An efficient nd-point data structure for querying flood risk

Governments use flood maps for city planning and disaster management to protect people and assets. Flood risk mapping projects carried out for these purposes generate a huge amount of modelling results. Previously, data submitted are highly condensed products such as typical flood inundation maps and tables for loss analysis. Original modelling results recording critical flood evolution processes are overlooked due to cumbersome management and analysis. This certainly has drawbacks: the ĝ€ static' maps impart few details about the flood; also, the data fails to address new requirements. This significantly confines the use of flood maps. Recent development of point cloud databases provides an opportunity to manage the whole set of modelling results. The databases can efficiently support all kinds of flood risk queries at finer scales. Using a case study from China, this paper demonstrates how a novel nD-PointCloud structure, HistSFC, improves flood risk querying. The result indicates that compared with conventional database solutions, HistSFC holds superior performance and better scalability. Besides, the specific optimizations made on HistSFC can facilitate the process further. All these indicate a promising solution for the next generation of flood maps.GIS Technologi

Process-time Optimization of Vacuum Degassing Using a Genetic Alloy Design Approach

This paper demonstrates the use of a new model consisting of a genetic algorithm in combination with thermodynamic calculations and analytical process models to minimize the processing time during a vacuum degassing treatment of liquid steel. The model sets multiple simultaneous targets for final S, N, O, Si and Al levels and uses the total slag mass, the slag composition, the steel composition and the start temperature as optimization variables. The predicted optimal conditions agree well with industrial practice. For those conditions leading to the shortest process time the target compositions for S, N and O are reached almost simultaneously.Aerospace Structures & MaterialsAerospace Engineerin

Long-term nitrogen addition decreases carbon leaching in a nitrogen-rich forest ecosystem

Dissolved organic carbon (DOC) plays a critical role in the carbon (C) cycle of forest soils, and has been recently connected with global increases in nitrogen (N) deposition. Most studies on effects of elevated N deposition on DOC have been carried out in N-limited temperate regions, with far fewer data available from N-rich ecosystems, especially in the context of chronically elevated N deposition. Furthermore, mechanisms for excess N-induced changes of DOC dynamics have been suggested to be different between the two kinds of ecosystems, because of the different ecosystem N status. The purpose of this study was to experimentally examine how long-term N addition affects DOC dynamics below the primary rooting zones (the upper 20 cm soils) in typically N-rich lowland tropical forests. We have a primary assumption that long-term continuous N addition minimally affects DOC concentrations and effluxes in N-rich tropical forests. Experimental N addition was administered at the following levels: 0, 50, 100 and 150 kg N ha⁻¹ yr⁻¹, respectively. Results showed that seven years of N addition significantly decreased DOC concentrations in soil solution, and chemo-physical controls (solution acidity change and soil sorption) rather than biological controls may mainly account for the decreases, in contrast to other forests. We further found that N addition greatly decreased annual DOC effluxes from the primary rooting zone and increased water-extractable DOC in soils. Our results suggest that long-term N deposition could increase soil C sequestration in the upper soils by decreasing DOC efflux from that layer in N-rich ecosystems, a novel mechanism for continued accumulation of soil C in old-growth forests.Journal ArticleFinal article publishe

Directional attraction of fluid surface wave caused by vertically oscillating prisms

Experiments show that the surface wave, which is caused by a triangular prism performing simple harmonic vibration with low frequency and small amplitude on fluid surface, has directional force on float. A series of experiments and an in-depth study about this phenomenon were carried out, and the characteristics of fluid surface wave from different structures oscillation were analyzed. Experiments were launched with different vertical oscillating structures, such as triangular prism, quadrangular prism, hexagonal prism and the cylinder. The results show that the surface wave, on the direction directly opposite to the prism edge, can attract the floats, while the wave on the direction directly opposite to the prism facet has repelling interection. The relationship between the strength of attraction and sharpness of the angle is non-linear. The sharper the angle, the stronger the attraction force. When the prism becomes a cylinder which means without angle, the attraction will disappear. The experiment found and verified the fluid surface wave caused by specific structure oscillating prisms has directional attraction interection. The results are helpful for cleaning up pollutants and collecting spill oil on the water.</p

Seasonal Variations of C: N: P Stoichiometry and Their Trade-Offs in Different Organs of Suaeda salsa in Coastal Wetland of Yellow River Delta, China

