contents at the temperature of −6 °C, respectively. The experimental results illustrate that the effect of the salt contents and confining pressures on the strength and deformation properties of frozen sulfate Saline Soils under cyclic loading is significant. To understand the deformation characteristics of frozen sulfate Saline silty clay (this kind of Saline Soil), a bounding surface elastoplastic constitutive model is presented based on the test results and bounding surface plasticity theory. The proposed model includes the effects of salt contents and confining pressures on dynamic characteristics, therefore, it can suitably describe the dynamic stress-strain response of frozen Saline Soil under cyclic dynamic loading. This proposed model includes: (1) Critical stress ratio calculation formula, considering the effect of salt contents and confining pressures, is proposed. Critical stress ratio and bounding surface shape parameter varying with confining pressures are introduced into plastic potential surface function and bounding surface function to describe pressure melting and crushing characteristics of frozen Soils under high confining pressures. (2) The influence of the initial anisotropy and the induced anisotropy by dynamic loads on bounding surface of rotation hardening is considered. A non-associated flow rule together with a mixed hardening rule is used to describe the plastic flow rule and hardening rule of Soils during cyclic loading, respectively. (3) A radial mapping rule with mobile mapping origin is employed to simulate elastoplastic properties of Soils during cyclic loading. By comparing its simulated results with the test results of cyclic triaxial compression tests, it is found that the proposed model in this paper can well predict deformation characteristics of this kind of Saline Soil under cyclic loading.
Xiaolei Wu - One of the best experts on this subject based on the ideXlab platform.
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sphingobacterium suaedae sp nov isolated from the rhizosphere Soil of suaeda corniculata
International Journal of Systematic and Evolutionary Microbiology, 2015Co-Authors: Xinying Wang, Lian Xu, Xiaolei WuAbstract:A Gram-stain-negative, non-motile, non-spore-forming bacterium, designated T47T, was isolated from Saline Soil of the Suaeda corniculata rhizosphere, located on the bank of Wuliangsuhai Lake, Inner Mongolia, northern China. Strain T47T could grow at 10–40 °C (with 30 °C the optimal temperature), pH 6.0–8.0 (optimal pH 6.0) and in the presence of 0–6.0 % (w/v) NaCl [optimal 0–1.0 % (w/v)]. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain T47T formed a stable clade with Sphingobacterium composti 4M24T, Sphingobacterium bambusae IBFC2009T, Sphingobacterium paludis S37T and Sphingobacterium wenxiniae LQY-18T, with the 16S rRNA gene sequence similarities ranging from 91.9–95.4 %. Its major cellular fatty acids contained iso-C15 : 0 (39.9 %), summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c, 23.0 %), C16 : 0 (12.8 %) and iso-C17 : 0 3-OH (9.9 %). MK7 was the major menaquinone. The G+C content of the genomic DNA was 45.5 mol%. Based on the phenotypic, phylogenetic and genotypic characteristics, strain T47T represents a novel species within the genus Sphingobacterium, for which the name Sphingobacterium suaedae sp. nov. is proposed. The type strain is T47T ( = CGMCC 1.15277T = KCTC 42662T).
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marinobacter shengliensis sp nov a moderately halophilic bacterium isolated from oil contaminated Saline Soil
Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, 2015Co-Authors: Xianglin Lv, Yanan Wang, Xiaolei WuAbstract:Two moderately halophilic strains, designated SL013A34A2T and SL013A24A, were isolated from oil-contaminated Saline Soil from Shengli Oilfield, eastern China. Cells were found to be Gram-staining negative, aerobic, rod-shaped with a single polar flagellum. The isolates were found to grow at 10–40 °C (optimum 35 °C), pH 6.0–9.0 (optimum pH 8.0), and NaCl concentrations of 0.5–18.0 % (w/v) (optimum 3.0–6.0 NaCl). The 16S rRNA gene sequence analysis indicated that the isolates belong to the genus Marinobacter. Strain SL013A34A2T shares the highest 16S rRNA gene sequence similarities with strain SL013A24A (99.3 %), followed by M. hydrocarbonoclasticus CGMCC 1.7683T (97.8 %), M. vinifirmus CGMCC 1.7265T (97.8 %), and M. excellens KMM 3809T (97.4 %), respectively, but low similarities (93.8–96.4 %) with type strains of the other numbers of genus Marinobacter. DNA–DNA relatedness values of strain SL013A34A2T with strains SL013A24A, M. hydrocarbonoclasticus CGMCC 1.7683T, M. vinifirmus CGMCC 1.7265T and M. excellens KMM 3809T were 88.7, 29.2, 33.4 and 29.4 %, respectively. The major fatty acids of strain SL013A34A2T were identified as C18:1 ω9c, C16:0, C12:03-OH, C12:0, C16:1 ω9c and 10-methyl C18:0. The major respiratory quinone of strain SL013A34A2T was found to be ubiquinone-9, and its predominant polar lipids were identified as diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and unidentified glycolipid. The genomic DNA G + C content was found to be 56.1 mol %. Based on the phenotypic, genetic and chemotaxonomic characteristics, these two isolates are representatives of a novel species of the genus Marinobacter, for which the name Marinobacter shengliensis sp. nov. is proposed. The type strain is SL013A34A2T(=LMG 27740T = CGMCC 1.12758T).
