Pseudo-static calculation method of the seismic residual deformation of a geogrid reinforced soil retaining wall with a liquefied backfill

The geogrid reinforced soil retaining wall is a flexible retaining wall. It will produce large deformations during earthquakes, especially on liquefied backfill soils. An index of liquefaction extent is applied to express the effect of excess pore water pressure in reinforced backfill sand during earthquakes. A geogrid reinforced soil retaining wall is represented by an isotropic vertical elastic beam. The calculation method of the seismic residual deformation of the geogrid reinforced soil retaining wall is based on the Rayleigh-Ritz method and the the Mononobe-Okabe pseudo-static method. The effect of liquefaction extent in the backfill sand is studied for seismic active earth pressures acting on a reinforced wall back and seismic residual deformations of a reinforced wall. Some influence parameters on seismic residual deformations of geogrid reinforced soil retaining walls are investigated in detail, such as the internal friction angles in the backfill sand, friction angles of the wall, horizontal seismic intensities, reinforcement length of the geogrid and soil properties. Finally, the calculated results are compared with test results of a model on large-scale shaking table. The conclusions about the parameters will be helpful for seismic designs of geo-grid reinforced soil retaining walls on liquefied foundations. The proposed pseudo-static calculation method can be used to predict safe seismic deformations of geogrid reinforced soil retaining walls

Pseudo-static calculation method of the seismic residual deformation of a geogrid reinforced soil retaining wall with a liquefied backfill

The geogrid reinforced soil retaining wall is a flexible retaining wall. It will produce large deformations during earthquakes, especially on liquefied backfill soils. An index of liquefaction extent is applied to express the effect of excess pore water pressure in reinforced backfill sand during earthquakes. A geogrid reinforced soil retaining wall is represented by an isotropic vertical elastic beam. The calculation method of the seismic residual deformation of the geogrid reinforced soil retaining wall is based on the Rayleigh-Ritz method and the the Mononobe-Okabe pseudo-static method. The effect of liquefaction extent in the backfill sand is studied for seismic active earth pressures acting on a reinforced wall back and seismic residual deformations of a reinforced wall. Some influence parameters on seismic residual deformations of geogrid reinforced soil retaining walls are investigated in detail, such as the internal friction angles in the backfill sand, friction angles of the wall, horizontal seismic intensities, reinforcement length of the geogrid and soil properties. Finally, the calculated results are compared with test results of a model on large-scale shaking table. The conclusions about the parameters will be helpful for seismic designs of geo-grid reinforced soil retaining walls on liquefied foundations. The proposed pseudo-static calculation method can be used to predict safe seismic deformations of geogrid reinforced soil retaining walls

Pseudo-static calculation method of the seismic residual deformation of a geogrid reinforced soil retaining wall with a liquefied backfill

The geogrid reinforced soil retaining wall is a flexible retaining wall. It will produce large deformations during earthquakes, especially on liquefied backfill soils. An index of liquefaction extent is applied to express the effect of excess pore water pressure in reinforced backfill sand during earthquakes. A geogrid reinforced soil retaining wall is represented by an isotropic vertical elastic beam. The calculation method of the seismic residual deformation of the geogrid reinforced soil retaining wall is based on the Rayleigh-Ritz method and the the Mononobe-Okabe pseudo-static method. The effect of liquefaction extent in the backfill sand is studied for seismic active earth pressures acting on a reinforced wall back and seismic residual deformations of a reinforced wall. Some influence parameters on seismic residual deformations of geogrid reinforced soil retaining walls are investigated in detail, such as the internal friction angles in the backfill sand, friction angles of the wall, horizontal seismic intensities, reinforcement length of the geogrid and soil properties. Finally, the calculated results are compared with test results of a model on large-scale shaking table. The conclusions about the parameters will be helpful for seismic designs of geo-grid reinforced soil retaining walls on liquefied foundations. The proposed pseudo-static calculation method can be used to predict safe seismic deformations of geogrid reinforced soil retaining walls

Novel digital features feature discriminate between drought resistant and drought sensitive rice under controlled and field conditions