Variations of plant C: N: P stoichiometry could be affected by both some environmental fluctuations and plant physiological processes. However, the trade-off mechanism between them and their influencial factors were not understood completely. In this study, C, N, P contents and their stoichiometry of S. salsa's plant organs (leaves, stems, and roots), together with their environmental factors including salinity, pH, soil N and soil P, were examined in the intertidal and supratidal habitats of coastal wetlands during the different sampling times (May, July, September, November). The results showed that both plant organ and sampling times affected C, N, and P and stoichiometry of S. salsa in the intertidal and supratidal habitats, however, their influencial conditions and mechanisms were different. In the intertidal habitat, the different slopes of C-P and N-P within interspecific organs suggested that plant P, C: P and N: P of S. salsa were modulated by P concentrations that allocated in the specific organs. However, the slopes of C-N were found to be not significant within interspecific organs, but during the sampling times. These differences of plant N and C: N were related with the physiological demand for N in the specific life history stage. In the supratidal habitat, no significant differences were found in the slopes of C-N, C-P, and N-P within interspecific organs. However, different slopes of C-N among the sampling times also indicated a self-regulation strategy for plant N and C: N of S. salsa in different ontogenetic stages. In contrast to the intertidal habitat, seasonal variations of P, C: P and N: P ratios within interspecific organs reflected the soil P characteristics in the supratidal habitat. Our results showed that the stoichiometric constraint strategy of plant S. salsa in this region was strongly correlated with the local soil nutrient conditions

De novo assembly and characterization of the root transcriptome of Aegilops variabilis during an interaction with the cereal cyst nematode

Background: Aegilops variabilis No. 1 is highly resistant to cereal cyst nematode (CCN). However, a lack of genomic information has restricted studies on CCN resistance genes in Ae. variabilis and has limited genetic applications in wheat breeding. Results: Using RNA-Seq technology, we generated a root transcriptome at a sequencing depth of 4.69 gigabases of Ae. variabilis No. 1 from a pooled RNA sample. The sample contained equal amounts of RNA extracted from CCN-infected and untreated control plants at three time-points. Using the Trinity method, nearly 52,081,238 high-quality trimmed reads were assembled into a non-redundant set of 118,064 unigenes with an average length of 500 bp and an N50 of 599 bp. The total assembly was 59.09 Mb of unique transcriptome sequences with average read-depth coverage of 33.25x. In BLAST searches of our database against public databases, 66.46% (78,467) of the unigenes were annotated with gene descriptions, conserved protein domains, or gene ontology terms. Functional categorization further revealed 7,408 individual unigenes and three pathways related to plant stress resistance. Conclusions: We conducted high-resolution transcriptome profiling related to root development and the response to CCN infection in Ae. variabilis No.1. This research facilitates further studies on gene discovery and on the molecular mechanisms related to CCN resistance

The ecological adaptability of four typical plants during the early successional stage of a tropical rainforest

The ecological adaptability of four typical plants (two grasses: Thysanolaena maxima and Miscanthus floridulus; two shrubs: Melastoma candidum and Melastoma sanguineum) in the early successional stage of a tropical rainforest in Hainan Island of China was studied. Our purpose was to test the difference of the adaptive modes and ecological functions for four different functional groups. We measured the physiological parameters and morphological indexes to define the adaptability of the plants at this stage. Results showed that T. maxima possessed stronger water use ability, whose adaptation was mainly by the morphological architecture regulation strategy (by higher leaf self-shading). M. floridulus had greater water regulation ability and its adaptation was mainly through the physiological regulation strategy (by higher net photosynthetic rate (A) and water use efficiency). However, M. candidum and M. sanguineum integrated the morphological architecture and physiological strategies (by high A and leaf self-shading). According to the ecophysiological characteristics and adaptation modes, the plants in the early successional stage of the tropical rainforest in Hainan Island can be categorized into three functional groups: (1) physiological adaptation group, (2) morphological adaptation group, and (3) physiological and morphological integrated adaptation group.The ecological adaptability of four typical plants (two grasses: Thysanolaena maxima and Miscanthus floridulus; two shrubs: Melastoma candidum and Melastoma sanguineum) in the early successional stage of a tropical rainforest in Hainan Island of China was studied. Our purpose was to test the difference of the adaptive modes and ecological functions for four different functional groups. We measured the physiological parameters and morphological indexes to define the adaptability of the plants at this stage. Results showed that T. maxima possessed stronger water use ability, whose adaptation was mainly by the morphological architecture regulation strategy (by higher leaf self-shading). M. floridulus had greater water regulation ability and its adaptation was mainly through the physiological regulation strategy (by higher net photosynthetic rate (A) and water use efficiency). However, M. candidum and M. sanguineum integrated the morphological architecture and physiological strategies (by high A and leaf self-shading). According to the ecophysiological characteristics and adaptation modes, the plants in the early successional stage of the tropical rainforest in Hainan Island can be categorized into three functional groups: (1) physiological adaptation group, (2) morphological adaptation group, and (3) physiological and morphological integrated adaptation group