scholarly journals Research on the Influence of Moisture Condition on the Mechanical Properties and Microstructure of Sandstone

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zuosen. Luo ◽  
Zuoxiang. Zhu ◽  
Hao Bai ◽  
Daxiang Liu ◽  
Qiancheng. Sun
Keyword(s):  
Water Content ◽  
Gradual Increase ◽  
Triaxial Compression ◽  
Point Of View ◽  
Three Gorges Reservoir Area ◽  
Moisture Condition ◽  
The Three Gorges ◽  
The Stability ◽  
Moisture Conditions ◽  
The Impact

The sandstone from the dry to saturated state shows obvious deterioration characteristics. Taking the sandstone of a slope in the Three Gorges Reservoir area as the research object, uniaxial/triaxial compression of sandstone samples with different water-bearing states (dry, natural, and saturated) is carried out to study the changes in macromechanical properties of sandstone under different water-bearing states. Combined with NMR and SEM, the characteristics of microstructure of sandstone under different moisture conditions were studied. The results show that, with the increase of water content, the macromechanical parameters of sandstone gradually decrease, and the fine and microstructure characteristics are characterized by the gradual increase in the number of pores and the gradual increase in pore size. Based on the PFC2D software, considering the weakening effect of water on the partial cementation from a mesoscopic point of view, it is proposed to use soft and hard contacts to simulate the changes in the degree of cementation between particles under different water-bearing conditions and to study the impact of sandstone micromechanical parameters with changes in water content. Related research results can provide theoretical guidance for the stability evaluation of wading rock mass engineering.

The Discharge Outlets Layout Optimization of Typical River Section in the Three Gorges Reservoir Area

2014 ◽  
Vol 955-959 ◽  
pp. 3287-3294
Author(s):  
Zheng Wang ◽  
Ying Liu
Keyword(s):  
Water Quality ◽  
Three Gorges Reservoir ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Mixing Zone ◽  
Unit Load ◽  
Reservoir Area ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
The Impact

To improve water quality and alleviate pollution in Changshou-Fuling section of the Three Gorges Reservoir Area, an analysis methodology of regional key discharge outlet based on hydrodynamic-water quality model was developed. The EFDC model was used to study the impact of different discharge outlets on the transport of contamination in the study area by using the concept of pollutant mixing zone and pollutant mixing zone per unit load. Model calibration was conducted using observed data in 2008. Results indicated that EFDC could perfectly simulate hydrodynamics characteristics and contaminant transport process. Calculated results of pollutant mixing zone per unit load showed that the discharge outlet location in Fuling is more reasonable than that in Changshou. This study provides useful information for optimization of discharge outlets location and prediction of pollutant mixing zone in the study area, which is important for the government to make water pollution control measures.

scholarly journals Anthocyanins: Factors Affecting Their Stability and Degradation

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1967
Author(s):  
Bianca Enaru ◽  
Georgiana Drețcanu ◽  
Teodora Daria Pop ◽  
Andreea Stǎnilǎ ◽  
Zorița Diaconeasa
Keyword(s):  
Antimicrobial Properties ◽  
Point Of View ◽  
Water Soluble ◽  
Factors Affecting ◽  
Color Palette ◽  
Number Of Factors ◽  
Major Disadvantage ◽  
Phenolic Group ◽  
The Stability ◽  
The Impact

Anthocyanins are secondary metabolites and water-soluble pigments belonging to the phenolic group, with important functions in nature such as seed dispersal, pollination and development of plant organs. In addition to these important roles in plant life, anthocyanins are also used as natural pigments in various industries, due to the color palette they can produce from red to blue and purple. In addition, recent research has reported that anthocyanins have important antioxidant, anticancer, anti-inflammatory and antimicrobial properties, which can be used in the chemoprevention of various diseases such as diabetes, obesity and even cancer. However, anthocyanins have a major disadvantage, namely their low stability. Thus, their stability is influenced by a number of factors such as pH, light, temperature, co-pigmentation, sulfites, ascorbic acid, oxygen and enzymes. As such, this review aims at summarizing the effects of these factors on the stability of anthocyanins and their degradation. From this point of view, it is very important to be precisely aware of the impact that each parameter has on the stability of anthocyanins, in order to minimize their negative action and subsequently potentiate their beneficial health effects.

scholarly journals The Concept of Multipolarity: Diversity of Approaches and Interpretations

2021 ◽  
Vol 23 (3) ◽  
pp. 424-445
Author(s):  
Vladislav S. Soluianov
Keyword(s):  
Regional Integration ◽  
International System ◽  
World Politics ◽  
Point Of View ◽  
Regional Powers ◽  
Regional Approach ◽  
The Us ◽  
The World ◽  
The Stability ◽  
The Impact

