Prediction of debris flow occurrence in jiuzhui gully based on field investigation

Jiuzhui gully is located in the Jiexu hydropower station project area, where the debris flow in Jiuzhui gully poses a great threat not only to the construction process, but also to the future operation. With the aim of reducing the risk of disaster caused by debris flow in Jiuzhui gully watershed, we conducted a systematic field investigation to obtain the basic data of this basin. In addition, remote sensing interpretation was employed to identify the area and location of source materials. By means of field investigation, the fundamental data of the whole basin can be acquired, including the topography, angles of the slopes, rainfall conditions, vegetation coverage condition and seismic activity. Combining the field investigation with remote sensing interpretation, the amount of the loose deposits can be calculated, and debris flow initiation can be preliminarily analysed. Subsequently, the debris flow development trend in Jiuzhui gully watershed can be determined from different perspectives. Finally, on the basis of the obtained data, a comprehensive analysis can be conducted, and the conclusion can be drawn that the source materials, rainfall conditions and energy conditions can easily initiate debris flow. So, without engineering countermeasures or an early warning system, the debris flow in Jiuzhui gully may pose a great risk to the construction process and future operation of the hydropower station. In addition, the frequency and scale of the debris flow will be greatly magnified under the coupled effect of a strong earthquake and heavy rainfall

Debris flow forecast based on soil-water coupling mechanism: a case study in Aizi gully watershed

On 28 June 2012, a huge disastrous debris flow occurred in Aizi gully watershed which is situated in Ningnan County, Sichuan Province, China. This debris flow event not only resulted in 40 people being dead or missing, but also seriously affected the construction process of Baihetan Hydropower station. With the aim of reducing the influence of the debris flow on local economy development and people’s life, a field investigation and remote sensing interpretation were carried out to explore the whole condition of this area, including the amount of loose deposits, topography conditions and rainfall amount, etc. We concluded that the loose materials, rainfall conditions and topography still satisfied the conditions for debris flow initiation. In the future, under intensive rainfall a large scale debris flow could probably occur in this area, which would pose a grave threat to the safety of the residents. To reduce the risk posed by future debris flows in Aizi gully watershed, a soil-water coupling model was employed to calculate the mixture density, and evaluate the occurrence probability of the debris flow, and assess the corresponding warning grade. On the basis of the results of model calculation, combined with the real-time rainfall condition, timely forecast information can be issued. This in turn can significantly facilitate disaster mitigation and prevention, and the potential disaster of debris flow in Aizi gully can be minimized

Analysis of the correlation between strength and fractal dimension of gravelly soil in debris-flow source areas

Particle size distribution of gravelly soil plays a crucial role in debris flow initiation. For better understanding the mechanism of debris flow formation, two crucial mechanical property parameters of the gravelly soil are required to be studied meticulously: hydraulic conductivity and strength. With the aim of measuring the composition of the gravelly soil, 182 soil samples were taken from debris flow prone areas. With the aid of a sieve test, the particle size distribution of the samples can be obtained and analyzed. Then fractal theory was employed to compute the fractal dimension of the soil samples. By analyzing the results of sieve test (particle size distribution curves) and the results of the fractal theory calculations, the relationship between fractal dimension and particle size distribution can be explored. The results illustrate that the particle compositions of the gravelly soil tends to remain uniform as the fractal dimension increases. Moreover, as the coarse particle content increases, the fractal dimension decreases. To better understand the formation mechanism of debris flows, direct shear tests were conducted. Subsequently the experimental results were analyzed. By analysis, the following conclusions can be drawn: the soil strength decreases as the fractal dimension increases, and for soils with lower moisture content and identical dry density, a linear relationship between fractal dimension and cohesion force was identified. Moreover, cohesion force and internal friction force both decrease as the fractal dimension increases, but the internal friction angle decreases slightly while the cohesion force decreases greatly. Therefore we concluded that soil strength decreased mainly due to the reduction in cohesion force

Mixed-Matrix Membranes Containing Carbon Nanotubes Composite with Hydrogel for Efficient CO₂ Separation

In this study, a carbon nanotubes composite coated with <i>N</i>-isopropylacrylamide hydrogel (NIPAM-CNTs) was synthesized. Mixed-matrix membranes (MMMs) were fabricated by incorporating NIPAM-CNTs composite filler into poly­(ether-<i>block</i>-amide) (Pebax MH 1657) matrix for efficient CO₂ separation. The as-prepared NIPAM-CNTs composite filler mainly plays two roles: (i) The extraordinary smooth one-dimensional nanochannels of CNTs act as the highways to accelerate CO₂ transport through membranes, increasing CO₂ permeability; (ii) The NIPAM hydrogel layer coated on the outer walls of CNTs acts as the super water absorbent to increase water content of membranes, appealing both CO₂ permeability and CO₂/gas selectivity. MMM containing 5 wt % NIPAM-CNTs exhibited the highest CO₂ permeability of 567 barrer, CO₂/CH₄ selectivity of 35, and CO₂/N₂ selectivity of 70, transcending 2008 Robeson upper bound line. The improved CO₂ separation performance of MMMs is mainly attributed to the construction of the efficient CO₂ transport pathways by NIPAM-CNTs. Thus, MMMs incorporated with NIPAM-CNTs composite filler can be used as an excellent membrane material for efficient CO₂ separation