Dynamic quantification of drought response is a key issue both for variety selection and for functional genetic study of rice drought resistance. Traditional assessment of drought resistance traits, such as stay-green and leaf-rolling, has utilized manual measurements, that are often subjective, error-prone, poorly quantified and time consuming. To relieve this phenotyping bottleneck, we demonstrate a feasible, robust and non-destructive method that dynamically quantifies response to drought, under both controlled and field conditions. Firstly, RGB images of individual rice plants at different growth points were analyzed to derive 4 features that were influenced by imposition of drought. These include a feature related to the ability to stay green, which we termed greenness plant area ratio (GPAR) and 3 shape descriptors [total plant area/bounding rectangle area ratio (TBR), perimeter area ratio (PAR) and total plant area/convex hull area ratio (TCR)]. Experiments showed that these 4 features were capable of discriminating reliably between drought resistant and drought sensitive accessions, and dynamically quantifying the drought response under controlled conditions across time (at either daily or half hourly time intervals). We compared the 3 shape descriptors and concluded that PAR was more robust and sensitive to leaf-rolling than the other shape descriptors. In addition, PAR and GPAR proved to be effective in quantification of drought response in the field. Moreover, the values obtained in field experiments using the collection of rice varieties were correlated with those derived from pot-based experiments. The general applicability of the algorithms is demonstrated by their ability to probe archival Miscanthus data previously collected on an independent platform. In conclusion, this image-based technology is robust providing a platform-independent tool for quantifying drought response that should be of general utility for breeding and functional genomics in future

Novel digital features feature discriminate between drought resistant and drought sensitive rice under controlled and field conditions

Dynamic quantification of drought response is a key issue both for variety selection and for functional genetic study of rice drought resistance. Traditional assessment of drought resistance traits, such as stay-green and leaf-rolling, has utilized manual measurements, that are often subjective, error-prone, poorly quantified and time consuming. To relieve this phenotyping bottleneck, we demonstrate a feasible, robust and non-destructive method that dynamically quantifies response to drought, under both controlled and field conditions. Firstly, RGB images of individual rice plants at different growth points were analyzed to derive 4 features that were influenced by imposition of drought. These include a feature related to the ability to stay green, which we termed greenness plant area ratio (GPAR) and 3 shape descriptors [total plant area/bounding rectangle area ratio (TBR), perimeter area ratio (PAR) and total plant area/convex hull area ratio (TCR)]. Experiments showed that these 4 features were capable of discriminating reliably between drought resistant and drought sensitive accessions, and dynamically quantifying the drought response under controlled conditions across time (at either daily or half hourly time intervals). We compared the 3 shape descriptors and concluded that PAR was more robust and sensitive to leaf-rolling than the other shape descriptors. In addition, PAR and GPAR proved to be effective in quantification of drought response in the field. Moreover, the values obtained in field experiments using the collection of rice varieties were correlated with those derived from pot-based experiments. The general applicability of the algorithms is demonstrated by their ability to probe archival Miscanthus data previously collected on an independent platform. In conclusion, this image-based technology is robust providing a platform-independent tool for quantifying drought response that should be of general utility for breeding and functional genomics in future

White spot syndrome virus: an overview on an emergent concern

Viruses are ubiquitous and extremely abundant in the marine environment. One of such marine viruses, the white spot syndrome virus (WSSV), has emerged globally as one of the most prevalent, widespread and lethal for shrimp populations. However, at present there is no treatment available to interfere with the unrestrained occurrence and spread of the disease. The recent progress in molecular biology techniques has made it possible to obtain information on the factors, mechanisms and strategies used by this virus to infect and replicate in susceptible host cells. Yet, further research is still required to fully understand the basic nature of WSSV, its exact life cycle and mode of infection. This information will expand our knowledge and may contribute to developing effective prophylactic or therapeutic measures. This review provides a state-of-the-art overview of the topic, and emphasizes the current progress and future direction for the development of WSSV control strategies

Bio-inspired multi-cell tubular structures approaching ideal energy absorption performance

The energy absorption potential of conventional thin-walled tubes is compromised by the long-wavelength folding lobes, which result in a mean crushing force that is much smaller than their yield strength. Here, inspired by the characteristics of the skeletal of the glass sponge, a new thin-walled multi-cell tubular structure with modified face-centered cubic (MFCS) cross section is proposed. The compression behaviors and energy absorbing capacity of the proposed structure were compared with those of the traditional multi-cell tube through finite element simulation and experimental tests. Compared with the traditional multi-cell tubes, the proposed MFCS structure exhibits micro-folding lobes with shorter wavelength, resulting in larger energy absorption, higher energy absorption efficiency and a more stable and controllable deformation mode, with the mean crushing force almost reaching that of an ideal energy absorber. Moreover, the effects of the geometric coefficient of MFCS multi-cell tube on the energy absorption performance and deformation pattern were studied parametrically. Through the bionic design, extraordinary energy absorbing performance is achieved, providing guidance for future design of lightweight structures with unprecedented mechanical properties