The author regards multipolarity as a question open for discussion, the variety of answers to which contribute not only to the comprehensive understanding of the phenomenon, but also to the perception of processes taking place in the world politics. The content of the multipolarity concept is revealed through the perspectives of realism, neorealism, civilizational approach, regional approach, liberalism, and constructivism. From the realism perspective, multipolarity can be considered as an objective reflection of the world development. The foundation of multipolarity consists in the growth of economic, military, and political potential of non-Western powers and the weakening of the US position as a global leader. Neorealism views multipolarity as a property of the international system which affects the behavior of states. The civilizational approach focuses on identifying civilizations as new actors and centers of power on the world stage. The regional approach highlights the importance of the increasing regionalization processes and creation of regional integration systems, which contribute to the formation of multipolarity in the context of the rise of regional powers and weakening of the USs world position. Liberalism seeks to assess the impact of multipolarity on the stability and security of the international system. Along with the predictable attitude to multipolarity as a threat to peace and security, there is another more optimistic point of view. Constructivism regards multipolarity as a foreign policy discourse and a project of several states, primarily Russia. The results allow to see multipolarity from different perspectives and develop a more comprehensive and objective understanding of this phenomenon.

scholarly journals Particle Flow Code Simulation of the Characteristics of Crack Evolution in Rock-Like Materials with Bent Cracks

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhanguo Ma ◽  
Shixing Cheng ◽  
Peng Gong ◽  
Jun Hu ◽  
Yongheng Chen
Keyword(s):  
Elasticity Modulus ◽  
Gradual Increase ◽  
Simulation Method ◽  
Two Dimensions ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Crack Evolution ◽  
Underground Engineering ◽  
The Stability ◽  
The Impact

The distribution and propagation of rock cracks have a significant impact on geotechnical engineering. Taking rock-like materials with bent cracks as the research object, the particle flow code in two dimensions numerical simulation method was used to study the impact of the bend number on rock-like materials strength and crack evolution. According to the results, when the bend number was 1, 3, and 7, the strength of the specimens gradually increased; the elasticity modulus did not change significantly with the crack bend number. Uniaxial compression generated tensile cracks in all the specimens with bent cracks, but in terms of failure mode, the specimens with 0 bend tended to suffer penetrating failure along the fracture strike, while the specimens with 1, 3, and 7 bend tended to suffer penetrating failure along the diagonal direction. Both the fractal dimension and bend number were positively correlated with strain; with the gradual increase of the stress percentage, the damage variable of the specimens gradually increased at a growing rate. The research results provide a reference for predicting the stability of the underground engineering surrounding rocks containing bent cracks.

scholarly journals Landscape Dynamics Improved Recreation Service of the Three Gorges Reservoir Area, China

2021 ◽  
Vol 18 (16) ◽  
pp. 8356
Author(s):  
Dengyue Zhao ◽  
Mingzhu Xiao ◽  
Chunbo Huang ◽  
Yuan Liang ◽  
Ziyue An
Keyword(s):  
Three Gorges Reservoir ◽  
Temporal Variations ◽  
Landscape Dynamics ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
The Three Gorges ◽  
Vegetation Landscape ◽  
Recreation Service ◽  
Spatio Temporal ◽  
The Impact

Spatio-temporal variations of recreation service not only could help to understand the impact of cultural services on human well-being but also provides theoretical and technical support for regional landscape management. However, previous studies have avoided deeply quantifying and analyzing it or have simply focused on assessing recreational service at a single period in time. In this study, we used the InVEST model to evaluate the spatio-temporal variations of recreation service in the Three Gorges Reservoir Area and demonstrated the impact of recreation service on landscape dynamics. The results demonstrated that recreation service increased significantly and presented a significant spatial heterogeneity. Although afforestation and urban expansion both could significantly increase recreation service, the recreation service proxy of the non-vegetation landscape is far higher than that of the vegetation landscape. This finding indicated that human landscape is more attractive to tourists than the natural landscape, so we recommend to strengthen the infrastructure construction for enhancing the accessibility of natural landscapes. Moreover, we propose other constructive suggestions and landscape-design solutions for promoting recreation service. This study shifted the static environmental health assessment to the analysis of recreation service dynamics, bridging the regulatory mechanisms of ecosystem services involved in cultural services.

Soil erosion in the Three Gorges Reservoir area

Soil Research ◽  
2011 ◽  
Vol 49 (3) ◽  
pp. 212 ◽  
Author(s):  
Xibao Xu ◽  
Yan Tan ◽  
Guishan Yang ◽  
Hengpeng Li ◽  
Weizhong Su
Keyword(s):  
Soil Erosion ◽  
Three Gorges Reservoir ◽  
Storage Period ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Area ◽  
Modis Ndvi ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
The Impact

