Searching for Critical Slip Surface of Slope Based on Flower Pollination Algorithm

In order to determine the critical sliding surface of the slope, the most dangerous sliding surface was searched by flower pollination algorithm. First, the method is applied to the traditional vertical slice method for slope stability analysis. The results are very close to those of the Autobank program, indicating that the method can search the critical sliding surface and find the optimal solution. Then, the method is applied to the new horizontal slice method, and the results of the calculation examples are better than those given in the references, indicating that the application of the flower pollination algorithm to the horizontal slice method is reasonable, reliable and superior. The successful application of this method provides a new method for determining the most dangerous sliding surface of slope

Phytoépuration de boues biologiques provenant de l'industrie agroalimentaire (traitement par un système de marais artificiels à flux vertical en région méditerranéenne française)

Une expérimentation a été menée en mésocosmes pour simuler un marais artificiel à flux vertical pour traiter une boue biologique provenant d une usine agroalimentaire. Un substrat organique (tourbe et écorces de pin) a été utilisé et trois espèces hélophytes (Phragmites australis Cav., Typha latifolia L. et Iris pseudacorus L.) ont été testées. L étude confirme la faisabilité de l utilisation du substrat organique, sans colmatage a déplorer. Mais des matières organiques solubles sont libérées et présentent un risque d enrichissement pour les eaux en sortie. Le système montrent des performances satisfaisantes : réduction hydrique entre 25% et 65%, élimination supérieure à 90% pour MES et DCO, et supérieure à 80% pour NTK. Phragmites est l espèce la plus efficace en termes de traitement, suivie par Typha puis Iris, tous devant le système sol nu. Ceci met en avant le rôle positif du végétal et la variabilité entre les espèces. Le principal processus épuratoire est la filtration. Les plantes ont des effets positifs sur le traitement. De façon indirecte, le système racinaire intensifie la filtration et stimule les activités microbiennes ; les racines exsudent des substances organiques, telles que peroxydases, qui peuvent participer à la dégradation des contaminants. De façon directe, les plantes absorbent des éléments puis les stockent dans la biomasse; ce rôle direct des plantes est mineur mais non négligeable. Phragmites est l espèce la plus efficace en raison de ses caractères les plus appropriés au traitement, comme par exemple une évapotranspiration forte, une forte capacité d absorption, un système racinaire dense, extensif et profond et une forte activité enzymatique.AIX-MARSEILLE1-BU Sci.St Charles (130552104) / SudocSudocFranceF

Influence of plants on microbial activity in a vertical-downflow wetland system treating waste activated sludge with high organic matter concentrations

International audienceThe rhizosphere is a key zone for pollutant removal in treatment wetlands; therefore, studies on microbial activity may provide helpful information for a better understanding of purification processes. We studied microbial activity in a vertical-downflow constructed wetland system treating waste activated sludge with high organic matter concentrations, under Mediterranean climate. The aims of the work were to study the influence of (i) the presence of plants, (ii) the plant species (Phragmites australis Cav., Typha latifolia L., Iris pseudacorus L.), and (iii) the plant growth stage (plant senescence and plant fast growing stage) on total respiration rate and phosphatase activity in the substrate (intented here as the solid support on which the plants grow). The presence of plants had a positive influence on microbial activity, since substrate respiration and both acid and alkaline phosphatase activity were always higher in planted than in unplanted mesocosms. Among the three tested species, Phragmites was the one that most stimulated both substrate respiration rate and phosphatase activity, followed by Typha and Iris. These differences of microbial activity between mesocosms were corresponding to differences of removal efficiency. Substrate respiration and phosphatase activity were of similar magnitude at the two growth stages, while the stimulating effect of plants seemed to have been delayed and microbial activity showed higher fluctuations at plant fast growing stage than at plant senescence

Purification processes involved in sludge treatment by a vertical flow wetland system: Focus on the role of the substrate and plants on N and P removal

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A Fast and Accurate Spatial Target Snapping Method for 3D Scene Modeling and Mapping in Mobile Augmented Reality