Sulfolane Crystal Templating: A One-Step and Tunable Polarity Approach for Self-Assembled Super-Macroporous Hydrophobic Monoliths

Freeze-casting (ice templating) is generally used to prepare super-macroporous materials. However, water solubility limits the application of freeze-casting in hydrophobic material fabrication. In the present work, inexpensive and low-toxic sulfolane was used as a novel crystallization-induced porogen (sulfolane crystal templating) to prepare super-macroporous hydrophobic monoliths (cryogels) with tunable polarity. The phase transition of sulfolane consisted of reversible processes in the liquid, semi-crystalline, and crystalline states. Because of the density change during phase transition, liquid sulfolane experienced a 16.4% volume shrinkage per unit mass. Thus, the cryogels obtained using the conventional freezing method contained obvious hollow-shaped defects. Furthermore, a novel route of pre-cooling, pre-crystallization, crystal growth, freezing, and thawing (PPCFT) was employed to prepare cryogels with defect-free macroscopic morphology and uniform pore structure. The as-obtained cryogels were composed of a super-macroporous structures and interconnected channels, and their porosity ranged between 85 and 97%. Moreover, the cryogels manifested good hydrophobicity (contact angle = 120–130°) and had absorption capacities greater than 10 g g–1 for oils and organic liquids. The maximum absorption capacities of the resultant cryogels in dichloromethane, ethyl acetate, and liquid paraffin were 60.3, 35.8, and 15.2 g g–1, respectively. Moreover, sulfolane could conveniently dissolve hydrophobic and hydrophilic monomers to generate amphiphilic cryogels (contact angle = 130–0°). Therefore, sulfolane crystal templating is a potential fabrication method for super-macroporous hydrophobic materials with tunable polarity

Suppression of Bacterial Wilt of Tomato by Bioorganic Fertilizer Made from the Antibacterial Compound Producing Strain Bacillus amyloliquefaciens HR62

Ralstonia solanacearum (Smith) is an important soil-borne pathogen worldwide. We investigated the effects of a new bioorganic fertilizer, BIO62, which was made from organic fertilizer and antagonist Bacillus amyloliquefaciens HR62, on the control of bacterial wilt of tomato in greenhouse condition. The results showed that the application of BIO62 significantly decreased disease incidence by 65% and strongly reduced R. solanacearum populations both in the rhizosphere soil (8.04 log cfu g^–1 dry soil) and crown sections (5.63 log cfu g^–1 fresh plant section) at 28 days after pathogen challenge. Antibacterial compounds produced by HR62 were purified by silica gel, Sephadex LH-20, and HPLC and then identified using HPLC/electrospray ionization mass spectrometry analysis. Macrolactin A and 7-<i>O</i>-malonyl macrolactin A (molecular weights of 402 and 488 Da, respectively), along with surfactin B (molecular weights of 994, 1008, 1022, and 1036 Da), were observed to inhibit the growth of R. solanacearum

All data

All the data are put in this fil

All data for the manuscript

The attached file is all the raw data for the manuscript which also including the arcsine-transformed proportional data and the average value for each treatment at the replicated population level

Nonlinear regression analyses (Equation: Sigmoidal, Sigmoid, 3-Parameter) between mean maximum temperature averaged over crop season (<i>T</i>_<i>cs</i>) and both biocontrol efficacy of BOF (black line) and disease incidence in control treatment (grey line).

<p>Nonlinear regression analyses (Equation: Sigmoidal, Sigmoid, 3-Parameter) between mean maximum temperature averaged over crop season (<i>T</i>_<i>cs</i>) and both biocontrol efficacy of BOF (black line) and disease incidence in control treatment (grey line).</p

Changes in the mean maximum temperature (panel A) for every 10-day time period after transplantation (<i>T</i>_<i>10</i>) and in the mean maximum temperature (panel B) during the entire crop season (<i>T</i>_<i>cs</i>) for the early-spring (ES, black circle), late-spring (LS, white circle), early-autumn (EA, white triangle) and late-autumn (LA, black triangle) crop seasons transplantation treatments in 2011 and 2012.

<p>Bars show standard error of mean (SEM) in all panels. Dashed lines in all panels indicate T_<i>10</i> or T_<i>cs</i> equal to 25°C Different letters in lowercase on the top of the bar represent significance (Duncan’s multiple range test, <i>P</i> < 0.05).</p