Spatial and temporal change in soil erosion in the Three Gorges Reservoir area since the water storage of the reservoir began filling to 135 m in 2003 is poorly understood. Using a modified soil erosion model, this study quantifies and analyses change in the extent and intensity of soil erosion in the region from 2000 to 2008. MODIS-NDVI remote sensing data (with 250 m spatial resolution) are used in the modelling and analysis of the study. The total amount, area, and intensity of soil erosion in the reservoir region presented a declining trend from 2000 to 2008. Yet there was an anomaly in the trend, in which extreme soil erosion occurred in 2003 and lasted until 2005. The average volume of soil erosion per year decreased by 4.10 × 106 t and the mean area of land experiencing soil erosion reduced by 1129.6 km2 from the pre-storage period (2000–02) to post-storage period II (2006–08). Land suffering soil erosion at high, very high, and severe levels mainly comprises forest and cropland on slopes with gradients ≥15° and is largely distributed in the eastern and south-western sections of the reservoir area. Land experiencing soil erosion at slight or moderate levels mainly involves cropland and forest on slopes with gradients ≥10° in the central section of the reservoir area. The impact of the Three Gorges Project on soil erosion since 2000 has been mainly mediated through three mechanisms: near-resettlement of rural and urban people; increased frequency and severity of geological hazards induced by rising storage of the reservoir; and implementation of ecological projects in the region. Through the former two mechanisms, soil erosion in the affected communities has been exacerbated, while the ongoing ecological projects appear to offset both the extent and intensity of soil erosion in the reservoir region. Other important factors influencing soil erosion include urban reconstruction and expansion, varying intensity of precipitation, and soil degradation.

scholarly journals Transpiration and water use efficiency of maize in different soil moisture conditions

2021 ◽  
Vol 24 (2) ◽  
pp. 105-109
Author(s):  
Jana Klimešová ◽  
Hana Středová ◽  
Agnieszka Klimek-Kopyra ◽  
Tomáš Středa
Keyword(s):  
Soil Moisture ◽  
Water Use Efficiency ◽  
Water Content ◽  
Water Use ◽  
Global Radiation ◽  
Corn Cobs ◽  
Horticultural Crops ◽  
Use Efficiency ◽  
Moisture Conditions ◽  
The Impact

Abstract Globally, agriculture accounts for 80–90% of the fresh water used by humans, and in many crop production systems; this water use is unsustainable. Irrigation of large areas of field and horticultural crops is impossible. Studies of the impact of drought on important field and horticultural crops are necessary to estimate dimensions of adaptation and mitigation measures to climate change. For this purpose, maize was monitored as a model crop in this study. In a three-year experiment (i) using the sap flow measurement method, the transpiration of maize was evaluated during flowering and grain filling, (ii) water use efficiency (WUE) was evaluated in four soil moisture conditions. The intensity of transpiration was closely correlated with the values of global radiation and vapor pressure deficit. However, soil water content was a major factor influencing transpiration under drought stress. The transpiration decreased when water content in the soil reached 28% of available water holding capacity (AWHC), but the yield of corn cobs decreased only under stress of 25% AWHC. Thus, the yield reacted less sensitively to lower water availability than transpiration. WUE increased with decreasing transpiration. Statistically significantly higher WUE was already observed at a water content of 42% AWHC, however, a higher WUE did not lead to a higher yield of corn cobs.

Effect of storage temperature on the crispness, colour and bioactive compounds of an orange snack obtained by freeze-drying

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Marilú Andrea Silva-Espinoza ◽  
María del Mar Camacho ◽  
Nuria Martínez-Navarrete
Keyword(s):  
Vitamin C ◽  
Water Content ◽  
Bioactive Compounds ◽  
Storage Temperature ◽  
Storage Period ◽  
Point Of View ◽  
Total Phenolic ◽  
Content Type ◽  
Freeze Dried ◽  
The Stability

PurposeA healthy and easy-to-use orange snack obtained from the freeze-dried orange pulp puree is proposed. Once the commercial packaging of the snack has been opened, the effect of conventional home storage temperature on its physicochemical properties and on the content of bioactive compounds has been studied. This research aims to recommend the consumer, and therefore the manufacturer, the best conditions for home storage of this product, keeping its nutritional quality and antioxidant capacity, as well as maintaining its colour and crispness.Design/methodology/approachThe water content, water activity, hygroscopicity, crispness, colour, vitamin C, β-carotene, total phenolic compounds and antioxidant activity were characterised both when the orange snack was newly obtained and after one, two and six months of storage inside zipper bags, at 4 and 20 ºC.FindingsThe results indicated that, in these conditions, the orange snack increased its water content, causing a loss in both its porosity and its characteristic crispness. Nevertheless, the bioactive compounds remained stable throughout the storage period, with the exception of β-carotene, the content of which decreased markedly when the orange snack was stored at 20 ºC.Originality/valueFew studies have evaluated the stability of food products during home storage. The findings showed that the maximum storage time to ensure a proper texture of the orange snack studied is between two and six months, both at 4 and 20 ºC. However, from the point of view of the conservation of both vitamin C and, especially, of β-carotene, it is recommended that this product be stored in refrigeration.

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