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marinobacter gudaonensis sp nov isolated from an oil polluted Saline Soil in a chinese oilfield
International Journal of Systematic and Evolutionary Microbiology, 2007Co-Authors: Jun Gu, Sulin Yu, Ri Qu, Jinyi Zhao, Xiaolei WuAbstract:Two novel strains, SL014B61AT and SL014B11A, were isolated from an oil-polluted Saline Soil from Gudao in the coastal Shengli Oilfield, eastern China. Cells of strains SL014B61AT and SL014B11A were motile, Gram-negative and rod-shaped. Growth occurred at NaCl concentrations of between 0 and 15 % and at temperatures of between 10 and 45 °C. Strain SL014B61AT had Q9 as the major respiratory quinone and C16 : 0 (21.2 %), C18 : 1ω9c (20.3 %), C16 : 1ω7c (7.3 %) and C16 : 1ω9c (6.4 %) as predominant fatty acids. The G+C content of the DNA was 57.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SL014B61AT belonged to the genus Marinobacter in the class Gammaproteobacteria. Strain SL014B61AT showed the highest 16S rRNA gene sequence similarity with Marinobacter bryozoorum (97.9 %) and showed 97.8 % sequence similarity to Marinobacter lipolyticus. DNA–DNA relatedness to the reference strains Marinobacter bryozoorum and Marinobacter lipolyticus was 35.5 % and 33.8 %, respectively. On the basis of these data, it is proposed that strains SL014B61AT and SL014B11A represent a novel species, Marinobacter gudaonensis sp. nov. The type strain is strain SL014B61AT (=DSM 18066T=LMG 23509T=CGMCC 1.6294T).
Junbao Yu - One of the best experts on this subject based on the ideXlab platform.
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the spatial distribution characteristics of Soil salinity in coastal zone of the yellow river delta
Environmental Earth Sciences, 2014Co-Authors: Junbao Yu, Huifeng Wu, Di Zhou, Yunzhao Li, Yuqin Fu, Bo Guan, Guangmei Wang, Kai Ning, Jihong WangAbstract:In coastal area, salinization is a common and serious problem for crop cultivation and ecological restoration of degraded wetlands. Therefore, the Soil salinity has attracted increasing attention from farmers, government and environmental scientists. The factors controlling the Soil salinity distribution have become a hot point in Saline Soil studies. In this study, statistics and geostatistics were used to explore the distribution of Soil salinity in the Yellow River Delta (YRD) based on 150 Soil samples that were collected in June 2010. Besides the experimental work, a geographical information system technique was adopted in this study. The results showed that the Soil salinity ranged from 0.11 to 10.50 dS m(-1) and the salinity in topSoil was higher than that in subSoil in the YRD, indicating that the salt in subSoil moved up and accumulated in topSoil as a function of evaporation. There was a significant difference among Soil salinity spatial variances from different Soil depths in the YRD. Generally, Soil salinity of the topSoil was higher than that of the subSoil. Meanwhile, there were significant positive correlations in Soil salinity between different Soil depths. In addition, landforms, land uses, Soil types and Soil texture were important factors affecting Soil salinity. The current distribution of Soil salinity resulted from the comprehensive effects of anthropogenic activities and natural processes. The present study results suggest that the impacts of human activities were critical factors for salt redistribution in the coastal wetlands, which should be valuable for agricultural management and ecological restoration in the YRD.
