Numerical investigation of bed-load changes on sediment flushing cavity

The tanks' useful life will be reduced if their sediments are not discharged with a suitable method. Various hydraulic and mechanical methods can be used in many countries to discharge sediments from reservoirs. Pressure hydraulic sediment flushing is a method of sediment flushing without lowering the water level. In the present study, using the CFD based Flow-3D software, a model has been applied to investigate the pressure hydraulic sediment flushing, and evaluate the effect of blockage phenomenon on sediment flushing efficiency. Results were compared with the available laboratory model. The dimensions of the simulated tank were 2.5 x 1.3 x 1.5 m in length, width and height, respectively, the height of the bed load was 0.4 m, and the diameter of the sediment particles was 0.3 mm according to the laboratory conditions. The average relative error for the sediment flushing cone depth was about 3%. In addition, to investigate the blocking phenomenon, the height of the bed load was considered to be 0.41, 0.45 and 0.5 meters for each simulation. The simulation results showed that when the height of the bed load increases, there is the highest sediment flushing efficiency and more sediment can be removed from the bottom outlet

A comparative study of mechanical properties and life cycle assessment of high-strength concrete containing silica fume and nanosilica as a partial cement replacement

peer reviewe

Dissecting molecular mechanisms underlying salt tolerance in rice: a comparative transcriptional profiling of the contrasting genotypes

Abstract Background Salinity expansion in arable land is a threat to crop plants. Rice is the staple food crop across several countries worldwide; however, its salt sensitive nature severely affects its growth under excessive salinity. FL478 is a salt tolerant indica recombinant inbred line, which can be a good source of salt tolerance at the seedling stage in rice. To learn about the genetic basis of its tolerance to salinity, we compared transcriptome profiles of FL478 and its sensitive parent (IR29) using RNA-seq technique. Results A total of 1714 and 2670 genes were found differentially expressed (DEGs) under salt stress compared to normal conditions in FL478 and IR29, respectively. Gene ontology analysis revealed the enrichment of transcripts involved in salinity response, regulation of gene expression, and transport in both genotypes. Comparative transcriptome analysis revealed that 1063 DEGs were co-expressed, while 338/252 and 572/908 DEGs were exclusively up/down-regulated in FL478 and IR29, respectively. Further, some biological processes (e.g. iron ion transport, response to abiotic stimulus, and oxidative stress) and molecular function terms (e.g. zinc ion binding and cation transmembrane transporter activity) were specifically enriched in FL478 up-regulated transcripts. Based on the metabolic pathways analysis, genes encoding transport and major intrinsic proteins transporter superfamily comprising aquaporin subfamilies and genes involved in MAPK signaling and signaling receptor kinases were specifically enriched in FL478. A total of 1135 and 1894 alternative splicing events were identified in transcripts of FL478 and IR29, respectively. Transcripts encoding two potassium transporters and two major facilitator family transporters were specifically up-regulated in FL478 under salt stress but not in the salt sensitive genotype. Remarkably, 11 DEGs were conversely regulated in the studied genotypes; for example, OsZIFL, OsNAAT, OsGDSL, and OsELIP genes were up-regulated in FL478, while they were down-regulated in IR29. Conclusions The achieved results suggest that FL478 employs more efficient mechanisms (especially in signal transduction of salt stress, influx and transport of k+, ionic and osmotic homeostasis, as well as ROS inhibition) to respond to the salt stress compared to its susceptible parent