High-performance spatial target snapping is an essential function in 3D scene modeling and mapping that is widely used in mobile augmented reality (MAR). Spatial data snapping in a MAR system must be quick and accurate, while real-time human–computer interaction and drawing smoothness must also be ensured. In this paper, we analyze the advantages and disadvantages of several spatial data snapping algorithms, such as the 2D computational geometry method and the absolute distance calculation method. To address the issues that existing algorithms do not adequately support 3D data snapping and real-time snapping of high data volumes, we present a new adaptive dynamic snapping algorithm based on the spatial and graphical characteristics of augmented reality (AR) data snapping. Finally, the algorithm is experimented with by an AR modeling system, including the evaluation of snapping efficiency and snapping accuracy. Through the experimental comparison, we found that the algorithm proposed in this paper is substantially improved in terms of shortening the snapping time, enhancing the snapping stability, and improving the snapping accuracy of vector points, lines, faces, bodies, etc. The snapping efficiency of the algorithm proposed in this paper is 1.6 times higher than that of the traditional algorithm on average, while the data acquisition accuracy based on the algorithm in this paper is more than 6 times higher than that of the traditional algorithm on average under the same conditions, and its data accuracy is improved from the decimeter level to the centimeter level

Depollution potential of three macrophytes: Exudated, wall-bound and intracellular peroxidase activities plus intracellular phenol concentrations

International audienceThe aim of this study was to investigate the potential role of three macrophyte species (Iris pseudacorus, Typha latifolia and Phragmites australis) for detoxication of xenobiotics, and to study their variations with seasons or concentrations of sewage sludge from the food industry. For this purpose, some aspects of the green liver concept were explored through peroxidase measurements in three compartments in roots: intracellular, cell wall and extracellular. In addition, phenol concentrations were also measured in order to assess heavy metal detoxication potential. Enzyme activities and phenol concentrations were overall lower in winter according to the phenological stages and some sludge effects occurred. Results show that P. australis roots exuded and contained more peroxidase in all seasons: 17 U/g (1373 U/g protein), 0.8 U/g (613 U/g protein) and 4.8 U/g (1329 U/g protein) in intracellular compartments, cell wall and exudates, respectively. In contrast, the highest phenol concentration was found in I. pseudacorus roots: 143.3 mg eq. gallic acid/g. Hence, in constructed wetlands, P. australis is suitable for organic waste water treatment, while I. pseudacorus should be used in the case of waters highly charged with heavy metals

Influencing Factors on Forest Biomass Carbon Storage in Eastern China – A Case Study of Jiangsu Province

Forest vegetation plays a crucial role in improving the ecological environment and maintaining the regional ecological balance. However, most studies pay little attention to the factors that can impact forest biomass carbon storage (FBCS). This research estimated the FBCS by combining relevant forest inventory data and models of continuous functions for biomass expansion factor. A modeling equation was then established and applied to examine the impact of socioeconomic factors on FBCS in Jiangsu, a coastal province in Eastern China, as a case study. The results showed that Jiangsu’s FBCS increased by 20.28 Tg from 2005 to 2010, showing a prominent carbon sink effect but with spatial imbalance among the changes in carbon storage. Jiangsu’s FBCS is significantly affected by land use factors (e.g., forest area and cultivated area), population factors (e.g., population density and urbanization), and economic development factors (e.g., GDP). Relatively speaking, the forest area and GDP had positive effects on FBCS, while cultivated area, population density, and urbanization had significant negative effects

Agarose-Degrading Characteristics of a Deep-Sea Bacterium Vibrio Natriegens WPAGA4 and Its Cold-Adapted GH50 Agarase Aga3420

Up until now, the characterizations of GH50 agarases from Vibrio species have rarely been reported compared to GH16 agarases. In this study, a deep-sea strain, WPAGA4, was isolated and identified as Vibrio natriegens due to the maximum similarity of its 16S rRNA gene sequence, the values of its average nucleotide identity, and through digital DNA–DNA hybridization. Two circular chromosomes in V. natriegens WPAGA4 were assembled. A total of 4561 coding genes, 37 rRNA, 131 tRNA, and 59 other non-coding RNA genes were predicted in the genome of V. natriegens WPAGA4. An agarase gene belonging to the GH50 family was annotated in the genome sequence and expressed in E. coli cells. The optimum temperature and pH of the recombinant Aga3420 (rAga3420) were 40 °C and 7.0, respectively. Neoagarobiose (NA2) was the only product during the degradation process of agarose by rAga3420. rAga3420 had a favorable stability following incubation at 10–30 °C for 50 min. The Km, Vmax, and kcat values of rAga3420 were 2.8 mg/mL, 78.1 U/mg, and 376.9 s−1, respectively. rAga3420 displayed cold-adapted properties as 59.7% and 41.2% of the relative activity remained at 10 3 °C and 0 °C, respectively. This property ensured V. natriegens WPAGA4 could degrade and metabolize the agarose in cold deep-sea environments and enables rAga3420 to be an appropriate industrial enzyme for NA2 production, with industrial potential in medical and cosmetic fields