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effects of salinity on metabolic profiles gene expressions and antioxidant enzymes in halophyte suaeda salsa
Journal of Plant Growth Regulation, 2012Co-Authors: Huifeng Wu, Linbao Zhang, Di Zhou, Jianghua Feng, Jianmin Zhao, Junbao YuAbstract:Halophyte Suaeda salsa is native to the Saline Soil in the Yellow River Delta. Soil salinity can reduce plant productivity and therefore is the most important factor for the degradation of wetlands in the Yellow River Delta. In this work we characterized the salinity-induced effects in S. salsa in terms of metabolic profiling, antioxidant enzyme activities, and gene expression quantification. Our results showed that salinity inhibited plant growth of S. salsa and upregulated gene expression levels of myo-inositol-1-phosphate synthase (INPS), choline monooxygenase (CMO), betaine aldehyde dehydrogenase (BADH), and catalase (CAT), and elevated the activities of superoxide dismutase (SOD), peroxidase (POD), CAT, and glutathione peroxidase (GPx). The significant metabolic responses included the depleted amino acids malate, fumarate, choline, phosphocholine, and elevated betaine and allantoin in the aboveground part of S. salsa seedlings as well as depleted glucose and fructose and elevated proline, citrate, and sucrose in root tissues. Based on these significant biological markers, salinity treatments induced clear osmotic stress (for example, INPS, CMO, BADH, betaine, proline) and oxidative stress (for example, SOD, POD, CAT, GPx activities), disturbed protein biosynthesis/degradation (amino acids and total protein) and energy metabolism (for example, glucose, sucrose, citrate) in S. salsa.
Fan Yu - One of the best experts on this subject based on the ideXlab platform.
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an anisotropic bounding surface elastoplastic constitutive model for frozen sulfate Saline silty clay under cyclic loading
International Journal of Plasticity, 2020Co-Authors: Yanhu Zhao, Fan YuAbstract:Abstract To study the mechanical properties of frozen Saline Soil under cyclic loading, the cyclic tri-axial compressive experiments of 36 samples are performed for frozen Saline silty clay with 0.0, 0.5, 1.5 and 2.5% of Na2SO4 contents at the temperature of −6 °C, respectively. The experimental results illustrate that the effect of the salt contents and confining pressures on the strength and deformation properties of frozen sulfate Saline Soils under cyclic loading is significant. To understand the deformation characteristics of frozen sulfate Saline silty clay (this kind of Saline Soil), a bounding surface elastoplastic constitutive model is presented based on the test results and bounding surface plasticity theory. The proposed model includes the effects of salt contents and confining pressures on dynamic characteristics, therefore, it can suitably describe the dynamic stress-strain response of frozen Saline Soil under cyclic dynamic loading. This proposed model includes: (1) Critical stress ratio calculation formula, considering the effect of salt contents and confining pressures, is proposed. Critical stress ratio and bounding surface shape parameter varying with confining pressures are introduced into plastic potential surface function and bounding surface function to describe pressure melting and crushing characteristics of frozen Soils under high confining pressures. (2) The influence of the initial anisotropy and the induced anisotropy by dynamic loads on bounding surface of rotation hardening is considered. A non-associated flow rule together with a mixed hardening rule is used to describe the plastic flow rule and hardening rule of Soils during cyclic loading, respectively. (3) A radial mapping rule with mobile mapping origin is employed to simulate elastoplastic properties of Soils during cyclic loading. By comparing its simulated results with the test results of cyclic triaxial compression tests, it is found that the proposed model in this paper can well predict deformation characteristics of this kind of Saline Soil under cyclic loading.
Wen-jun Li - One of the best experts on this subject based on the ideXlab platform.
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microbacterium halotolerans sp nov isolated from a Saline Soil in the west of china
International Journal of Systematic and Evolutionary Microbiology, 2004Co-Authors: Shu-kun Tang, Huahong Chen, Dong-jin Park, Wen-jun Li, Lihua Xu, Cheng-lin JiangAbstract:A Gram-positive short rod isolated from a Saline Soil in China was characterized using a polyphasic approach. This actinobacterium grew over a wide salinity range [0–15 % NaCl, 0–20 % KCl and 0–30 % MgCl2.6H2O (w/v); optimum concentrations for growth were 5 % NaCl, 5–10 % KCl, 10 % MgCl2.6H2O]. The optimum growth temperature and pH were 28–30 °C and 7·0–8·0, respectively. Chemotaxonomic features (peptidoglycan-type B2β with glycolyl residues; major menaquinones MK-10 and MK-11; predominating iso- and anteiso-branched cellular fatty acids; DNA G+C content 66·5 mol%) placed this organism within the genus Microbacterium. 16S rRNA gene sequence analysis confirmed this classification of the strain, but showed that it was distinct from its nearest neighbours. It formed a separate branch with type strains of the genus Microbacterium, and also shared low sequence similarity with them (<96 %). Based on phenotypic and molecular taxonomic results, it is proposed that the unknown isolate should be classified as a novel species in the genus Microbacterium, for which the name Microbacterium halotolerans sp. nov. is proposed. The type strain is YIM 70130T (=KCTC 19017T=CIP 108071T).
